import

2024-12-02 20:45:02 +01:00 · 2023-06-15 16:26:11 +02:00 · 2023-06-15 16:26:11 +02:00 · 003841d66c
commit 003841d66c
50 changed files with 2355 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,12 @@
+/.idea/
+__pycache__/
+
+# pip build
+/src/de.p1st.monitor.egg-info/
+/dist/
+/build/
+/venv/
+
+# makepkg
+/packaging/python-de-p1st-monitor-git-*-any.pkg.tar.zst
+/packaging/de-p1st-monitor/
--- a/(export).run.xml
+++ b/(export).run.xml
@ -0,0 +1,24 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="main (export)" type="PythonConfigurationType" factoryName="Python">
+    <module name="de-p1st-monitor" />
+    <option name="INTERPRETER_OPTIONS" value="" />
+    <option name="PARENT_ENVS" value="true" />
+    <envs>
+      <env name="PYTHONUNBUFFERED" value="1" />
+    </envs>
+    <option name="SDK_HOME" value="" />
+    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/src/de/p1st/monitor" />
+    <option name="IS_MODULE_SDK" value="true" />
+    <option name="ADD_CONTENT_ROOTS" value="true" />
+    <option name="ADD_SOURCE_ROOTS" value="true" />
+    <EXTENSION ID="PythonCoverageRunConfigurationExtension" runner="coverage.py" />
+    <option name="SCRIPT_NAME" value="$PROJECT_DIR$/src/de/p1st/monitor/main.py" />
+    <option name="PARAMETERS" value="-c $PROJECT_DIR$/cfg/yodaTux.ini --export" />
+    <option name="SHOW_COMMAND_LINE" value="false" />
+    <option name="EMULATE_TERMINAL" value="false" />
+    <option name="MODULE_MODE" value="false" />
+    <option name="REDIRECT_INPUT" value="false" />
+    <option name="INPUT_FILE" value="" />
+    <method v="2" />
+  </configuration>
+</component>
--- a/(help).run.xml
+++ b/(help).run.xml
@ -0,0 +1,24 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="main (help)" type="PythonConfigurationType" factoryName="Python">
+    <module name="de-p1st-monitor" />
+    <option name="INTERPRETER_OPTIONS" value="" />
+    <option name="PARENT_ENVS" value="true" />
+    <envs>
+      <env name="PYTHONUNBUFFERED" value="1" />
+    </envs>
+    <option name="SDK_HOME" value="" />
+    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/src/de/p1st/monitor" />
+    <option name="IS_MODULE_SDK" value="true" />
+    <option name="ADD_CONTENT_ROOTS" value="true" />
+    <option name="ADD_SOURCE_ROOTS" value="true" />
+    <EXTENSION ID="PythonCoverageRunConfigurationExtension" runner="coverage.py" />
+    <option name="SCRIPT_NAME" value="$PROJECT_DIR$/src/de/p1st/monitor/main.py" />
+    <option name="PARAMETERS" value="--help" />
+    <option name="SHOW_COMMAND_LINE" value="false" />
+    <option name="EMULATE_TERMINAL" value="false" />
+    <option name="MODULE_MODE" value="false" />
+    <option name="REDIRECT_INPUT" value="false" />
+    <option name="INPUT_FILE" value="" />
+    <method v="2" />
+  </configuration>
+</component>
--- a/(log).run.xml
+++ b/(log).run.xml
@ -0,0 +1,24 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="main (log)" type="PythonConfigurationType" factoryName="Python">
+    <module name="de-p1st-monitor" />
+    <option name="INTERPRETER_OPTIONS" value="" />
+    <option name="PARENT_ENVS" value="true" />
+    <envs>
+      <env name="PYTHONUNBUFFERED" value="1" />
+    </envs>
+    <option name="SDK_HOME" value="" />
+    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/src/de/p1st/monitor" />
+    <option name="IS_MODULE_SDK" value="true" />
+    <option name="ADD_CONTENT_ROOTS" value="true" />
+    <option name="ADD_SOURCE_ROOTS" value="true" />
+    <EXTENSION ID="PythonCoverageRunConfigurationExtension" runner="coverage.py" />
+    <option name="SCRIPT_NAME" value="$PROJECT_DIR$/src/de/p1st/monitor/main.py" />
+    <option name="PARAMETERS" value="-c $PROJECT_DIR$/cfg/yodaTux.ini" />
+    <option name="SHOW_COMMAND_LINE" value="false" />
+    <option name="EMULATE_TERMINAL" value="false" />
+    <option name="MODULE_MODE" value="false" />
+    <option name="REDIRECT_INPUT" value="false" />
+    <option name="INPUT_FILE" value="" />
+    <method v="2" />
+  </configuration>
+</component>
--- a/32
+++ b/32
@ -0,0 +1,32 @@
+The Clear BSD License
+
+Copyright (c) 2023 Daniel Langbein
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted (subject to the limitations in the disclaimer
+below) provided that the following conditions are met:
+
+     * Redistributions of source code must retain the above copyright notice,
+     this list of conditions and the following disclaimer.
+
+     * Redistributions in binary form must reproduce the above copyright
+     notice, this list of conditions and the following disclaimer in the
+     documentation and/or other materials provided with the distribution.
+
+     * Neither the name of the copyright holder nor the names of its
+     contributors may be used to endorse or promote products derived from this
+     software without specific prior written permission.
+
+NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY
+THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
--- a/47
+++ b/47
@ -0,0 +1,47 @@
+PKGNAME := de-p1st-monitor
+
+.PHONY: all
+all: install-pkgbuild
+
+.PHONY: install-pkgbuild
+install-pkgbuild: cron  ## Install with pacman (on Arch Linux)
+	sudo pacman -S --needed base-devel
+	cd packaging && makepkg -fCcsri && rm -rf $(PKGNAME)
+	${MAKE} install-files
+
+.PHONY: install-pip
+install-pip: notify cron  ## Install with pip
+	sudo python3 -m pip install --upgrade --force-reinstall .
+	${MAKE} install-files
+
+.PHONY: install-files
+install-files:
+	sudo install -m0644 cron.d/$(PKGNAME) /etc/cron.d/$(PKGNAME)
+
+	sudo install --directory -m755 /etc/$(PKGNAME)/
+	sudo install -m0644 cfg/* /etc/$(PKGNAME)/
+
+.PHONY: notify  ## Check if exec-notify is installed.
+notify:
+	# `type` does not work e.g. on Ubuntu 18.04
+	which exec-notify
+
+.PHONY: cron  ## Check if cron (e.g. cronie) is running.
+cron:
+	# Check if cron.d exists
+	stat /etc/cron.d/
+	# Check if cron is running
+	pgrep cron
+
+
+.PHONY: clean-pkgbuild
+clean-pkgbuild: clean-files
+	sudo pacman -Rns python-$(PKGNAME)-git
+
+.PHONY: clean-pip
+clean-pip: clean-files
+	sudo python3 -m pip uninstall -y $(PKGNAME)
+
+.PHONY: clean-files
+clean-files:
+	sudo rm -rf /etc/cron.d/$(PKGNAME) /etc/$(PKGNAME) /var/log/$(PKGNAME).cron
--- a/README.md
+++ b/README.md
@ -0,0 +1,248 @@
+# de-p1st-monitor
+
+## Research
+
+See [./research](./research).
+
+- HDD temp:
+  - Modern hard drives will throttle their read and write speeds
+    when the drive reaches a critical pre-set temperature
+    (usually around 60°C)
+  - 20-50°C (short-term)
+  - 20-40°C (long-term usage)
+- SSD temp:
+  - Most SSDs implement thermal throttling as a safety feature
+    if a drive gets too hot. As the driver approaches the 70ºC limit
+    that most manufacturers set, the more likely it is that the
+    drive will start to slow itself down to prevent failure.
+  - 30-50°C
+
+## Keep it simple!
+
+Lines of code including docstrings and comments:
+
+```shell
+find ./src -name '*.py' | xargs wc -l
+#=> 1394 total
+```
+
+## Configuration
+
+See [cfg/yodaTux.ini](cfg/yodaTux.ini) for a configuration file covering all config options.
+
+## Installation
+
+Install dependencies:
+
+- on Arch Linux
+
+```shell
+# TODO
+# Optional: 1-wire temperature sensor.
+sudo pacman -S digitemp  # TODO: configure your sensor
+```
+
+- on Ubuntu
+
+```shell
+sudo apt-get install python3-pip
+
+# Ubuntu 18.04 and below
+sudo apt-get install python3-setuptools
+sudo apt-get install python3-wheel
+
+sudo apt-get install python3-psutil
+
+# Ubuntu 18.04 and below: psutil < 5.6.2
+sudo apt-get install python3-dev
+sudo apt-get install build-essential
+# Ubuntu 20.04 and below: psutil < 5.6.2
+sudo python3 -m pip install psutil --upgrade
+```
+
+Install:
+
+- on Arch Linux
+
+```shell
+make
+```
+
+- on Ubuntu
+
+```shell
+make install-pip
+```
+
+## Usage
+
+### Command line interface
+
+```
+usage: de-p1st-monitor [-h] [--config CONFIG] [--export]
+
+Iterates over all config sections. For each section the current sensor data is
+read and logged to a .csv file.
+
+options:
+  -h, --help            show this help message and exit
+  --config CONFIG, -c CONFIG
+                        Path to .ini configuration file.
+  --export, -e          If `True`, export .csv files and print their paths to
+                        stdout. No sensor data is logged during this.
+```
+
+### Periodic logging
+
+Add a cron entry executing this e.g. every 3 Minutes:
+
+```shell
+de-p1st-monitor
+```
+
+## Example log files
+
+```shell
+ssh nas 'tail -n 1 /var/log/de-p1st-monitor/*'
+```
+```
+==> /var/log/de-p1st-monitor/cpu_15min.csv <==
+20230315T103001,0.10400390625
+
+==> /var/log/de-p1st-monitor/cpu_1min.csv <==
+20230315T103001,0.03076171875
+
+==> /var/log/de-p1st-monitor/cpu_5min.csv <==
+20230315T103001,0.0301513671875
+
+==> /var/log/de-p1st-monitor/drive_20d86155-30d4-404c-95e8-c701cfb16ca5.csv <==
+20230315T103001,24
+
+==> /var/log/de-p1st-monitor/drive_4651c3f1-e4b8-45aa-a823-df762530a307.csv <==
+20230315T103001,21
+
+==> /var/log/de-p1st-monitor/drive_68c349e8-5118-4773-9fd5-5dbad9acee4e.csv <==
+20230315T103001,29
+
+==> /var/log/de-p1st-monitor/drive_b8ef1da9-d76d-44b4-86d4-71c82c888b6f.csv <==
+20230315T103001,28
+
+==> /var/log/de-p1st-monitor/filesystem_3CBA-B4EA.csv <==
+20230315T103001,0.228
+
+==> /var/log/de-p1st-monitor/filesystem_a454430b-dee3-4b6b-8325-f7bdb9435ed1.csv <==
+20230314T231501,0.762
+
+==> /var/log/de-p1st-monitor/filesystem_b8ef1da9-d76d-44b4-86d4-71c82c888b6f.csv <==
+20230315T103001,0.034
+
+==> /var/log/de-p1st-monitor/filesystem_c385a436-0288-486f-a2b9-c64c2db667e7.csv <==
+20230315T103001,0.374
+
+==> /var/log/de-p1st-monitor/memory.csv <==
+20230315T103001,4127,15329
+
+==> /var/log/de-p1st-monitor/net_enp0s31f6.csv <==
+20230315T103001,69366974632,58725303985,20230304T173014
+
+==> /var/log/de-p1st-monitor/swap.csv <==
+20230315T103001,25,4095
+
+==> /var/log/de-p1st-monitor/temp_coretemp_Core 0.csv <==
+20230315T103001,26.0
+
+==> /var/log/de-p1st-monitor/temp_coretemp_Core 1.csv <==
+20230315T103001,34.0
+
+==> /var/log/de-p1st-monitor/temp_coretemp_Package id 0.csv <==
+20230315T103001,35.0
+```
+
+## Plots
+
+### Creating plots with graph-cli
+
+1) Export and fetch data
+
+```shell
+ssh_target=rootnas
+dst=~/de-p1st-monitor-"${ssh_target}"
+files="${dst}".files
+
+# Export .csv files on SSH target and save list of exported files to $files.
+ssh "${ssh_target}" 'de-p1st-monitor --export' > "${files}"
+
+rm -rf "${dst}"
+mkdir -p "${dst}"
+
+rsync --checksum --archive --progress --human-readable --delete \
+  --files-from="${files}" "${ssh_target}":/ "${dst}"
+mv "${dst}"/var/log/de-p1st-monitor/* "${dst}"
+rm -r "${dst}"/var "${files}"
+
+cd "${dst}"
+```
+
+2) Install (python) `graph-cli`
+
+```shell
+python -m venv ~/de-p1st-monitor.venv
+source ~/de-p1st-monitor.venv/bin/activate
+pip install graph-cli
+```
+
+3) Create plots
+
+Create one plot for each .csv file:
+
+```shell
+sample_duration=4H
+
+for file in *.csv; do
+  graph "${file}" -x 1 --resample "${sample_duration}" --figsize 1600x1000 -o "${file}".resample-"${sample_duration}"-mean.png || {
+    echo "Error while processing ${file}"
+  }
+done
+
+for file in {swap,memory}.csv {temp_,drive_,net_,cpu_,filesystem_}*.csv; do
+  graph "${file}" -x 1 --resample "${sample_duration}" --resample-action max --figsize 1600x1000 -o "${file}".resample-"${sample_duration}"-max.png || {
+    echo "Error while processing ${file}"
+  }
+done
+```
+
+4) Optionally, create more plots
+
+Some self-explaining examples:
+
+```shell
+# x and y axis by column name
+graph cpu_1min.csv -x 'datetime#Date' -y 'float#LoadAverage1min' --resample 1H -o cpu_1min_resample-1H.png
+# x and y axis by column number
+graph cpu_1min.csv -x 1 -y 2 --resample 1H -o cpu_1min_resample-1H.png
+# specify x axis; use all other axes for y
+graph cpu_1min.csv -x 1 --resample 1H -o cpu_1min_resample-1H.png
+# increased plot size
+graph cpu_1min.csv -x 1 --resample 1H --figsize 1600x1000 -o cpu_1min_resample-1H.png
+```
+
+```shel
+# resample using sum
+graph net_enp0s31f6.csv.exported.csv -x 1 --resample 1H --resample-action sum --figsize 1600x1000 -o net_enp0s31f6.csv.exported_resample-1H-sum.png
+```
+
+```shel
+# resample using max
+graph cpu_1min.csv -x 1 --resample 1H --resample-action max --figsize 1600x1000 -o cpu_1min_resample-1H-max.png
+```
+
+
+### Example plots
+
+![img](images/cpu_1min.csv.resample-1H.png)
+![img](images/drive_68c349e8-5118-4773-9fd5-5dbad9acee4e.csv.resample-1H.png)
+![img](images/filesystem_c385a436-0288-486f-a2b9-c64c2db667e7.csv.resample-1H.png)
+![img](images/memory.csv.resample-1H.png)
+![img](images/net_enp0s31f6.csv.exported.csv.resample-1H.png)
+![img](images/swap.csv.resample-1H.png)
+![img](images/temp_coretemp_Package%20id%200.csv.resample-1H.png)
--- a/TODO.md
+++ b/TODO.md
@ -0,0 +1,264 @@
+# TODOs
+
+## Public IP address
+
+Logg the public IP address. Reuse `netcup-dns` python functions.
+
+## Rewrite
+
+~~* easier configuration
+~~* easier read/write from/to csv~~
+~~* use classes & objects~~~~
+
+~~* create plots?~~
+
+* Don't send emit warning again, if during previous log a lower warning was emitted
+  * Example:
+    * log1: 30°C OK
+    * log2: 40°C Warning sent
+    * log3: 35°C Still above limit, but don't send warning again as value decreased
+    * log4: 37°C Send another warning: The value increased since last logging
+
+## Use Grafana to visualize metrics
+
+One can use Prometheus + Grafana to collect and visualize server metrics.
+
+> https://geekflare.com/best-open-source-monitoring-software/
+> This list won’t be complete without including two fantastic open-source solutions – Prometheus and Grafana. Its DIY solution where you use Prometheus to scrape the metrics from server, OS, applications and use Grafana to visualize them.
+
+As we do already collect logs, we should do some research on how to
+import data into Grafana.
+
+### Time series
+
+* https://grafana.com/docs/grafana/latest/fundamentals/timeseries/#introduction-to-time-series
+
+E.g. CPU and memory usage, sensor data.
+
+* https://grafana.com/docs/grafana/latest/fundamentals/timeseries/#time-series-databases
+
+A time series database (TSDB) is a database explicitly designed for time series data.
+
+Some supported TSDBs are:
+
+* Graphite
+* InfluxDB
+* Prometheus
+
+### Installation
+
+* https://grafana.com/docs/grafana/latest/setup-grafana/installation/docker/#alpine-image-recommended
+* https://grafana.com/docs/grafana/latest/setup-grafana/installation/docker/#install-official-and-community-grafana-plugins
+
+* https://grafana.com/grafana/plugins/marcusolsson-csv-datasource/?tab=installation
+  * https://grafana.github.io/grafana-csv-datasource/
+* https://grafana.com/grafana/plugins/marcusolsson-json-datasource/?tab=installation
+  * https://grafana.github.io/grafana-json-datasource/
+
+```shell
+sudo docker run --rm \
+  -p 3000:3000 \
+  --name=grafana \
+  -e "GF_INSTALL_PLUGINS=marcusolsson-json-datasource,marcusolsson-csv-datasource" \
+  grafana/grafana-oss
+```
+
+TODO: test csv or json data import tools
+
+## Netdata - Can be exported to Grafana
+
+* https://github.com/netdata/netdata/blob/master/docs/getting-started/introduction.md
+
+## Monit - An existing monitoring service
+
+### General notes and links
+
+* Monit is a widely used service for system monitoring.
+  * OPNsense uses Monit: https://docs.opnsense.org/manual/monit.html
+
+* Short slideshow presentation: https://mmonit.com/monit/#slideshow
+* https://wiki.ubuntuusers.de/Monit/
+
+* Excellent configuration and usage summary in the Arch Linux Wiki: https://wiki.archlinux.org/title/Monit
+
+* Examples
+  * https://mmonit.com/wiki/Monit/ConfigurationExamples
+    * One can use the returncode or stdout of an executed shell script  
+    * https://mmonit.com/wiki/Monit/ConfigurationExamples#HDDHealth
+    ```
+    check program HDD_Health with path "/usr/local/etc/monit/scripts/sdahealth.sh"
+      every 120 cycles
+      if content != "PASSED" then alert
+      # if status > 0 then alert
+      group health
+    ```
+* Documentation
+  * Event queue - Store events (notifications) if mail server is not reachable
+    * https://mmonit.com/monit/documentation/monit.html#Event-queue
+    ```
+    set eventqueue basedir /var/monit
+    ```
+  * https://mmonit.com/monit/documentation/monit.html#SPACE-USAGE-TEST
+  ```
+  check filesystem rootfs with path /
+    if space usage > 90% then alert
+  ```
+  * https://mmonit.com/monit/documentation/monit.html#PROGRAM-STATUS-TEST
+  ```
+  check program myscript with path /usr/local/bin/myscript.sh
+    if status != 0 then alert
+  ```
+  * https://mmonit.com/monit/documentation/monit.html#PROGRAM-OUTPUT-CONTENT-TEST
+  * https://mmonit.com/monit/documentation/monit.html#Link-upload-and-download-bytes
+  ```
+  check network eth0 with interface eth0
+    if upload > 500 kB/s then alert
+    if total downloaded > 1 GB in last 2 hours then alert
+    if total downloaded > 10 GB in last day then alert
+  ```
+
+* https://mmonit.com/monit/documentation/monit.html#MANAGE-YOUR-MONIT-INSTANCES
+
+### Monitoring all your monit instances
+
+* Monit itself does only monitor the current system
+* Multi-server monitoring is a paid extra service called M/Monit :/
+* But there are other open source services for this
+  * https://github.com/monmon-io/monmon#why-did-you-create-monmon
+
+### Setup
+
+Install and start:
+
+```shell
+sudo pacman -S --needed monit lm_sensors smartmontools
+sudo systemctl start monit
+sudo systemctl status monit | grep 'Active: active (running)'
+```
+
+Print default configuration:
+
+```shell
+sudo cat /etc/monitrc | grep -v '^#'
+#=> set daemon 30
+#=>   - A cycle is 30 seconds long.
+#=> set log syslog
+#=>   - We will overwrite this config value later on.
+#=> set httpd port 2812
+#=>   - Only listen on localhost with username admin and pwd monit.
+```
+
+Include `monit.d`:
+
+```shell
+sudo mkdir -p /etc/monit.d/
+! sudo cat /etc/monitrc | grep -q '^include' && echo 'include /etc/monit.d/*' | sudo tee -a /etc/monitrc
+```
+
+Log to file:
+
+```shell
+sudo install -m700 /dev/stdin /etc/monit.d/log <<< 'set log /var/log/monit.log'
+sudo systemctl restart monit
+# tail -f /var/log/monit.log
+```
+
+System:
+
+```shell
+sudo install -m700 /dev/stdin /etc/monit.d/system <<< 'check system $HOST
+  if filedescriptors >= 80% then alert
+  if loadavg (5min) > 2 for 4 cycles then alert
+  if memory usage > 75% for 4 cycles then alert
+  if swap usage > 50% for 4 cycles then alert'
+sudo systemctl restart monit
+```
+
+Filesystem:
+
+```shell
+sudo install -m700 /dev/stdin /etc/monit.d/fs <<< 'check filesystem rootfs with path /
+  if space usage > 80% then alert'
+sudo systemctl restart monit
+```
+
+SSL options:
+
+* https://mmonit.com/monit/documentation/monit.html#SSL-OPTIONS
+
+```shell
+sudo install -m700 /dev/stdin /etc/monit.d/ssl <<< '# Enable certificate verification for all SSL connections
+set ssl options {
+  verify: enable
+}'
+sudo systemctl restart monit
+```
+
+Mailserver, alerts and eventqueue:
+
+* https://mmonit.com/monit/documentation/monit.html#Setting-a-mail-server-for-alert-delivery
+* https://mmonit.com/monit/documentation/monit.html#Setting-an-error-reminder
+* https://mmonit.com/monit/documentation/monit.html#Event-queue
+  * If no mail server is available, Monit can queue events in the local file-system for retry until the mail server recovers.
+  * By default, the queue is disabled and if the alert handler fails, Monit will simply drop the alert message.
+
+```shell
+sudo install -m700 /dev/stdin /etc/monit.d/mail <<< 'set mailserver smtp.mail.de
+  port 465
+  username "langbein@mail.de"
+  password "qiXF6cUgfvSVqd0pAoFTqZEHIcUKzc3n"
+  using SSL
+  with timeout 20 seconds
+
+set mail-format {
+      from: langbein@mail.de
+   subject: $SERVICE - $EVENT at $DATE
+   message: Monit $ACTION $SERVICE at $DATE on $HOST: $DESCRIPTION.
+} 
+
+set alert daniel@systemli.org with reminder on 10 cycles
+
+set eventqueue basedir /var/monit'
+sudo systemctl restart monit
+sudo monit -v  | grep 'Mail'
+```
+
+Test alert:
+
+* https://wiki.ubuntuusers.de/Monit/#E-Mail-Benachrichtigungen-testen
+* It is enough to restart monit. It will send an email that it's state has changed (stopped/started).
+* But if desired, one can also create a test for a non-existing file:
+
+```shell
+sudo install -m700 /dev/stdin /etc/monit.d/alerttest <<< 'check file alerttest with path /.nonexistent.file'
+sudo systemctl restart monit
+```
+
+Example script - run a speedtest:
+
+```shell
+sudo pacman -S --needed speedtest-cli
+sudo install -m700 /dev/stdin /etc/monit.d/speedtest <<< 'check program speedtest with path /usr/bin/speedtest-cli
+  every 120 cycles
+  if status != 0 then alert'
+sudo systemctl restart monit
+```
+
+Check config syntax:
+
+```shell
+sudo monit -t
+```
+
+################## TODOS ##########################
+
+* See Firefox bookmark folder 20230219_monit.
+* Disk health
+* BTRFS balance
+* Save disk usage and temperatures to CSV log file
+  * e.g. by using `check program check-and-log-temp.sh` monit configuration
+  * Or: do checks by monit and every couple minutes run `check program log-system-info.sh`
+
+### Monit behind Nginx
+
+TODO: Nginx reverse proxy with basic authentication.
--- a/cfg/yodaNas.ini
+++ b/cfg/yodaNas.ini
@ -0,0 +1,79 @@
+[logging]
+dir = /var/log/de-p1st-monitor/
+
+[filesystem.1]
+; NVME
+mountpoint = /
+warn_if_above = 0.75
+[filesystem.2]
+; NVME
+mountpoint = /boot
+warn_if_above = 0.75
+[filesystem.3]
+; 12TB1
+uuid = c385a436-0288-486f-a2b9-c64c2db667e7
+warn_if_above = 0.66
+[filesystem.4]
+; 3TB1 and 3TB2
+uuid = a454430b-dee3-4b6b-8325-f7bdb9435ed1
+warn_if_above = 0.85
+unmounted_ok = true
+
+[memory]
+warn_if_above = 0.85
+[swap]
+warn_if_above = 0.85
+
+[cpu1]
+warn_if_above = 3.0
+warn_threshold = 2
+warn_data_range = 2
+[cpu5]
+warn_if_above = 2.0
+warn_threshold = 2
+warn_data_range = 2
+[cpu15]
+warn_if_above = 1.0
+warn_threshold = 2
+warn_data_range = 2
+
+[temp.1]
+sensor = coretemp
+label = Package id 0
+warn_if_above = 60
+[temp.2]
+sensor = coretemp
+label = Core 0
+warn_if_above = 60
+[temp.3]
+sensor = coretemp
+label = Core 1
+warn_if_above = 60
+
+[network.1]
+network_interface = enp0s31f6
+
+[drive.1]
+; NVME /dev/nvme0n1p3
+; TODO NVME 49 warn, 55 limit
+uuid = b8ef1da9-d76d-44b4-86d4-71c82c888b6f
+warn_if_above = 50
+[drive.2]
+; HDD 12TB1
+; TODO HDD 39 warn, 45 limit
+uuid = 68c349e8-5118-4773-9fd5-5dbad9acee4e
+warn_if_above = 40
+[drive.3]
+; HDD 3TB1
+uuid = 20d86155-30d4-404c-95e8-c701cfb16ca5
+warn_if_above = 40
+[drive.4]
+; HDD 3TB2
+uuid = 4651c3f1-e4b8-45aa-a823-df762530a307
+warn_if_above = 40
+
+; TODO digitemp sensor
+;[digitemp_DS9097.1]
+;cfg = /root/.digitemprc
+;sensor_num = 0
+;name = room-temp
--- a/cfg/yodaTux.ini
+++ b/cfg/yodaTux.ini
@ -0,0 +1,79 @@
+[logging]
+; The CSV logfiles are saved in this directory.
+dir = /var/log/de-p1st-monitor/
+
+
+[temp.1]
+; `sensor` and `label` are used to identify one temperature value.
+sensor = k10temp
+label = Tctl
+
+; Warn if temperature is above this value.
+; Unit: °C
+warn_if_above = 80
+
+; Send warning if critical values were reached 2 times during the last 4 logs.
+warn_threshold = 2
+warn_data_range = 4
+
+[temp.2]
+sensor = amdgpu
+label = edge
+warn_if_above = 50
+warn_threshold = 2
+warn_data_range = 4
+
+
+[network.1]
+network_interface = wlan0
+
+
+[memory]
+; Warn if memory usage is above this value.
+; Range: (0.0, 1.0)
+warn_if_above = 0.1
+
+[swap]
+; Warn if swap usage is above this value.
+; Range: (0.0, 1.0)
+warn_if_above = 0.5
+
+
+[cpu1]
+; Warn if CPU load of the last 1 minute is above this value.
+; Range: (0.0, infinite)
+;   `1.0` corresponds to 100% CPU utilisation.
+;   However, there can be more processes in the queue than can be processed.
+;   As a result, the value can go above `1.0`.
+warn_if_above = 0.95
+[cpu5]
+; Warn if CPU load of the last 5 minutes is above this value.
+warn_if_above = 0.85
+[cpu15]
+; Warn if CPU load of the last 15 minutes is above this value.
+warn_if_above = 0.75
+
+
+[filesystem.1]
+; Either `uuid` or `mountpoint` must be given.
+;
+; If both are given but the UUID of the disk mounted at `mountpoint` differs from `uuid`, then an exception is raised.
+uuid = 7fb12542-bd59-4727-9beb-7cf1f79f8293
+mountpoint = /
+
+; If `true` don't log or warn if the filesystem is not found.
+unmounted_ok = true
+
+; Warn if disk usage is above this value.
+; Range: (0.0, 1.0)
+warn_if_above = 0.1
+
+
+[drive.1]
+; Either `uuid` or `device` must be given.
+;uuid =
+device = /dev/nvme0n1p3
+
+; Warn if temperature is above this value.
+; Unit: °C
+warn_if_above = 25
--- a/cron.d/de-p1st-monitor
+++ b/cron.d/de-p1st-monitor
@ -0,0 +1,11 @@
+# Run command every 3min
+# - https://crontab.guru/every-3-minutes
+# `/etc/cron.d/` requires user field
+# - https://unix.stackexchange.com/questions/458713/how-are-files-under-etc-cron-d-used#comment1019389_458715
+# Some users report that files in `/etc/cron.d/` containing `-` are not executed
+# - https://unix.stackexchange.com/questions/296347/crontab-never-running-while-in-etc-cron-d#comment640748_296351
+# PATH is restricted to `/bin:/usr/bin` but `exec-notify` resides in `/usr/local/bin/`
+# - https://serverfault.com/a/449652
+
+PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin/
+*/3 * * * * root exec-notify de-p1st-monitor  > /var/log/de-p1st-monitor.cron 2>&1
--- a/images/cpu_1min.csv.resample-1H.png
+++ b/images/cpu_1min.csv.resample-1H.png
--- a/images/drive_68c349e8-5118-4773-9fd5-5dbad9acee4e.csv.resample-1H.png
+++ b/images/drive_68c349e8-5118-4773-9fd5-5dbad9acee4e.csv.resample-1H.png
--- a/images/filesystem_c385a436-0288-486f-a2b9-c64c2db667e7.csv.resample-1H.png
+++ b/images/filesystem_c385a436-0288-486f-a2b9-c64c2db667e7.csv.resample-1H.png
--- a/images/memory.csv.resample-1H.png
+++ b/images/memory.csv.resample-1H.png
--- a/images/net_enp0s31f6.csv.exported.csv.resample-1H.png
+++ b/images/net_enp0s31f6.csv.exported.csv.resample-1H.png
--- a/images/swap.csv.resample-1H.png
+++ b/images/swap.csv.resample-1H.png
--- a/images/temp_coretemp_Package
+++ b/images/temp_coretemp_Package
--- a/packaging/PKGBUILD
+++ b/packaging/PKGBUILD
@ -0,0 +1,56 @@
+# Maintainer: Daniel Langbein < daniel [ at ] systemli [ dot ] org >
+
+# This PKGBUILD is based on the instructions from the Arch Linux wiki:
+# https://wiki.archlinux.org/title/Python_package_guidelines
+
+_name=de-p1st-monitor
+pkgname="python-$_name-git"
+pkgver=r202.f3f2f46
+pkgrel=1
+pkgdesc='periodically monitor and warn'
+arch=(any)
+url="https://git.privacy1st.de/langfingaz/$_name"
+license=('custom:BSD-3-Clause-Clear-License')
+
+provides=(de-p1st-monitor)
+depends=(python exec-notify)
+makedepends=(git python-build python-installer python-wheel)
+optdepends=('python-psutil: CPU, memory, network monitoring'
+            'digitemp: USB temperature sensor'
+            'smartmontools: disk temperature monitoring')
+
+source=("git+https://git.privacy1st.de/langfingaz/$_name.git")
+b2sums=(SKIP)
+
+# If there are no tags then use number of revisions since beginning of the history:
+# https://wiki.archlinux.org/title/VCS_package_guidelines
+pkgver() {
+    cd "$_name"
+    printf "r%s.%s" "$(git rev-list --count HEAD)" "$(git rev-parse --short=7 HEAD)"
+}
+
+prepare() {
+    git -C "$srcdir/$_name" clean -dfx
+}
+
+build() {
+    # cd "$_name-$pkgver"
+    cd "$_name"
+    python -m build --wheel --no-isolation
+}
+
+package() {
+    # cd "$_name-$pkgver"
+    cd "$_name"
+    python -m installer --destdir="$pkgdir" dist/*.whl
+}
+
+check(){
+    cd "$srcdir/$_name"
+
+    # For nosetests
+    # nosetests
+
+    # For pytest
+    # pytest
+}
--- a/pyproject.toml
+++ b/pyproject.toml
@ -0,0 +1,8 @@
+# https://packaging.python.org/tutorials/packaging-projects/#creating-pyproject-toml
+
+[build-system]
+requires = [
+    "setuptools>=42",
+    "wheel"
+]
+build-backend = "setuptools.build_meta"
--- a/requirements.txt
+++ b/requirements.txt
@ -0,0 +1 @@
+psutil>=5.9
--- a/research/AKCP
+++ b/research/AKCP
--- a/Population/bibtext.txt
+++ b/Population/bibtext.txt
@ -0,0 +1,9 @@
+@inproceedings{32774,
+title	= {Failure Trends in a Large Disk Drive Population},
+author	= {Eduardo Pinheiro and Wolf-Dietrich Weber and Luiz André Barroso},
+year	= {2007},
+booktitle	= {5th USENIX Conference on File and Storage Technologies (FAST 2007)},
+pages	= {17-29}
+}
+
+
--- a/Population/paper.pdf
+++ b/Population/paper.pdf
--- a/Population/paper.xopp
+++ b/Population/paper.xopp
--- a/setup.cfg
+++ b/setup.cfg
@ -0,0 +1,35 @@
+; setup.cfg is the configuration file for setuptools.
+; https://packaging.python.org/tutorials/packaging-projects/#configuring-metadata
+
+[metadata]
+name = de.p1st.monitor
+version = 0.8.0
+author = Daniel Langbein
+author_email = daniel@systemli.org
+description = periodically monitor and warn
+long_description = file: README.md
+long_description_content_type = text/markdown
+url = https://git.privacy1st.de/langfingaz/de-p1st-monitor
+project_urls =
+    Bug Tracker = https://git.privacy1st.de/langfingaz/de-p1st-monitor/issues
+
+; https://pypi.org/classifiers/
+classifiers =
+    Development Status :: 4 - Beta
+    Programming Language :: Python :: 3
+    ; License :: BSD 3-Clause Clear License
+    Operating System :: Unix
+
+[options]
+package_dir =
+    = src
+packages = find:
+python_requires = >=3.6.9
+
+[options.packages.find]
+where = src
+
+[options.entry_points]
+; https://setuptools.readthedocs.io/en/latest/userguide/entry_point.html
+console_scripts=
+    de-p1st-monitor = de.p1st.monitor.main:main
--- a/setup.py
+++ b/setup.py
@ -0,0 +1,4 @@
+# This file is required for `pip install` on Ubuntu 18.04.
+# It loads `setup.cfg`.
+from setuptools import setup
+setup()
--- a/src/de/init.py
+++ b/src/de/init.py
--- a/src/de/p1st/init.py
+++ b/src/de/p1st/init.py
--- a/src/de/p1st/monitor/init.py
+++ b/src/de/p1st/monitor/init.py
--- a/src/de/p1st/monitor/cfg/init.py
+++ b/src/de/p1st/monitor/cfg/init.py
--- a/src/de/p1st/monitor/cfg/loggers.py
+++ b/src/de/p1st/monitor/cfg/loggers.py
@ -0,0 +1,106 @@
+import configparser
+from pathlib import Path
+
+from de.p1st.monitor.cfg.singleton import get_cfg
+from de.p1st.monitor.logger_ex import LoggerArgEx
+from de.p1st.monitor.loggers.cpu import CPULogger1, CPULogger5, CPULogger15
+from de.p1st.monitor.loggers.drive import DriveLogger
+from de.p1st.monitor.loggers.filesystem import FilesystemLogger
+from de.p1st.monitor.loggers.memory import MemoryLogger
+from de.p1st.monitor.loggers.network import NetworkLogger
+from de.p1st.monitor.loggers.swap import SwapLogger
+from de.p1st.monitor.loggers.temp import TempLogger
+from de.p1st.monitor.logger import Logger
+
+def get_or_raise(cfg: configparser.SectionProxy, key: str) -> str:
+    if key in cfg:
+        return cfg[key]
+    else:
+        raise LoggerArgEx(f'Missing key {key} in section {cfg.name}')
+
+def get_loggers() -> tuple[list[Logger], list[LoggerArgEx]]:
+    def temp(cfg: configparser.SectionProxy) -> Logger:
+        sensor = get_or_raise(cfg, 'sensor')
+        label = get_or_raise(cfg, 'label')
+        warn_if_above = float(cfg['warn_if_above']) if 'warn_if_above' in cfg else None
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return TempLogger(sensor, label, warn_if_above, warn_threshold, warn_data_range)
+    def cpu1(cfg: configparser.SectionProxy) -> Logger:
+        warn_if_above = float(cfg['warn_if_above']) if 'warn_if_above' in cfg else None
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return CPULogger1(warn_if_above, warn_threshold, warn_data_range)
+
+    def cpu5(cfg: configparser.SectionProxy) -> Logger:
+        warn_if_above = float(cfg['warn_if_above']) if 'warn_if_above' in cfg else None
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return CPULogger5(warn_if_above, warn_threshold, warn_data_range)
+
+    def cpu15(cfg: configparser.SectionProxy) -> Logger:
+        warn_if_above = float(cfg['warn_if_above']) if 'warn_if_above' in cfg else None
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return CPULogger15(warn_if_above, warn_threshold, warn_data_range)
+
+    def net(cfg: configparser.SectionProxy) -> Logger:
+        network_interface = get_or_raise(cfg, 'network_interface')
+        return NetworkLogger(network_interface)
+
+    def filesystem(cfg: configparser.SectionProxy) -> Logger:
+        uuid = cfg.get('uuid', None)
+        mountpoint = Path(cfg.get('mountpoint')) if 'mountpoint' in cfg else None
+        unmounted_ok = bool(cfg.get('unmounted_ok', 'false'))
+        warn_if_above = float(cfg.get('warn_if_above', '1.0'))
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return FilesystemLogger(uuid, mountpoint, unmounted_ok, warn_if_above, warn_threshold, warn_data_range)
+
+    def drive(cfg: configparser.SectionProxy) -> Logger:
+        uuid = cfg.get('uuid', None)
+        device = Path(cfg.get('device')) if 'device' in cfg else None
+        warn_if_above = int(cfg['warn_if_above']) if 'warn_if_above' in cfg else None
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return DriveLogger(uuid, device, warn_if_above, warn_threshold, warn_data_range)
+
+    def memory(cfg: configparser.SectionProxy) -> Logger:
+        warn_if_above = float(cfg.get('warn_if_above', '1.0'))
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return MemoryLogger(warn_if_above, warn_threshold, warn_data_range)
+    def swap(cfg: configparser.SectionProxy) -> Logger:
+        warn_if_above = float(cfg.get('warn_if_above', '1.0'))
+        warn_threshold = int(cfg.get('warn_threshold', '1'))
+        warn_data_range = int(cfg.get('warn_data_range', '1'))
+        return SwapLogger(warn_if_above, warn_threshold, warn_data_range)
+
+
+    mapping = {
+        'temp': temp,
+        'cpu1': cpu1,
+        'cpu5': cpu5,
+        'cpu15': cpu15,
+        'network': net,
+        'filesystem': filesystem,
+        'drive': drive,
+        'memory': memory,
+        'swap': swap,
+    }
+
+    loggers = []
+    exceptions = []
+    cfg: configparser.ConfigParser = get_cfg()
+    for section_name in cfg.sections():
+        if section_name == 'logging':
+            continue
+        prefix = section_name.split('.', maxsplit=1)[0]
+        try:
+            loggers.append(
+                mapping[prefix](cfg[section_name])
+            )
+        except LoggerArgEx as e:
+            exceptions.append(e)
+
+    return loggers, exceptions
--- a/src/de/p1st/monitor/cfg/logging_dir.py
+++ b/src/de/p1st/monitor/cfg/logging_dir.py
@ -0,0 +1,11 @@
+from pathlib import Path
+
+from de.p1st.monitor.cfg.singleton import get_cfg
+
+
+def logging_dir() -> Path:
+    cfg = get_cfg()
+    default = '/var/log/de-p1st-monitor'
+    if 'logging' not in cfg:
+        return Path(default)
+    return Path(cfg['logging'].get('dir', default))
--- a/src/de/p1st/monitor/cfg/singleton.py
+++ b/src/de/p1st/monitor/cfg/singleton.py
@ -0,0 +1,30 @@
+import configparser
+from pathlib import Path
+
+_cfg: configparser.ConfigParser | None = None
+
+
+def init_cfg(config_file: Path = None):
+    global _cfg
+
+    if _cfg is not None:
+        raise ValueError('already initialized')
+
+    if config_file is None:
+        import socket
+        hostname = socket.gethostname()
+        config_file = Path(f'/etc/de-p1st-monitor/{hostname}.ini')
+
+    if not config_file.exists():
+        raise Exception(f'Configuration file does not exist! {config_file}')
+
+    _cfg = configparser.ConfigParser()
+    _cfg.read(config_file)
+
+
+def get_cfg() -> configparser.ConfigParser:
+    global _cfg
+
+    if _cfg is None:
+        raise ValueError('uninitialized')
+    return _cfg
--- a/src/de/p1st/monitor/csv_util.py
+++ b/src/de/p1st/monitor/csv_util.py
@ -0,0 +1,90 @@
+#!/usr/bin/env python3
+import csv
+from collections import deque
+from pathlib import Path
+
+
+def read(file: Path) -> list[list[str]]:
+    """
+    Returns all rows from the CSV file `file`.
+    """
+    with open(file, newline='') as csvfile:
+        reader = csv.reader(csvfile, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
+        return [row for row in reader]
+
+
+def read_last(file: Path, num_rows: int, skip: int = 0) -> list[list[str]]:
+    """
+    Returns the last `num_rows` from the CSV file `file`.
+
+    :param file:
+    :param num_rows:
+    :param skip: If given, the first `skip` rows are skipped.
+    """
+    with open(file, newline='') as csvfile:
+        reader = csv.reader(csvfile, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
+
+        # Skip the first `skip` rows.
+        for i in range(skip):
+            try:
+                next(reader)
+            except StopIteration:
+                break  # EOF
+
+        # Read all other rows but only keep the last `num_rows` rows.
+        q = deque(reader, num_rows)
+        # Return the last `num_rows` as list.
+        return [row for row in q]
+
+
+def write(file: Path,
+          rows: list[list[str]],
+          header: list[str] = None,
+          create_parent_dirs: bool = True,
+          recreate_file: bool = False) -> None:
+    """
+    Create new .csv file if missing or append to existing .csv file.
+
+    :param file:
+    :param rows: The rows to write as csv table to file.
+    :param header: If given will be inserted as first row into the csv table.
+    :param create_parent_dirs: If `file.parent` does not exist, create it.
+    :param recreate_file: Never append, always recreate the .csv file.
+    """
+    if create_parent_dirs and not file.parent.exists():
+        file.parent.mkdir(parents=True, exist_ok=False)
+    if recreate_file and file.exists():
+        file.unlink(missing_ok=False)
+    if file.exists():
+        append(file, rows)
+    else:
+        if header is not None:
+            rows = [header] + rows
+        create(file, rows)
+
+        text = file.read_text()
+        if text.count('\n') != len(rows) or not text.endswith('\n'):
+            raise Exception(f'Created a new csv file with {len(rows)} rows but it does not have {len(rows)} lines. '
+                            f'Make sure that there are no concurrent writes to this file!')
+
+
+def create(file: Path, rows: list[list[str]]) -> None:
+    with open(file, 'x', newline='') as csvfile:
+        writer = csv.writer(csvfile, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
+        writer.writerows(rows)
+
+
+def append(file: Path, rows: list[list[str]]) -> None:
+    with open(file, 'a', newline='') as csvfile:
+        writer = csv.writer(csvfile, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
+        writer.writerows(rows)
+
+
+def test():
+    file = Path('/var/log/de-p1st-monitor/cpu_avg.csv')
+    data = read_last(file, 4, 10)
+    print(data)
+
+
+if __name__ == '__main__':
+    test()
--- a/src/de/p1st/monitor/datetime_util.py
+++ b/src/de/p1st/monitor/datetime_util.py
@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+from datetime import datetime, timezone
+
+
+def test():
+    dt = datetime.now()
+
+    print('non UTC:')
+    print(dt)
+
+    print('\nUTC:')
+    print(now())
+    print(to_str(now()))
+    print(now_str())
+    print(from_str(to_str(now())))
+
+    print('\nlocalized:')
+    print(dt.tzinfo)
+    dt = dt.replace(tzinfo=timezone.utc)
+    print(dt)
+
+
+def now() -> datetime:
+    return datetime.now(timezone.utc)
+
+
+def now_str() -> str:
+    return to_str(now())
+
+
+def to_str(dt: datetime) -> str:
+    return dt.strftime(fmt())
+
+
+def from_str(dt_str: str) -> datetime:
+    dt = datetime.strptime(dt_str, fmt())
+    return dt.replace(tzinfo=timezone.utc)
+
+
+def fmt() -> str:
+    return '%Y%m%dT%H%M%S'
+
+
+def fmt_len() -> int:
+    return 13
+
+
+if __name__ == '__main__':
+    test()
--- a/src/de/p1st/monitor/exec_capture.py
+++ b/src/de/p1st/monitor/exec_capture.py
@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+import subprocess
+
+
+def execute_capture(command: list[str]) -> tuple[int, str, str]:
+    completed: subprocess.CompletedProcess = subprocess.run(
+        command,
+        capture_output=True,
+        text=True,
+    )
+    return completed.returncode, completed.stdout, completed.stderr
--- a/src/de/p1st/monitor/logger.py
+++ b/src/de/p1st/monitor/logger.py
@ -0,0 +1,230 @@
+from pathlib import Path
+from abc import ABC, abstractmethod
+
+from de.p1st.monitor import csv_util
+from de.p1st.monitor.cfg.logging_dir import logging_dir
+from de.p1st.monitor.string_conversion import to_string, from_string
+from de.p1st.monitor.warn import WarnMessage, WarnLevel
+
+
+# https://www.geeksforgeeks.org/abstract-classes-in-python/
+class Logger(ABC):
+    def __init__(self,
+                 warn_threshold: int = 1,
+                 warn_data_range: int = 1,
+                 warn_if_above: int | float = None,
+                 critical_if_above: int | float = None,
+                 ):
+        self.data: list[any] | None = None
+        # True if the data held by this object is already appended to the logfile.
+        self.logged = False
+
+        self.warn_threshold = warn_threshold
+        self.warn_data_range = warn_data_range
+
+        # Either both variables are given, or both are None
+        if warn_if_above is not None and critical_if_above is not None:
+            assert critical_if_above > warn_if_above
+        else:
+            assert warn_if_above is None and critical_if_above is None
+        self.warn_if_above = warn_if_above
+        self.critical_if_above = critical_if_above
+
+    def export_data(self) -> Path:
+        """
+        This method is intended to be overriden in a subclass!
+
+        With most loggers the `get_log_file()` is ready-to-use.
+        In this case this method simply returns `get_log_file()`.
+
+        But some loggers require postprocessing of that data before it can be used.
+        In this case this method creates a new .csv file and returns it.
+
+        @return: Path to .csv file with ready-to-use data.
+        """
+        return self.get_log_file()
+
+    def check(self) -> WarnMessage:
+        """
+        Checks the latest `self.warn_data_range` datasets for problems using `self.check_data()`.
+
+        If at least `self.warn_threshold` problems are found,
+        then a WarnMessage with the highest reported WarnLevel is returned.
+
+        If at least one WarnLevel is above NORMAL,
+        then a WarnMessage is returned independent of the number of problems.
+        """
+        datasets = self.get_datasets(self.warn_data_range)
+        warnings = [self.check_data(data) for data in datasets]
+        warnings = [warning for warning in warnings
+                    if not warning.level == WarnLevel.NONE]
+
+        if len(warnings) == 0:
+            return WarnMessage(WarnLevel.NONE)
+        # max() must not be called with an empty list.
+        highest_warn_level = max([warning.level for warning in warnings])
+
+        messages: list[str] = [warning.message for warning in warnings]
+        message = f'{len(warnings)} of the last {self.warn_data_range} datasets are above limits:\n\t' \
+                  + '\n\t'.join(messages)
+
+        if highest_warn_level > WarnLevel.NORMAL:
+            return WarnMessage(highest_warn_level, message)
+        if len(warnings) >= self.warn_threshold:
+            return WarnMessage(highest_warn_level, message)
+        return WarnMessage(WarnLevel.NONE)
+
+    @abstractmethod
+    def check_data(self, data: list[any]) -> WarnMessage:
+        """
+        Check the given data for problems.
+        Return a WarnLevel indicating how serious the problems are.
+
+        If there are no problems, return `WarnLevel.NONE`.
+        """
+        raise ValueError('Subclasses must implement this')
+
+    def get_all_datasets(self) -> list[list[any]]:
+        # See also: self.get_datasets()
+
+        if self.get_log_file().exists():
+            # We skip the first row as it is the data schema.
+            raw = csv_util.read(self.get_log_file())[1:]
+            data = [self.get_data_from_row(row) for row in raw]
+        else:
+            data = []
+
+        if not self.logged and self.has_data():
+            data.append(self.get_data())
+
+        return data
+
+    def get_datasets(self, num: int) -> list[list[any]]:
+        """
+        Returns the last `num` datasets (including the current dataset).
+        """
+        if not self.logged and self.has_data():
+            # We will append the current data manually.
+            # Thus, we need to read one less line from the CSV file.
+            read_last = num - 1
+        else:
+            read_last = num
+
+        if self.get_log_file().exists():
+            # Read rows from CSV file.
+            # We skip the first row as it is the data schema.
+            # We keep only the last `read_last` rows.
+            raw = csv_util.read_last(self.get_log_file(), read_last, 1)
+            # Convert from string to data types defined in the data schema.
+            data = [self.get_data_from_row(row) for row in raw]
+        else:
+            data = []
+
+        if not self.logged and self.has_data():
+            # We append the current data.
+            # It has not yet been logged and is therefore not included in the CSV file we just read.
+            data.append(self.get_data())
+
+        return data
+
+    def log(self, skip_if_no_data: bool = False) -> None:
+        """
+        Appends the current data (e.g. temperature of a sensor)
+        to a logfile.
+
+        :param skip_if_no_data: Can be used to do nothing if no data is available. If one is sure to have called update() previously, this can be set to True.
+        :raise Exception: If method is called but no data is available. Please do call update() first to avoid this!
+        """
+        if self.logged:
+            return
+        if skip_if_no_data and not self.has_data():
+            return
+
+        csv_util.write(file=self.get_log_file(), rows=[self.get_data_as_row()], header=self.data_schema())
+        self.logged = True
+
+    def update(self):
+        self.set_data(self.read_data())
+        self.logged = False
+
+    @abstractmethod
+    def read_data(self) -> list[any] | None:
+        """
+        Collects current data (e.g. temperature of a sensor).
+
+        Might return None if sensor is detached / not available.
+
+        :raise LoggerReadEx:
+        """
+        raise ValueError('Subclasses must implement this')
+
+    @abstractmethod
+    def data_schema(self) -> list[str]:
+        """
+        Describes the type and meaning of the elements in self.values().
+
+        Returns a list with elements f'{data-type}#{column-description}'.
+
+        Example:
+            ['datetime#Date', 'float#Disk usage']
+        """
+        raise ValueError('Subclasses must implement this')
+
+    def get_data_from_row(self, data: list[str]) -> list[any]:
+        return [
+            from_string(v, type_str)
+            for v, type_str
+            in zip(data, self.data_type_strs())
+        ]
+
+    def get_data_as_row(self) -> list[str]:
+        """
+        Returns `self.get_data()` as string list that can easily be added as row to a CSV file.
+        """
+        return self.as_row(self.get_data())
+
+    def as_row(self, data: list, data_schema: list[str] = None) -> list[str]:
+        """
+        Returns the given `data` as string list that can easily be added as row to a CSV file.
+        """
+        if data_schema is None:
+            data_schema = self.data_schema()
+        return [
+            to_string(v, type_str)
+            for v, type_str
+            in zip(data, self.data_type_strs(data_schema))
+        ]
+
+    def has_data(self) -> bool:
+        return self.data is not None
+
+    def get_data(self) -> list[any]:
+        """
+        Returns the last data collected by `self.update()`.
+        """
+        if self.has_data():
+            return self.data
+        else:
+            raise ValueError(f'Data has not yet been read. {self.__str__()}')
+
+    def set_data(self, data: list[any] | None):
+        self.data = data
+
+    def data_type_strs(self, data_schema: list[str] = None) -> list[str]:
+        if data_schema is None:
+            data_schema = self.data_schema()
+        return [x.split('#', maxsplit=1)[0] for x in data_schema]
+
+    @abstractmethod
+    def get_log_file(self) -> Path:
+        raise ValueError('Subclasses must implement this')
+
+    @classmethod
+    def get_log_dir(cls) -> Path:
+        return logging_dir()
+
+    def __str__(self) -> str:
+        key_value_strings = [f'classname: {type(self).__name__}']
+        for key, value in vars(self).items():
+            key_value_strings.append(f'{key}: {value}')
+        return ', '.join(key_value_strings)
--- a/src/de/p1st/monitor/logger_ex.py
+++ b/src/de/p1st/monitor/logger_ex.py
@ -0,0 +1,14 @@
+class LoggerReadEx(Exception):
+    """
+    Used by Logger subclasses if
+    - sensor data could not be read
+    """
+    pass
+
+
+class LoggerArgEx(Exception):
+    """
+    Used by Logger subclasses if
+    - Logger object created with illegal arguments
+    """
+    pass
--- a/src/de/p1st/monitor/loggers/init.py
+++ b/src/de/p1st/monitor/loggers/init.py
--- a/src/de/p1st/monitor/loggers/cpu.py
+++ b/src/de/p1st/monitor/loggers/cpu.py
@ -0,0 +1,90 @@
+from pathlib import Path
+from abc import abstractmethod
+from typing import Literal
+
+import psutil
+
+from de.p1st.monitor import datetime_util
+
+from de.p1st.monitor.logger import Logger
+from de.p1st.monitor.warn import WarnMessage, WarnLevel
+
+
+class CPULogger(Logger):
+    def __init__(self,
+                 warn_if_above: float = None,
+                 warn_threshold: int = 1,
+                 warn_data_range: int = 1,
+                 ):
+
+        critical_if_above = warn_if_above * 1.5
+        super().__init__(warn_threshold,
+                         warn_data_range,
+                         warn_if_above,
+                         critical_if_above)
+        self.warn_if_above = warn_if_above
+
+    def check_data(self, data: list[any]) -> WarnMessage:
+        load_avg = data[1]
+        message = f'CPU load avg of last {self.get_load_timespan()} minutes is at {load_avg}'
+
+        if load_avg > self.critical_if_above:
+            return WarnMessage(WarnLevel.HIGH, message)
+        if load_avg > self.warn_if_above:
+            return WarnMessage(WarnLevel.NORMAL, message)
+        return WarnMessage(WarnLevel.NONE)
+
+    def read_data(self) -> list[any] | None:
+        return [
+            datetime_util.now(),
+            self.get_load(self.get_load_timespan())
+        ]
+
+    def data_schema(self) -> list[str]:
+        return [
+            'datetime#Date',
+            f'float#LoadAverage{self.get_load_timespan()}min'
+        ]
+
+    def get_log_file(self) -> Path:
+        return self.get_log_dir() / f'cpu_{self.get_load_timespan()}min.csv'
+
+    @abstractmethod
+    def get_load_timespan(self) ->  Literal[1, 5, 15]:
+        raise ValueError('Subclasses must implement this')
+
+    #
+    # HELPERS
+    #
+
+
+    @staticmethod
+    def get_load(minutes: Literal[1, 5, 15]) -> float:
+        """
+        :param minutes: avg of last 1/5/15 minutes
+        :return: Average CPU load of last 1/5/15 minutes
+        """
+        idx_dict = {
+            1: 0,
+            5: 1,
+            15: 2
+        }
+        idx = idx_dict[minutes]
+
+        # Number of processes in the system run queue averaged over
+        # the last 1, 5, and 15 minutes:
+        # one, five, fifteen = psutil.getloadavg()
+
+        # Load percentage during last 5 minutes.
+        # This value has been tested to be correct on my AMD Ryzen 4800H CPU.
+        return psutil.getloadavg()[idx] / psutil.cpu_count()
+
+class CPULogger1(CPULogger):
+    def get_load_timespan(self) -> Literal[1, 5, 15]:
+        return 1
+class CPULogger5(CPULogger):
+    def get_load_timespan(self) -> Literal[1, 5, 15]:
+        return 5
+class CPULogger15(CPULogger):
+    def get_load_timespan(self) -> Literal[1, 5, 15]:
+        return 15
--- a/src/de/p1st/monitor/loggers/drive.py
+++ b/src/de/p1st/monitor/loggers/drive.py
@ -0,0 +1,108 @@
+import json
+from pathlib import Path
+
+from de.p1st.monitor import datetime_util
+
+from de.p1st.monitor.exec_capture import execute_capture
+from de.p1st.monitor.logger import Logger
+from de.p1st.monitor.logger_ex import LoggerArgEx, LoggerReadEx
+from de.p1st.monitor.warn import WarnLevel, WarnMessage
+
+class BlkidException(Exception):
+    pass
+
+class DriveLogger(Logger):
+    def __init__(self, uuid: str = None,
+                 device: Path = None,
+                 warn_if_above: int = None,
+                 warn_threshold: int = 1,
+                 warn_data_range: int = 1,
+                 ):
+
+        critical_if_above = warn_if_above + 10
+        super().__init__(warn_threshold,
+                         warn_data_range,
+                         warn_if_above,
+                         critical_if_above
+                         )
+
+        if uuid is None and device is None:
+            raise LoggerArgEx('uuid or device required')
+
+        if uuid is None:
+            try:
+                self.uuid = self.get_partition_uuid(device)
+            except BlkidException as e:
+                raise LoggerArgEx(getattr(e, 'message', e))
+        else:
+            self.uuid = uuid
+
+        if device is None:
+            self.device = self.get_partition_path(uuid)
+        else:
+            self.device = device
+
+        self.warn_if_above = warn_if_above
+
+    def check_data(self, data: list[any]) -> WarnMessage:
+        temp = data[1]
+        message = f'Temperature of {self.uuid} ist at {temp}'
+
+        if temp > self.critical_if_above:
+            return WarnMessage(WarnLevel.HIGH, message)
+        if temp > self.warn_if_above:
+            return WarnMessage(WarnLevel.NORMAL, message)
+        return WarnMessage(WarnLevel.NONE)
+
+    def read_data(self)  -> list[any]:
+        return [
+            datetime_util.now(),
+            self.get_temp_from_device(self.device),
+        ]
+
+    def data_schema(self) -> list[str]:
+        return ['datetime#Date', 'int#Temperature']
+
+    def get_log_file(self) -> Path:
+        # self.device might change overtime.
+        # Thus, we use self.uuid to identify a partition.
+        return self.get_log_dir() / f'drive_{self.uuid}.csv'
+
+    #
+    # HELPERS
+    #
+
+    @classmethod
+    def get_partition_path(cls, uuid: str) -> Path:
+        """
+        :return: Partition path, e.g. /dev/sda1
+        """
+        return Path(f'/dev/disk/by-uuid/{uuid}').resolve()
+
+    @classmethod
+    def get_partition_uuid(cls, device: Path) -> str:
+        """
+        :param device: E.g. /dev/sda1
+        :return: UUID of e.g. partition /dev/sda1
+        :raise BlkidException: If UUID could not be determined.
+        """
+        returncode, stdout, stderr = execute_capture(['blkid', '-s', 'UUID', '-o', 'value', f'{device}'])
+
+        if returncode != 0:
+            raise BlkidException(f'blkid failed with returncode {returncode}\nstdout: {stdout}\nstderr: {stderr}')
+
+        return stdout.strip()
+
+    @classmethod
+    def get_temp_from_device(cls, device: Path) -> int:
+        """
+        :param device: For example `/dev/sda` or `/dev/disk/by-uuid/<uuid>`
+        :return: Temperature in celsius
+        """
+        returncode, stdout, stderr = execute_capture(['smartctl', '-j', '-a', f'{device}'])
+
+        if returncode != 0:
+            raise LoggerReadEx(f'smartctl failed with returncode {returncode}\nstdout: {stdout}\nstderr: {stderr}')
+        j = json.loads(stdout)
+
+        return j['temperature']['current']
--- a/src/de/p1st/monitor/loggers/filesystem.py
+++ b/src/de/p1st/monitor/loggers/filesystem.py
@ -0,0 +1,164 @@
+from pathlib import Path
+
+import psutil
+from de.p1st.monitor import datetime_util
+from de.p1st.monitor.exec_capture import execute_capture
+
+from de.p1st.monitor.logger import Logger
+from de.p1st.monitor.logger_ex import LoggerArgEx, LoggerReadEx
+from de.p1st.monitor.warn import WarnLevel, WarnMessage
+
+
+class NotMounted(Exception):
+    pass
+
+
+class FilesystemLogger(Logger):
+    def __init__(self, uuid: str = None,
+                 mountpoint: Path = None,
+                 unmounted_ok: bool = False,
+                 warn_if_above: float = 1.0,
+                 warn_threshold: int = 1,
+                 warn_data_range: int = 1,
+                 ):
+
+        # The space between disk is at `self.warn_if_above` and disk is full at `1.0`.
+        buffer = 1 - warn_if_above
+        critical_if_above = warn_if_above + 0.5 * buffer
+        super().__init__(warn_threshold,
+                         warn_data_range,
+                         warn_if_above,
+                         critical_if_above,
+                         )
+
+        if uuid is None and mountpoint is None:
+            raise LoggerArgEx('uuid or mountpoint required')
+
+        self.uuid = uuid
+        self.mountpoint = mountpoint
+        self.unmounted_ok = unmounted_ok
+        self.warn_if_above = warn_if_above
+
+        self.mounted = True
+
+        #
+        #
+        #
+
+        # If uuid and mountpoint are both specified,
+        # raise warning if unexpected uuid is mounted at mountpoint.
+        if self.mountpoint is not None and self.uuid is not None:
+            try:
+                actual_uuid = self.get_uuid(self.mountpoint)
+                self.mounted = True
+                if self.uuid != actual_uuid:
+                    raise LoggerReadEx(f'Expected {self.uuid} at {self.mountpoint} but got {actual_uuid}')
+            except NotMounted as e:
+                if self.unmounted_ok:
+                    self.mounted = False
+                else:
+                    raise LoggerArgEx(getattr(e, 'message', e))
+
+        # Try to get UUID (if only mountpoint given)
+        if self.uuid is None:
+            try:
+                self.uuid = self.get_uuid(self.mountpoint)
+                self.mounted = True
+            except NotMounted as e:
+                if self.unmounted_ok:
+                    self.mounted = False
+                else:
+                    raise LoggerArgEx(getattr(e, 'message', e))
+
+        # Try to get mountpoint (if only uuid given)
+        if self.mountpoint is None:
+            try:
+                self.mountpoint = self.get_mountpoint(self.uuid)
+                self.mounted = True
+            except NotMounted as e:
+                if self.unmounted_ok:
+                    self.mounted = False
+                else:
+                    raise LoggerReadEx(getattr(e, 'message', e))
+
+    def check_data(self, data: list[any]) -> WarnMessage:
+        if not self.mounted:
+            return WarnMessage(WarnLevel.NONE)
+
+        disk_usage = data[1]
+        message = f'Disk usage of {self.uuid} ist at {disk_usage}'
+
+        if disk_usage > self.critical_if_above:
+            return WarnMessage(WarnLevel.HIGH, message)
+        if disk_usage > self.warn_if_above:
+            return WarnMessage(WarnLevel.NORMAL, message)
+        return WarnMessage(WarnLevel.NONE)
+
+    def read_data(self) -> list[any] | None:
+        if not self.mounted:
+            return None
+
+        disk_usage: float = self.get_disk_usage(self.mountpoint)
+        return [
+            datetime_util.now(),
+            disk_usage,
+        ]
+
+    def data_schema(self) -> list[str]:
+        return ['datetime#Date', 'float#Disk usage']
+
+    def get_log_file(self) -> Path:
+        # The mountpoint of a filesystem might change overtime.
+        # Thus, we use self.uuid to identify a filesystem.
+        return self.get_log_dir() / f'filesystem_{self.uuid}.csv'
+
+    #
+    # HELPERS
+    #
+
+    @classmethod
+    def get_disk_usage(cls, mountpoint: Path) -> float:
+        """
+        :returns: used space / total space
+        """
+        return psutil.disk_usage(str(mountpoint)).percent / 100.0
+
+    @classmethod
+    def get_mountpoint(cls, uuid: str) -> Path:
+        """
+        Throws an error if the corresponding partition is not mounted.
+        """
+
+        partition_list: list[psutil._common.sdiskpart] = psutil.disk_partitions(all=False)
+        partitions: dict[Path, psutil._common.sdiskpart] = {Path(partition.device).resolve(): partition for partition in
+                                                            partition_list}
+
+        partition_path = cls.get_partition_path(uuid)
+        if partition_path not in partitions:
+            raise NotMounted(
+                f'Partition {partition_path} is probably not mounted '
+                f'as it is not in psutil partition list: {partitions}')
+
+        partition = partitions[partition_path]
+        return Path(partition.mountpoint)
+
+    @classmethod
+    def get_uuid(cls, mountpoint: Path) -> str:
+        # Returns the UUID of the device mounted at `/`.
+        # Fails if there is no disk mounted at `/`.
+        #
+        # findmnt / -o UUID -n
+
+        returncode, stdout, stderr = execute_capture(['findmnt', str(mountpoint), '-o', 'UUID', '-n'])
+        if returncode != 0:
+            raise NotMounted(
+                f'No partition mounted at {mountpoint}. Stderr of findmnt: {stderr}')
+
+        return stdout.strip()
+
+    @classmethod
+    def get_partition_path(cls, uuid: str) -> Path:
+        """
+        :return: Partition path, e.g. /dev/sda1
+        """
+        return Path(f'/dev/disk/by-uuid/{uuid}').resolve()
--- a/src/de/p1st/monitor/loggers/memory.py
+++ b/src/de/p1st/monitor/loggers/memory.py
@ -0,0 +1,74 @@
+from pathlib import Path
+
+import psutil
+from de.p1st.monitor import datetime_util
+
+from de.p1st.monitor.logger import Logger
+from de.p1st.monitor.warn import WarnMessage, WarnLevel
+
+
+class MemoryLogger(Logger):
+    def __init__(self,
+                 warn_if_above: float = 1.0,
+                 warn_threshold: int = 1,
+                 warn_data_range: int = 1,
+                 ):
+
+        # The space between memory is at `self.warn_if_above` and memory is full at `1.0`.
+        buffer = 1 - warn_if_above
+        critical_if_above = warn_if_above + 0.5 * buffer
+        super().__init__(warn_threshold,
+                         warn_data_range,
+                         warn_if_above,
+                         critical_if_above)
+        self.warn_if_above = warn_if_above
+
+    def check_data(self, data: list[any]) -> WarnMessage:
+        used_mb = data[1]
+        total_available_mb = data[3]
+        message = f'Memory usage ist at {used_mb} MB of {total_available_mb} MB'
+
+        used = used_mb / total_available_mb
+
+        if used > self.critical_if_above:
+            return WarnMessage(WarnLevel.HIGH, message)
+        if used > self.warn_if_above:
+            return WarnMessage(WarnLevel.NORMAL, message)
+        return WarnMessage(WarnLevel.NONE)
+
+    def read_data(self)  -> list[any]:
+        used_mb, free_mb, available_mb, total_mb = self.get_memory()
+        used_and_cached_mb = total_mb - free_mb
+        total_available_mb = used_mb + available_mb
+        return [
+            datetime_util.now(),
+            used_mb,
+            used_and_cached_mb,
+            total_available_mb,
+        ]
+
+    def data_schema(self) -> list[str]:
+        return ['datetime#Date', 'int#Used memory in MB', 'int#Used and cached in MB', 'int#Total available memory in MB']
+
+    def get_log_file(self) -> Path:
+        return self.get_log_dir() / f'memory.csv'
+
+    #
+    # HELPERS
+    #
+
+    @classmethod
+    def get_memory(cls) -> tuple[int, int, int, int]:
+        """
+        :return: Tuple[used memory in MB, free memory in MB, total memory in MB]. This does not include swap.
+        """
+        mb = 1024 * 1024
+        mem = psutil.virtual_memory()
+
+        # mem.available:
+        #   The memory that can be given instantly to processes,
+        #   excluding swap.
+        # mem.total:
+        #   Total physical memory (exclusive swap).
+        # mem.used + mem.available != mem.total
+        return int(mem.used / mb), int(mem.free / mb), int(mem.available / mb), int(mem.total / mb)
--- a/src/de/p1st/monitor/loggers/network.py
+++ b/src/de/p1st/monitor/loggers/network.py
@ -0,0 +1,113 @@
+import sys
+from datetime import datetime, timezone, timedelta
+from pathlib import Path
+
+import psutil
+
+from de.p1st.monitor import datetime_util, csv_util
+from de.p1st.monitor.logger import Logger
+from de.p1st.monitor.logger_ex import LoggerReadEx
+from de.p1st.monitor.warn import WarnLevel, WarnMessage
+
+
+class NetworkLogger(Logger):
+    def __init__(self, network_interface: str):
+        super().__init__()
+        self.network_interface = network_interface
+
+    def export_data(self) -> Path:
+        data = self.get_all_datasets()
+
+        export_schema = [
+            'datetime#Date',
+            'float#Bytes sent per second',
+            'float#Bytes received per second',
+        ]
+        export_data = []
+        # Append all other rows.
+        for prev_row, curr_row in zip(data[:-1], data[1:]):
+            # if boot time differs -> reboot between data points -> invalid sent/received deltas
+            if prev_row[3] != curr_row[3]:
+                continue
+
+            elapsed_time: timedelta = curr_row[0] - prev_row[0]
+            delta_sent = curr_row[1] - prev_row[1]
+            delta_received = curr_row[2] - prev_row[2]
+
+            if delta_sent < 0 or delta_received < 0:
+                print(f'bytes received/sent counter did overflow after {prev_row[0]}',
+                      file=sys.stderr)
+                continue
+
+            elapsed_seconds = elapsed_time.total_seconds()
+            export_data.append([
+                # datetime#Date
+                prev_row[0] + 0.5 * elapsed_time,
+                # float#Bytes sent per second
+                delta_sent / elapsed_seconds,
+                # float#Bytes received per second
+                delta_received / elapsed_seconds,
+            ])
+
+        export_file = self.get_log_file().parent.joinpath(self.get_log_file().name + '.exported.csv')
+        rows = [self.as_row(export_row, export_schema) for export_row in export_data]
+        csv_util.write(file=export_file, rows=rows, header=export_schema, recreate_file=True)
+        return export_file
+
+    def check_data(self, data: list[any]) -> WarnMessage:
+        return WarnMessage(WarnLevel.NONE)
+
+    def data_schema(self) -> list[str]:
+        return [
+            'datetime#Date',
+            'int#Bytes sent since boot',
+            'int#Bytes received since boot',
+            'datetime#Boot date',
+        ]
+
+    def read_data(self)  -> list[any]:
+        sent, received = self.get_net_usage()
+        return [
+            datetime_util.now(),
+            sent,
+            received,
+            self.get_boot_time(),
+        ]
+
+    def get_log_file(self) -> Path:
+        return self.get_log_dir() / f'net_{self.network_interface}.csv'
+
+    #
+    # HELPERS
+    #
+
+    def get_net_usage(self) -> tuple[int, int]:
+        """
+        Warning: The returned values may overflow if the system is running for a long time.
+
+        :return: bytes sent, bytes received
+        """
+        # noinspection PyTypeChecker
+        nics_data: dict[str, psutil._common.snetio] = psutil.net_io_counters(pernic=True, nowrap=True)
+
+        if self.network_interface not in nics_data:
+            raise LoggerReadEx(f'Network interface {self.network_interface} not found')
+
+        nic_data = nics_data[self.network_interface]
+        return nic_data.bytes_sent, nic_data.bytes_recv
+
+    @classmethod
+    def get_boot_time(cls) -> datetime:
+        epoch_seconds = psutil.boot_time()
+        return datetime.fromtimestamp(epoch_seconds, tz=timezone.utc)
+
+def test():
+    from de.p1st.monitor.cfg.singleton import init_cfg
+    init_cfg()
+
+    logger = NetworkLogger('wlp1s0')
+    logger.update()
+    logger.log()
+
+if __name__ == '__main__':
+    test()
--- a/src/de/p1st/monitor/loggers/swap.py
+++ b/src/de/p1st/monitor/loggers/swap.py
@ -0,0 +1,69 @@
+from pathlib import Path
+
+import psutil
+from de.p1st.monitor import datetime_util
+
+from de.p1st.monitor.logger import Logger
+from de.p1st.monitor.warn import WarnMessage, WarnLevel
+
+
+class SwapLogger(Logger):
+    def __init__(self,
+                 warn_if_above: float = 1.0,
+                 warn_threshold: int = 1,
+                 warn_data_range: int = 1,
+                 ):
+
+        # The space between swap is at `self.warn_if_above` and swap is full at `1.0`.
+        buffer = 1 - warn_if_above
+        critical_if_above = warn_if_above + 0.5 * buffer
+        super().__init__(warn_threshold,
+                         warn_data_range,
+                         warn_if_above,
+                         critical_if_above)
+        self.warn_if_above = warn_if_above
+
+    def check_data(self, data: list[any]) -> WarnMessage:
+        used_mb = data[1]
+        total_mb = data[2]
+        message = f'Swap usage ist at {used_mb} MB of {total_mb} MB'
+
+        if used_mb == 0 and total_mb == 0:
+            # Swap not enabled.
+            return WarnMessage(WarnLevel.NONE)
+
+        usage = used_mb / total_mb
+
+        if usage > self.critical_if_above:
+            return WarnMessage(WarnLevel.HIGH, message)
+        if usage > self.warn_if_above:
+            return WarnMessage(WarnLevel.NORMAL, message)
+        return WarnMessage(WarnLevel.NONE)
+
+    def read_data(self) -> list[any]:
+        used_mb, total_mb = self.get_swap()
+        return [
+            datetime_util.now(),
+            used_mb,
+            total_mb,
+        ]
+
+    def data_schema(self) -> list[str]:
+        return ['datetime#Date', 'int#Used swap in MB', 'int#Total swap in MB']
+
+    def get_log_file(self) -> Path:
+        return self.get_log_dir() / f'swap.csv'
+
+    #
+    # HELPERS
+    #
+
+    @classmethod
+    def get_swap(cls) -> (int, int):
+        """
+        :return: Tuple[used swap in MB, total swap in MB].
+        """
+        mb = 1024 * 1024
+        mem = psutil.swap_memory()
+
+        return int(mem.used / mb), int(mem.total / mb)
--- a/src/de/p1st/monitor/loggers/temp.py
+++ b/src/de/p1st/monitor/loggers/temp.py
@ -0,0 +1,82 @@
+from pathlib import Path
+
+import psutil
+
+from de.p1st.monitor import datetime_util
+from de.p1st.monitor.logger import Logger
+from de.p1st.monitor.logger_ex import LoggerReadEx
+from de.p1st.monitor.warn import WarnMessage, WarnLevel
+
+
+class TempLogger(Logger):
+    def __init__(self, sensor_name: str,
+                 sensor_label: str,
+                 warn_if_above: float = None,
+                 warn_threshold: int = 1,
+                 warn_data_range: int = 1,
+                 ):
+
+        critical_if_above = warn_if_above + 10
+        super().__init__(warn_threshold,
+                         warn_data_range,
+                         warn_if_above,
+                         critical_if_above)
+        self.name = sensor_name
+        self.label = sensor_label
+
+        self.warn_if_above = warn_if_above
+
+    def check_data(self, data: list[any]) -> WarnMessage:
+        temp = data[1]
+        message = f'Temperature of {self.name} {self.label} ist at {temp}'
+
+        if temp > self.critical_if_above:
+            return WarnMessage(WarnLevel.HIGH, message)
+        if temp > self.warn_if_above:
+            return WarnMessage(WarnLevel.NORMAL, message)
+        return WarnMessage(WarnLevel.NONE)
+
+    def read_data(self) -> list[any]:
+        return [
+            datetime_util.now(),
+            self.get_temp()
+        ]
+
+    def data_schema(self) -> list[str]:
+        return [
+            'datetime#Date',
+            'float#Temperature'
+        ]
+
+    def get_log_file(self) -> Path:
+        return self.get_log_dir() / f'temp_{self.name}_{self.label}.csv'
+
+    #
+    # HELPERS
+    #
+
+    def get_temp(self) -> float:
+        """
+        :return: Temperature in celsius
+        """
+        data = psutil.sensors_temperatures(fahrenheit=False)
+        if not self.name in data:
+            raise LoggerReadEx(f'Sensor {self.name} not found')
+        for i in data[self.name]:
+            if i.label == self.label:
+                return i.current
+        raise LoggerReadEx(f'Label {self.label} of sensor {self.name} not found')
+
+
+def test():
+    from de.p1st.monitor.cfg import singleton
+    singleton.init_cfg()
+
+    logger = TempLogger('amdgpu', 'edge', 47, 2, 4)
+    logger.update()
+    logger.log()
+    logger.check().print()
+
+
+if __name__ == '__main__':
+    test()
--- a/src/de/p1st/monitor/main.py
+++ b/src/de/p1st/monitor/main.py
@ -0,0 +1,83 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+import argparse
+import sys
+from pathlib import Path
+
+from de.p1st.monitor.cfg.singleton import init_cfg
+from de.p1st.monitor.cfg.loggers import get_loggers
+from de.p1st.monitor.logger_ex import LoggerReadEx
+
+
+def main():
+    parser = argparse.ArgumentParser(prog='de-p1st-monitor',
+                                     description='Iterates over all config sections. '
+                                                 'For each section the current sensor data is read '
+                                                 'and logged to a .csv file.')
+    parser.add_argument('--config', '-c', default=None, type=Path,
+                        help='Path to .ini configuration file.')
+    parser.add_argument('--export', '-e', default=False, action='store_true',
+                        help='If `True`, export .csv files and print their paths to stdout. '
+                             'No sensor data is logged during this.')
+    # parser.add_argument('--export', '-e', default=False, type=bool,
+    #                     help='If `True`, export .csv files and print their paths to stdout.
+    #                     No sensor data is logged during this.')
+    args = parser.parse_args()
+    init_cfg(args.config)
+
+    if args.export:
+        export()
+    else:
+        log()
+
+
+def export():
+    loggers, logger_arg_exs = get_loggers()
+    if len(logger_arg_exs) > 0:
+        print('\nCONFIGURATION ERROR: Could not instantiate some of the loggers!', file=sys.stderr)
+        print_exs(logger_arg_exs, [f'{n}.' for n in range(1, 1 + len(logger_arg_exs))])
+        exit(1)
+
+    for logger in loggers:
+        export_path: Path = logger.export_data()
+        print(export_path)
+
+
+def log():
+    loggers, logger_arg_exs = get_loggers()
+    logger_read_exs = []
+    logger_warnings = 0
+    for logger_ct, logger in enumerate(loggers, start=1):
+        print(f'Running logger {logger_ct}/{len(loggers)} ...')
+        try:
+            logger.update()
+        except LoggerReadEx as e:
+            logger_read_exs.append(e)
+            continue
+        # After logger.update() there might still be no data
+        #   Example: FilesystemLogger if partition is not mounted (and unmounted_ok is True)
+        logger.log(skip_if_no_data=True)
+        if logger.check().print().is_warning():
+            logger_warnings += 1
+
+    if len(logger_arg_exs) > 0:
+        print('\nCONFIGURATION ERROR: Could not instantiate some of the loggers!', file=sys.stderr)
+        print_exs(logger_arg_exs, [f'{n}.' for n in range(1, 1 + len(logger_arg_exs))])
+    if len(logger_read_exs) > 0:
+        print('\nRUNTIME ERROR: Some loggers could not fetch sensor data!', file=sys.stderr)
+        print_exs(logger_read_exs, [f'{n}.' for n in range(1, 1 + len(logger_read_exs))])
+
+    if len(logger_arg_exs) + len(logger_read_exs) > 0 or logger_warnings > 0:
+        exit(1)
+
+
+def print_exs(exs: list[Exception], headers: list):
+    for e, header in zip(exs, headers):
+        # Indent str(e) with \t
+        body = '\t' + '\n\t'.join(str(e).splitlines())
+
+        print(f'{header}\n{body}', file=sys.stderr)
+
+
+if __name__ == '__main__':
+    main()
--- a/src/de/p1st/monitor/string_conversion.py
+++ b/src/de/p1st/monitor/string_conversion.py
@ -0,0 +1,24 @@
+from typing import Callable
+
+from de.p1st.monitor import datetime_util
+
+
+def data_types() -> dict[str, dict[str, Callable[[any], any]]]:
+    """
+    Returns a dictionary. Its key-value pairs contain the following:
+
+    Key: Name of type.
+    Value: Dict containing to_string and from_string conversion methods, called 'to' and 'from'.
+    """
+    return {
+        'str': {'to': lambda x: x, 'from': lambda x: x},
+        'int': {'to': lambda x: str(x), 'from': lambda x: int(x)},
+        'float': {'to': lambda x: str(x), 'from': lambda x: float(x)},
+        'datetime': {'to': datetime_util.to_str, 'from': datetime_util.from_str},
+    }
+
+def to_string(v: any, type_str: str) -> str:
+    return data_types()[type_str]['to'](v)
+
+def from_string(v: str, type_str: str) -> any:
+    return data_types()[type_str]['from'](v)
--- a/src/de/p1st/monitor/warn.py
+++ b/src/de/p1st/monitor/warn.py
@ -0,0 +1,49 @@
+from __future__ import annotations
+import sys
+from enum import Enum
+from functools import total_ordering
+
+
+# https://docs.python.org/3/library/functools.html#functools.total_ordering
+@total_ordering
+class WarnLevel(Enum):
+    NONE = 0  # Not a warning. Everything is ok.
+    LOW = 1
+    NORMAL = 2
+    HIGH = 3
+
+    def __eq__(self, other):
+        if isinstance(other, WarnLevel):
+            return self.value == other.value
+        return NotImplemented
+
+    def __lt__(self, other):
+        if isinstance(other, WarnLevel):
+            return self.value < other.value
+        return NotImplemented
+
+
+class WarnMessage:
+    def __init__(self, level: WarnLevel, message: str = None):
+        self.level = level
+        self.message = message
+
+    def is_warning(self) -> bool:
+        return self.level > WarnLevel.NONE
+
+    def print(self, default_message: str = 'Warning!') -> WarnMessage:
+        """
+        return: self
+        """
+        message = default_message if self.message is None else self.message
+
+        if self.level == WarnLevel.NONE:
+            pass
+        elif self.level == WarnLevel.LOW:
+            print(message)
+        elif self.level == WarnLevel.NORMAL:
+            print(message, file=sys.stderr)
+        elif self.level == WarnLevel.HIGH:
+            print(f'[CRITICAL] {message}', file=sys.stderr)
+
+        return self