retry get request; use "logging"

.idea/bbb-status.iml

@@ -3,8 +3,9 @@
   <component name="NewModuleRootManager">
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/venv" />
     </content>
-    <orderEntry type="jdk" jdkName="Python 3.8 (xfconf-backup)" jdkType="Python SDK" />
+    <orderEntry type="jdk" jdkName="Python 3.7 (venv37)" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
   </component>
   <component name="PackageRequirementsSettings">

.idea/misc.xml

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.8 (xfconf-backup)" project-jdk-type="Python SDK" />
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.7 (venv37)" project-jdk-type="Python SDK" />
 </project>

docker-compose.yml

@@ -2,7 +2,7 @@ version: '3.7'
 services:
   bbb-status:
     build: .
-    command: ["log"]  # see main.py for available commandline arguments
+    command: ["log-verbose"]  # see main.py for available commandline arguments
     environment:
       - PYTHONPATH=/usr/src/  # pythonpath is required to import from self created modules ("from langfingaz ...")
       - PYTHONUNBUFFERED=1

src/langfingaz/bbbRequest.py

@@ -1,17 +1,27 @@
 import hashlib
+import logging
+
 import requests
+from requests.adapters import HTTPAdapter
+import requests.packages.urllib3.exceptions
+from requests.packages.urllib3.util.retry import Retry
+
 from xml.etree import ElementTree
 
 import langfingaz.util.fileUtil as fileUtil
-import langfingaz.util.util as util
 
 
-def requestMeetingData() -> str:
+def requestMeetingData(maxRetry=0, gracePeriod: int = 1) -> str:
+    """
+    :arg maxRetry: maximum connection retries; if maxRetry=None, then unlimited retires
+    :arg gracePeriod: seconds to wait before retry
+    :return: XML file containing data about currently active BBB meetings
+      See also: https://docs.bigbluebutton.org/dev/api.html#monitoring
+      as well as: https://docs.bigbluebutton.org/dev/api.html#getmeetings
+    """
+
     requestUrl = getRequestUrl()
-    util.debug("starting request for " + requestUrl)
-    response = requests.get(requestUrl)
-    if not response.ok:
-        raise ValueError("error during request, got status code {}".format(response.status_code))
+    response: requests.Response = doGetRequest(requestUrl)
 
     tree = ElementTree.fromstring(response.content)
     if tree.find('returncode').text != 'SUCCESS':
@@ -20,6 +30,37 @@ def requestMeetingData() -> str:
     return str(response.content, encoding=response.encoding)
 
 
+def doGetRequest(requestUrl: str, maxRetries=6) -> requests.Response:
+    """
+    Performs a HTTPS GET request for the given url and does at most maxRetries retries
+    on connection errors.
+
+    :raises requests.exceptions.HTTPError: If status code not 200 (will retry if 502, 503, 504)
+    :raises requests.packages.urllib3.exceptions.MaxRetryError:
+    """
+
+    logLevel = logging.root.level  # https://stackoverflow.com/a/53951759/6334421
+    logging.basicConfig(level=logging.DEBUG)
+
+    # https://stackoverflow.com/a/35636367/6334421
+    # Retry on basic connectivity issues (including DNS lookup failures),
+    # and HTTP status codes of 502, 503 and 504
+    # Grace period increases after each retry.
+    # See also:
+    # - Session: https://requests.readthedocs.io/en/master/user/advanced/
+    s: requests.sessions.Session = requests.Session()
+    retries: Retry = Retry(total=maxRetries, backoff_factor=5, status_forcelist=[502, 503, 504])
+    s.mount('https://', HTTPAdapter(max_retries=retries))
+
+    response: requests.Response = s.get(requestUrl)
+    logging.basicConfig(level=logLevel)
+
+    # raise exception if status conde NOT 200
+    response.raise_for_status()
+
+    return response
+
+
 def getRequestUrl(api_method: str = 'getMeetings', query_string: str = '') -> str:
     url = getUrl()
     api_url = url + "api/"
@@ -48,4 +89,3 @@ def getSecret() -> str:
     if len(secret) <= min_length:
         raise ValueError("secret should be longer than {} characters!".format(min_length))
     return secret
-

src/langfingaz/logMeetingData.py

@@ -14,9 +14,7 @@ def sleepFiveMin(verbose=False):
 
     if verbose:
         print(">> Sleeping for five minutes <<")
-
-    sys.stdout.flush()
-    time.sleep(fiveMinutes)
+    util.sleep(fiveMinutes)
 
 
 def v2(folder: Path = saveData.getDefaultFolder()):

src/langfingaz/main.py

@@ -1,14 +1,14 @@
 #!/usr/bin/python3
 from sys import argv
+import logging
 
 from langfingaz import plotMeetings
 from langfingaz import logMeetingData
-from langfingaz.util import util
 
 
 def main():
     print("=== bbb-status ===")
-    util.debug(str(argv))
+    logging.debug(str(argv))
     print()
 
     usageStr = 'Usage:\n' + argv[0] + ' [log|log-verbose|plot]\n' + \

src/langfingaz/util/util.py

@@ -1,9 +1,9 @@
-BBB_STATUS_DEBUG = True
+import time
 
 
-def debug(message: str):
-    if BBB_STATUS_DEBUG:
-        print(">> " + message)
+def sleep(seconds: float):
+    print(flush=True)  # print newline -> so that all characters of current line get flushed as well
+    time.sleep(seconds)
 
 
 def indentMultilineStr(s: str, indentWith='\t'):