docs & fix

- improve method docstrings
- some fixes
This commit is contained in:
Daniel Langbein 2023-03-18 15:24:10 +01:00
parent ec472cf5aa
commit 326e3bf5e6
9 changed files with 116 additions and 62 deletions

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@ -7,6 +7,16 @@ def test():
class DataUnitConverter:
"""
A class to convert between data units.
Example: 1.000.000 B == 1 MB
The main purpose is to convert a number with many digits
to a "larger" unit so that the number is shorter
and more readable.
"""
class DataUnit(Enum):
B = 'B'
KB = 'KB'

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@ -4,6 +4,10 @@ import subprocess
def execute_capture(command: list[str]) -> tuple[int, str, str]:
"""
:param command: Executes the given `command` in a subprocess.
:return: (returncode, stdout, stderr)
"""
completed: subprocess.CompletedProcess = subprocess.run(
command,
capture_output=True,

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@ -16,7 +16,16 @@ def execute_consume_chunks(command: list[str],
handle_chunks: Callable[[Queue.put], None],
) -> int:
"""
Local chunks are deleted after they are fed to stdin of subprocess.
The `command` is executed in a subprocess.
`handle_chunks` is executed in a separate thread.
After `handle_chunks` has saved a new chunk,
the path of the saved chunk is added to a `Queue`.
For each chunk that has been added to the `Queue`, we
- read the chunk from disk
- write the chunk to the stdin of the subprocess
- and delete the chunk
:param command:
:param handle_chunks: Has one parameter, `queue_put`. `handle_chunks` must call queue_put.(chunk_path, last_chunk) for each saved chunk.

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@ -7,37 +7,6 @@ import subprocess
from typing import AnyStr, IO
class _Assert:
@staticmethod
def true(a):
if not a:
raise ValueError(f'Expected a to be true: {a}')
@staticmethod
def equal(a, b):
if a != b:
raise ValueError(f'Expected a and b to be equal: {a}, {b}')
def _read_output(str_pipe: IO[AnyStr],
queue_put: Queue.put,
list_append: list.append,
prefix: str = ''):
line: str
for line in str_pipe:
queue_put(f'{prefix}{line}')
list_append(line)
# TODO: Has this any effect?
# str_pipe.close()
def _write_output(queue_get: Queue.get):
# Take items out of queue until taken item is None.
for line in iter(queue_get, None):
sys.stdout.write(line)
# Goal: We want to **capture** and **print** stdout/stderr while running the command.
#
#
@ -79,7 +48,8 @@ def execute_print_capture(command: list[str], encoding='UTF-8') -> tuple[int, st
"""
Executes the given command.
Stdout and stderr are printed in real time.
The stdout and stderr are printed in real time
and returned after the command has finished.
:param command: Command to execute, e.g. ['ls', '-la', '/home']
:param encoding:
@ -127,3 +97,34 @@ def execute_print_capture(command: list[str], encoding='UTF-8') -> tuple[int, st
t_write.join()
return returncode, ''.join(out), ''.join(err)
class _Assert:
@staticmethod
def true(a):
if not a:
raise ValueError(f'Expected a to be true: {a}')
@staticmethod
def equal(a, b):
if a != b:
raise ValueError(f'Expected a and b to be equal: {a}, {b}')
def _read_output(str_pipe: IO[AnyStr],
queue_put: Queue.put,
list_append: list.append,
prefix: str = ''):
line: str
for line in str_pipe:
queue_put(f'{prefix}{line}')
list_append(line)
# TODO: Has this any effect?
# str_pipe.close()
def _write_output(queue_get: Queue.get):
# Take items out of queue until taken item is None.
for line in iter(queue_get, None):
sys.stdout.write(line)

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@ -14,15 +14,15 @@ def execute_produce_chunks(command: list[str],
chunk_size: int = 1024 * 1024,
) -> int:
"""
Executes the given command in a subprocess.
Executes the given `command` in a subprocess.
Stdout of the subprocess is saved in chunks.
The location of the chunks is determined by `get_chunk_path`.
The stdout of the subprocess is saved in chunks.
The location of the chunks is determined by `get_chunk_path(chunk_no)`.
A separate thread calls `handle_chunk` once a new chunk was saved.
It is the duty of `handle_chunk` to delete processed chunks from disk.
A separate thread calls `handle_chunk(chunk_no, last_chunk)` once a new chunk was saved.
It is the duty of `handle_chunk` to delete the processed chunk.
Stderr of the subprocess is printed to sys.stderr.
The stderr of the subprocess is printed to sys.stderr.
:param command:
:param get_chunk_path:

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@ -13,6 +13,19 @@ def receive_inform(in_pipe: IO[AnyStr],
get_chunk_file: Callable[[Path, int], Path],
) -> None:
"""
Creates a listening UNIX socket at `socket_file`.
Waits for incoming messages `OK` and `EOF` on the socket.
Once a message is received,
the file returned by `get_chunk_file(chunk_file_tmpl, chunk_no)`
is read and then written to `in_pipe`.
If the received message was `EOF`, then the listening loop ends.
If the received message was `OK`, then chunk_no is increased by one and the loop continues.
Finally, the socket is closed.
:param get_chunk_file:
:param in_pipe:
:param chunk_file_tmpl:

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@ -10,30 +10,40 @@ def repeat_until_successful(command: list[str],
retries: int = 0,
retry_delay_seconds: float = 5) -> str:
"""
Executes the given `command`.
Executes the given `command` and returns its stdout.
If an error occurs, it creates a UNIX socket at
`socket_file` and waits for user input.
If the command has failed, it is executed at most `retires` times again, until successful.
Between each retry we wait for `retry_delay_seconds`.
If no more retries are left, a UNIX socket is created at `socket_file`
and we wait for user input.
"""
while True:
returncode: int
out: str
returncode, out, _err = execute_print_capture(command)
stdout: str
returncode, stdout, _stderr = execute_print_capture(command)
# If no error occurred, return stdout of subprocess.
if returncode == 0:
time.sleep(retry_delay_seconds)
return out
return stdout
# Else, an error has occurred.
print(f'\n'
f'Error while executing:\n'
f'\t{command}\n'
f'\tFor details, see above output.')
# If retry attempts are left,
# wait `retry_delay_seconds` and then execute the command again.
if retries > 0:
print('\tRetrying the failed command.'
'\n')
retries = retries - 1
print(f'\tRetrying the failed command in {retry_delay_seconds} seconds.'
f'\n')
time.sleep(retry_delay_seconds)
retries -= 1
continue
# Else, no more retry attempts are left.
# Print message and wait for user input.
print(f'Info:\n'
f'\tPlease fix the above error first. Then continue here:\n'
f'\tsudo pacman -S --needed openbsd-netcat\n'

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@ -14,7 +14,7 @@ def wait_for_message(socket_file: Path,
Closes the UNIX socket.
:returns: The message that was received.
:return: The message that was received.
"""
# INSPIRATION: https://pymotw.com/3/socket/uds.html

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@ -4,6 +4,13 @@ from pathlib import Path
def write_message(socket_file: Path,
message: bytes):
"""
Writes `message` to the UNIX socket `socket_file`.
:param socket_file:
:param message:
:return:
"""
# INSPIRATION: https://pymotw.com/3/socket/uds.html