From 240dcceb101f624acdfeb168d2e62d88e0341a41 Mon Sep 17 00:00:00 2001
From: JustAnotherArchivist <JustAnotherArchivist@users.noreply.github.com>
Date: Sat, 4 Mar 2023 21:44:51 +0000
Subject: [PATCH] Add subprocess wrapper for logging stderr

---
 codearchiver/modules/git.py |  9 +++--
 codearchiver/subprocess.py  | 73 +++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 4 deletions(-)
 create mode 100644 codearchiver/subprocess.py

diff --git a/codearchiver/modules/git.py b/codearchiver/modules/git.py
index b50f6de..7223955 100644
--- a/codearchiver/modules/git.py
+++ b/codearchiver/modules/git.py
@@ -1,4 +1,5 @@
 import codearchiver.core
+import codearchiver.subprocess
 import datetime
 import logging
 import os.path
@@ -34,21 +35,21 @@ class Git(codearchiver.core.Module):
 			return
 
 		logger.info(f'Cloning {self._url} into {directory}')
-		subprocess.run(['git', 'clone', '--verbose', '--mirror', self._url, directory], check = True)
+		codearchiver.subprocess.run_with_log(['git', 'clone', '--verbose', '--mirror', self._url, directory])
 
 		if self._extraBranches:
 			for branch, commit in self._extraBranches.items():
 				logger.info(f'Fetching commit {commit} as {branch}')
-				r = subprocess.run(['git', 'fetch', '--verbose', 'origin', commit], cwd = directory)
+				r = codearchiver.subprocess.run_with_log(['git', 'fetch', '--verbose', '--progress', 'origin', commit], cwd = directory, check = False)
 				if r.returncode == 0:
-					r2 = subprocess.run(['git', 'update-ref', f'refs/codearchiver/{branch}', commit, ''], cwd = directory)
+					r2 = codearchiver.subprocess.run_with_log(['git', 'update-ref', f'refs/codearchiver/{branch}', commit, ''], cwd = directory, check = False)
 					if r2.returncode != 0:
 						logger.error(f'Failed to update-ref refs/codearchiver/{branch} to {commit}')
 				else:
 					logger.error(f'Failed to fetch {commit}')
 
 		logger.info(f'Bundling into {bundle}')
-		subprocess.run(['git', 'bundle', 'create', f'../{bundle}', '--all'], cwd = directory, check = True)
+		codearchiver.subprocess.run_with_log(['git', 'bundle', 'create', '--progress', f'../{bundle}', '--all'], cwd = directory)
 
 		logger.info(f'Removing clone')
 		shutil.rmtree(directory)
diff --git a/codearchiver/subprocess.py b/codearchiver/subprocess.py
new file mode 100644
index 0000000..73d9339
--- /dev/null
+++ b/codearchiver/subprocess.py
@@ -0,0 +1,73 @@
+import logging
+import os
+import select
+import selectors
+import subprocess
+
+
+_logger = logging.getLogger(__name__)
+
+
+def run_with_log(args, *, check = True, input = None, **kwargs):
+	'''
+	Run a command using `subprocess.Popen(args, **kwargs)` and log all its stderr output via `logging`.
+	`check` has the same semantics as on `subprocess.run`, i.e. raises an exception if the process exits non-zero.
+	`input`, if specified, is a `bytes` object that is fed to the subprocess via stdin.
+	`stdin`, `stdout`, and `stderr` kwargs must not be used.
+	Returns a tuple with the process's exit status and its stdout output.
+	'''
+	badKwargs = {'stdin', 'stdout', 'stderr'}.intersection(set(kwargs))
+	if badKwargs:
+		raise ValueError(f'Disallowed kwargs: {", ".join(sorted(badKwargs))}')
+	_logger.info(f'Running subprocess: {args!r}')
+	if input:
+		kwargs['stdin'] = subprocess.PIPE
+	p = subprocess.Popen(args, **kwargs, stdout = subprocess.PIPE, stderr = subprocess.PIPE)
+	sel = selectors.DefaultSelector()
+	if input:
+		sel.register(p.stdin, selectors.EVENT_WRITE)
+	sel.register(p.stdout, selectors.EVENT_READ)
+	sel.register(p.stderr, selectors.EVENT_READ)
+	stdout = []
+	stderrBuf = b''
+	if input:
+		stdinView = memoryview(input)
+		stdinOffset = 0
+		PIPE_BUF = getattr(select, 'PIPE_BUF', 512)
+	while sel.get_map():
+		for key, _ in sel.select():
+			if key.fileobj is p.stdin:
+				try:
+					stdinOffset += os.write(key.fd, stdinView[stdinOffset : stdinOffset + PIPE_BUF])
+				except BrokenPipeError:
+					sel.unregister(key.fileobj)
+					key.fileobj.close()
+				else:
+					if stdinOffset >= len(input):
+						sel.unregister(key.fileobj)
+						key.fileobj.close()
+			else:
+				data = key.fileobj.read1()
+				if not data:
+					sel.unregister(key.fileobj)
+					key.fileobj.close()
+					continue
+				if key.fileobj is p.stderr:
+					stderrBuf += data
+					*lines, stderrBuf = stderrBuf.replace(b'\r', b'\n').rsplit(b'\n', 1)
+					if not lines:
+						continue
+					lines = lines[0].decode('utf-8').split('\n')
+					for line in lines:
+						_logger.info(line)
+				else:
+					stdout.append(data)
+	if stderrBuf:
+		_logger.info(stderrBuf.decode('utf-8'))
+	assert p.poll() is not None
+	if input and stdinOffset < len(input):
+		_logger.warning(f'Could not write all input to the stdin pipe (wanted to write {len(input)} bytes, only wrote {stdinOffset})')
+	_logger.info(f'Process exited with status {p.returncode}')
+	if check and p.returncode != 0:
+		raise subprocess.CalledProcessError(returncode = p.returncode, cmd = args)
+	return (p.returncode, b''.join(stdout).decode('utf-8'))