Docker build sometimes produces empty stdout.log

[MakisH]

See comments in #521 (comment)

I have not yet understood under which situations this happens. The relevant code is here:

tutorials/tools/tests/systemtests/Systemtest.py

Lines 374 to 419 in bf312a9

	def _build_docker(self):
	"""
	Builds the docker image
	"""
	logging.debug(f"Building docker image for {self}")
	time_start = time.perf_counter()
	docker_compose_content = self.__get_docker_compose_file()
	with open(self.system_test_dir / "docker-compose.tutorial.yaml", 'w') as file:
	file.write(docker_compose_content)
	stdout_data = []
	stderr_data = []
	try:
	# Execute docker-compose command
	process = subprocess.Popen(['docker',
	'compose',
	'--file',
	'docker-compose.tutorial.yaml',
	'build'],
	stdout=subprocess.PIPE,
	stderr=subprocess.PIPE,
	start_new_session=True,
	cwd=self.system_test_dir)
	try:
	stdout, stderr = process.communicate(timeout=GLOBAL_TIMEOUT)
	except KeyboardInterrupt as k:
	process.kill()
	# process.send_signal(9)
	raise KeyboardInterrupt from k
	except Exception as e:
	logging.critical(
	f"systemtest {self} had serious issues building the docker images via the `docker compose build` command. About to kill the docker compose command. Please check the logs! {e}")
	process.communicate(timeout=SHORT_TIMEOUT)
	process.kill()
	stdout_data.extend(stdout.decode().splitlines())
	stderr_data.extend(stderr.decode().splitlines())
	elapsed_time = time.perf_counter() - time_start
	return DockerComposeResult(process.returncode, stdout_data, stderr_data, self, elapsed_time)
	except Exception as e:
	logging.critical(f"Error executing docker compose build command: {e}")
	elapsed_time = time.perf_counter() - time_start
	return DockerComposeResult(1, stdout_data, stderr_data, self, elapsed_time)

In the same context, it would be nice if the Docker build output was always archived, even in case it succeeds.