git_trace2_event_log.py - tools/repo - Gitiles

 # Copyright (C) 2020 The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.

 """Provide event logging in the git trace2 EVENT format.

 The git trace2 EVENT format is defined at:
 https://www.kernel.org/pub/software/scm/git/docs/technical/api-trace2.html#_event_format
 https://git-scm.com/docs/api-trace2#_the_event_format_target

   Usage:

   git_trace_log = EventLog()
   git_trace_log.StartEvent()
   ...
   git_trace_log.ExitEvent()
   git_trace_log.Write()
 """


 import datetime
 import json
 import os
 import sys
 import tempfile
 import threading

 from git_command import GitCommand, RepoSourceVersion


 class EventLog(object):
   """Event log that records events that occurred during a repo invocation.

   Events are written to the log as a consecutive JSON entries, one per line.
   Entries follow the git trace2 EVENT format.

   Each entry contains the following common keys:
   - event: The event name
   - sid: session-id - Unique string to allow process instance to be identified.
   - thread: The thread name.
   - time: is the UTC time of the event.

   Valid 'event' names and event specific fields are documented here:
   https://git-scm.com/docs/api-trace2#_event_format
   """

   def __init__(self, env=None):
     """Initializes the event log."""
     self._log = []
     # Try to get session-id (sid) from environment (setup in repo launcher).
     KEY = 'GIT_TRACE2_PARENT_SID'
     if env is None:
       env = os.environ

     now = datetime.datetime.utcnow()

     # Save both our sid component and the complete sid.
     # We use our sid component (self._sid) as the unique filename prefix and
     # the full sid (self._full_sid) in the log itself.
     self._sid = 'repo-%s-P%08x' % (now.strftime('%Y%m%dT%H%M%SZ'), os.getpid())
     parent_sid = env.get(KEY)
     # Append our sid component to the parent sid (if it exists).
     if parent_sid is not None:
       self._full_sid = parent_sid + '/' + self._sid
     else:
       self._full_sid = self._sid

     # Set/update the environment variable.
     # Environment handling across systems is messy.
     try:
       env[KEY] = self._full_sid
     except UnicodeEncodeError:
       env[KEY] = self._full_sid.encode()

     # Add a version event to front of the log.
     self._AddVersionEvent()

   @property
   def full_sid(self):
     return self._full_sid

   def _AddVersionEvent(self):
     """Adds a 'version' event at the beginning of current log."""
     version_event = self._CreateEventDict('version')
     version_event['evt'] = "2"
     version_event['exe'] = RepoSourceVersion()
     self._log.insert(0, version_event)

   def _CreateEventDict(self, event_name):
     """Returns a dictionary with the common keys/values for git trace2 events.

     Args:
       event_name: The event name.

     Returns:
       Dictionary with the common event fields populated.
     """
     return {
         'event': event_name,
         'sid': self._full_sid,
         'thread': threading.currentThread().getName(),
         'time': datetime.datetime.utcnow().isoformat() + 'Z',
     }

   def StartEvent(self):
     """Append a 'start' event to the current log."""
     start_event = self._CreateEventDict('start')
     start_event['argv'] = sys.argv
     self._log.append(start_event)

   def ExitEvent(self, result):
     """Append an 'exit' event to the current log.

     Args:
       result: Exit code of the event
     """
     exit_event = self._CreateEventDict('exit')

     # Consider 'None' success (consistent with event_log result handling).
     if result is None:
       result = 0
     exit_event['code'] = result
     self._log.append(exit_event)

   def _GetEventTargetPath(self):
     """Get the 'trace2.eventtarget' path from git configuration.

     Returns:
       path: git config's 'trace2.eventtarget' path if it exists, or None
     """
     path = None
     cmd = ['config', '--get', 'trace2.eventtarget']
     # TODO(https://crbug.com/gerrit/13706): Use GitConfig when it supports
     # system git config variables.
     p = GitCommand(None, cmd, capture_stdout=True, capture_stderr=True,
                    bare=True)
     retval = p.Wait()
     if retval == 0:
       # Strip trailing carriage-return in path.
       path = p.stdout.rstrip('\n')
     elif retval != 1:
       # `git config --get` is documented to produce an exit status of `1` if
       # the requested variable is not present in the configuration. Report any
       # other return value as an error.
       print("repo: error: 'git config --get' call failed with return code: %r, stderr: %r" % (
           retval, p.stderr), file=sys.stderr)
     return path

   def Write(self, path=None):
     """Writes the log out to a file.

     Log is only written if 'path' or 'git config --get trace2.eventtarget'
     provide a valid path to write logs to.

     Logging filename format follows the git trace2 style of being a unique
     (exclusive writable) file.

     Args:
       path: Path to where logs should be written.

     Returns:
       log_path: Path to the log file if log is written, otherwise None
     """
     log_path = None
     # If no logging path is specified, get the path from 'trace2.eventtarget'.
     if path is None:
       path = self._GetEventTargetPath()

     # If no logging path is specified, exit.
     if path is None:
       return None

     if isinstance(path, str):
       # Get absolute path.
       path = os.path.abspath(os.path.expanduser(path))
     else:
       raise TypeError('path: str required but got %s.' % type(path))

     # Git trace2 requires a directory to write log to.

     # TODO(https://crbug.com/gerrit/13706): Support file (append) mode also.
     if not os.path.isdir(path):
       return None
     # Use NamedTemporaryFile to generate a unique filename as required by git trace2.
     try:
       with tempfile.NamedTemporaryFile(mode='x', prefix=self._sid, dir=path,
                                        delete=False) as f:
         # TODO(https://crbug.com/gerrit/13706): Support writing events as they
         # occur.
         for e in self._log:
           # Dump in compact encoding mode.
           # See 'Compact encoding' in Python docs:
           # https://docs.python.org/3/library/json.html#module-json
           json.dump(e, f, indent=None, separators=(',', ':'))
           f.write('\n')
         log_path = f.name
     except FileExistsError as err:
       print('repo: warning: git trace2 logging failed: %r' % err,
             file=sys.stderr)
       return None
     return log_path
	# Copyright (C) 2020 The Android Open Source Project
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.

	"""Provide event logging in the git trace2 EVENT format.

	The git trace2 EVENT format is defined at:
	https://www.kernel.org/pub/software/scm/git/docs/technical/api-trace2.html#_event_format
	https://git-scm.com/docs/api-trace2#_the_event_format_target

	Usage:

	git_trace_log = EventLog()
	git_trace_log.StartEvent()
	...
	git_trace_log.ExitEvent()
	git_trace_log.Write()
	"""


	import datetime
	import json
	import os
	import sys
	import tempfile
	import threading

	from git_command import GitCommand, RepoSourceVersion


	class EventLog(object):
	"""Event log that records events that occurred during a repo invocation.

	Events are written to the log as a consecutive JSON entries, one per line.
	Entries follow the git trace2 EVENT format.

	Each entry contains the following common keys:
	- event: The event name
	- sid: session-id - Unique string to allow process instance to be identified.
	- thread: The thread name.
	- time: is the UTC time of the event.

	Valid 'event' names and event specific fields are documented here:
	https://git-scm.com/docs/api-trace2#_event_format
	"""

	def __init__(self, env=None):
	"""Initializes the event log."""
	self._log = []
	# Try to get session-id (sid) from environment (setup in repo launcher).
	KEY = 'GIT_TRACE2_PARENT_SID'
	if env is None:
	env = os.environ

	now = datetime.datetime.utcnow()

	# Save both our sid component and the complete sid.
	# We use our sid component (self._sid) as the unique filename prefix and
	# the full sid (self._full_sid) in the log itself.
	self._sid = 'repo-%s-P%08x' % (now.strftime('%Y%m%dT%H%M%SZ'), os.getpid())
	parent_sid = env.get(KEY)
	# Append our sid component to the parent sid (if it exists).
	if parent_sid is not None:
	self._full_sid = parent_sid + '/' + self._sid
	else:
	self._full_sid = self._sid

	# Set/update the environment variable.
	# Environment handling across systems is messy.
	try:
	env[KEY] = self._full_sid
	except UnicodeEncodeError:
	env[KEY] = self._full_sid.encode()

	# Add a version event to front of the log.
	self._AddVersionEvent()

	@property
	def full_sid(self):
	return self._full_sid

	def _AddVersionEvent(self):
	"""Adds a 'version' event at the beginning of current log."""
	version_event = self._CreateEventDict('version')
	version_event['evt'] = "2"
	version_event['exe'] = RepoSourceVersion()
	self._log.insert(0, version_event)

	def _CreateEventDict(self, event_name):
	"""Returns a dictionary with the common keys/values for git trace2 events.

	Args:
	event_name: The event name.

	Returns:
	Dictionary with the common event fields populated.
	"""
	return {
	'event': event_name,
	'sid': self._full_sid,
	'thread': threading.currentThread().getName(),
	'time': datetime.datetime.utcnow().isoformat() + 'Z',
	}

	def StartEvent(self):
	"""Append a 'start' event to the current log."""
	start_event = self._CreateEventDict('start')
	start_event['argv'] = sys.argv
	self._log.append(start_event)

	def ExitEvent(self, result):
	"""Append an 'exit' event to the current log.

	Args:
	result: Exit code of the event
	"""
	exit_event = self._CreateEventDict('exit')

	# Consider 'None' success (consistent with event_log result handling).
	if result is None:
	result = 0
	exit_event['code'] = result
	self._log.append(exit_event)

	def _GetEventTargetPath(self):
	"""Get the 'trace2.eventtarget' path from git configuration.

	Returns:
	path: git config's 'trace2.eventtarget' path if it exists, or None
	"""
	path = None
	cmd = ['config', '--get', 'trace2.eventtarget']
	# TODO(https://crbug.com/gerrit/13706): Use GitConfig when it supports
	# system git config variables.
	p = GitCommand(None, cmd, capture_stdout=True, capture_stderr=True,
	bare=True)
	retval = p.Wait()
	if retval == 0:
	# Strip trailing carriage-return in path.
	path = p.stdout.rstrip('\n')
	elif retval != 1:
	# `git config --get` is documented to produce an exit status of `1` if
	# the requested variable is not present in the configuration. Report any
	# other return value as an error.
	print("repo: error: 'git config --get' call failed with return code: %r, stderr: %r" % (
	retval, p.stderr), file=sys.stderr)
	return path

	def Write(self, path=None):
	"""Writes the log out to a file.

	Log is only written if 'path' or 'git config --get trace2.eventtarget'
	provide a valid path to write logs to.

	Logging filename format follows the git trace2 style of being a unique
	(exclusive writable) file.

	Args:
	path: Path to where logs should be written.

	Returns:
	log_path: Path to the log file if log is written, otherwise None
	"""
	log_path = None
	# If no logging path is specified, get the path from 'trace2.eventtarget'.
	if path is None:
	path = self._GetEventTargetPath()

	# If no logging path is specified, exit.
	if path is None:
	return None

	if isinstance(path, str):
	# Get absolute path.
	path = os.path.abspath(os.path.expanduser(path))
	else:
	raise TypeError('path: str required but got %s.' % type(path))

	# Git trace2 requires a directory to write log to.

	# TODO(https://crbug.com/gerrit/13706): Support file (append) mode also.
	if not os.path.isdir(path):
	return None
	# Use NamedTemporaryFile to generate a unique filename as required by git trace2.
	try:
	with tempfile.NamedTemporaryFile(mode='x', prefix=self._sid, dir=path,
	delete=False) as f:
	# TODO(https://crbug.com/gerrit/13706): Support writing events as they
	# occur.
	for e in self._log:
	# Dump in compact encoding mode.
	# See 'Compact encoding' in Python docs:
	# https://docs.python.org/3/library/json.html#module-json
	json.dump(e, f, indent=None, separators=(',', ':'))
	f.write('\n')
	log_path = f.name
	except FileExistsError as err:
	print('repo: warning: git trace2 logging failed: %r' % err,
	file=sys.stderr)
	return None
	return log_path