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# Copyright (C) 2008 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.
"""Logic for tracing repo interactions.
Activated via `repo --trace ...` or `REPO_TRACE=1 repo ...`.
Temporary: Tracing is always on. Set `REPO_TRACE=0` to turn off.
To also include trace outputs in stderr do `repo --trace_to_stderr ...`
"""
import contextlib
import os
import sys
import tempfile
import time
import platform_utils
# Env var to implicitly turn on tracing.
REPO_TRACE = "REPO_TRACE"
# Temporarily set tracing to always on unless user expicitly sets to 0.
_TRACE = os.environ.get(REPO_TRACE) != "0"
_TRACE_TO_STDERR = False
_TRACE_FILE = None
_TRACE_FILE_NAME = "TRACE_FILE"
_MAX_SIZE = 70 # in MiB
_NEW_COMMAND_SEP = "+++++++++++++++NEW COMMAND+++++++++++++++++++"
def IsTraceToStderr():
"""Whether traces are written to stderr."""
return _TRACE_TO_STDERR
def IsTrace():
"""Whether tracing is enabled."""
return _TRACE
def SetTraceToStderr():
"""Enables tracing logging to stderr."""
global _TRACE_TO_STDERR
_TRACE_TO_STDERR = True
def SetTrace():
"""Enables tracing."""
global _TRACE
_TRACE = True
def _SetTraceFile(quiet):
"""Sets the trace file location."""
global _TRACE_FILE
_TRACE_FILE = _GetTraceFile(quiet)
class Trace(contextlib.ContextDecorator):
"""Used to capture and save git traces."""
def _time(self):
"""Generate nanoseconds of time in a py3.6 safe way"""
return int(time.time() * 1e9)
def __init__(self, fmt, *args, first_trace=False, quiet=True):
"""Initialize the object.
Args:
fmt: The format string for the trace.
*args: Arguments to pass to formatting.
first_trace: Whether this is the first trace of a `repo` invocation.
quiet: Whether to suppress notification of trace file location.
"""
if not IsTrace():
return
self._trace_msg = fmt % args
if not _TRACE_FILE:
_SetTraceFile(quiet)
if first_trace:
_ClearOldTraces()
self._trace_msg = f"{_NEW_COMMAND_SEP} {self._trace_msg}"
def __enter__(self):
if not IsTrace():
return self
print_msg = (
f"PID: {os.getpid()} START: {self._time()} :{self._trace_msg}\n"
)
with open(_TRACE_FILE, "a") as f:
print(print_msg, file=f)
if _TRACE_TO_STDERR:
print(print_msg, file=sys.stderr)
return self
def __exit__(self, *exc):
if not IsTrace():
return False
print_msg = (
f"PID: {os.getpid()} END: {self._time()} :{self._trace_msg}\n"
)
with open(_TRACE_FILE, "a") as f:
print(print_msg, file=f)
if _TRACE_TO_STDERR:
print(print_msg, file=sys.stderr)
return False
def _GetTraceFile(quiet):
"""Get the trace file or create one."""
# TODO: refactor to pass repodir to Trace.
repo_dir = os.path.dirname(os.path.dirname(__file__))
trace_file = os.path.join(repo_dir, _TRACE_FILE_NAME)
if not quiet:
print(f"Trace outputs in {trace_file}", file=sys.stderr)
return trace_file
def _ClearOldTraces():
"""Clear the oldest commands if trace file is too big."""
try:
with open(_TRACE_FILE, errors="ignore") as f:
if os.path.getsize(f.name) / (1024 * 1024) <= _MAX_SIZE:
return
trace_lines = f.readlines()
except FileNotFoundError:
return
while sum(len(x) for x in trace_lines) / (1024 * 1024) > _MAX_SIZE:
for i, line in enumerate(trace_lines):
if "END:" in line and _NEW_COMMAND_SEP in line:
trace_lines = trace_lines[i + 1 :]
break
else:
# The last chunk is bigger than _MAX_SIZE, so just throw everything
# away.
trace_lines = []
while trace_lines and trace_lines[-1] == "\n":
trace_lines = trace_lines[:-1]
# Write to a temporary file with a unique name in the same filesystem
# before replacing the original trace file.
temp_dir, temp_prefix = os.path.split(_TRACE_FILE)
with tempfile.NamedTemporaryFile(
"w", dir=temp_dir, prefix=temp_prefix, delete=False
) as f:
f.writelines(trace_lines)
platform_utils.rename(f.name, _TRACE_FILE)