blob: 314fc26d7409ee3a2b5b03303e514565a8a6065c [file] [log] [blame]
# -*- coding: utf-8 -*-
# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Routines for producing event logs."""
import logging
import re
import os
import threading
import time
import yaml
from uuid import uuid4
import factory_common
from autotest_lib.client.cros import factory
class EventLogException(Exception):
def TimedUuid():
"""Returns a UUID that is roughly sorted by time.
The first 8 hexits are replaced by the current time in 100ths of a
second, mod 2**32. This will roll over once every 490 days, but it
will cause UUIDs to be sorted by time in the vast majority of cases
(handy for ls'ing directories); and it still contains far more than
enough randomness to remain unique.
return ("%08x" % (int(time.time() * 100) & 0xFFFFFFFF) +
def YamlDump(structured_data):
"""Wrap yaml.dump to make calling convention consistent."""
return yaml.dump(structured_data,
def TimeString(unix_time=None):
"""Returns the current time (using UTC) as a string.
The format is like ISO8601 but with milliseconds:
t = unix_time or time.time()
return "%s.%03dZ" % (time.strftime("%Y-%m-%dT%H:%M:%S", time.gmtime(t)),
int((t - int(t)) * 1000))
# TODO(tammo): Replace these definitions references to real canonical
# data, once the corresponding modules move over from the autotest
# repo.
EVENT_LOG_DIR = os.path.join(factory.get_state_root(), "events")
# Path to use to generate a device ID in case none exists (i.e.,
# there is no wlan0 interface).
DEVICE_ID_PATH = os.path.join(EVENT_LOG_DIR, ".device_id")
# Path to use to generate an image ID in case none exists (i.e.,
# this is the first time we're creating an event log).
IMAGE_ID_PATH = os.path.join(EVENT_LOG_DIR, ".image_id")
WLAN0_MAC_PATH = "/sys/class/net/wlan0/address"
PREFIX_RE = re.compile("^[a-zA-Z0-9_\.]+$")
EVENT_NAME_RE = re.compile("^[a-z0-9_]+$")
device_id = None
image_id = None
def GetDeviceId():
"""Returns the device ID.
This is derived from the wlan0 MAC address. If no wlan0 device is
available, one is generated into DEVICE_ID_PATH.
global device_id
if not device_id:
if os.path.exists(path):
device_id = open(path).read().strip()
device_id = str(uuid4())
with open(DEVICE_ID_PATH, "w") as f:
print >>f, device_id
logging.warning('No device ID available: generated %s', device_id)
return device_id
def GetBootId():
"""Returns the boot ID."""
return open("/proc/sys/kernel/random/boot_id", "r").read().strip()
def GetImageId():
"""Returns the image ID.
This is stored in IMAGE_ID_PATH; one is generated if not available.
global image_id
if not image_id:
if os.path.exists(IMAGE_ID_PATH):
image_id = open(IMAGE_ID_PATH).read().strip()
image_id = str(uuid4())
with open(IMAGE_ID_PATH, "w") as f:
print >>f, image_id'No image ID available yet: generated %s', image_id)
return image_id
class EventLog(object):
"""Event logger.
lock: A lock guarding all properties.
file: The file object for logging.
prefix: The prefix for the log file.
seq: The current sequence number.
log_id: The ID of the log file.
def ForAutoTest():
"""Creates an EventLog object for the running autotest."""
path = os.environ.get('CROS_FACTORY_TEST_PATH', 'autotest')
uuid = os.environ.get('CROS_FACTORY_TEST_INVOCATION') or TimedUuid()
return EventLog(path, uuid)
def __init__(self, prefix, log_id=None, defer=True):
"""Creates a new event log file, returning an EventLog instance.
A new file will be created of the form <prefix>-UUID, where UUID is
randomly generated. The file will be initialized with a preamble
that includes the following fields:
device_id - Unique per device (eg, MAC addr).
image_id - Unique each time device is imaged.
Due to the generation of device and image IDs, the creation of the *first*
EventLog object is not thread-safe (i.e., one must be constructed completely
before any others can be constructed in other threads or processes). After
that, construction of EventLogs and all EventLog operations are thread-safe.
prefix: String to identify this category of EventLog, to help
humans differentiate between event log files (since UUIDs all
look the same). If string is not alphanumeric with period and
underscore punctuation, raises ValueError.
log_id: A UUID for the log (or None, in which case TimedUuid() is used)
defer: If True, then the file will not be written until the first
event is logged (if ever).
self.file = None
if not PREFIX_RE.match(prefix):
raise ValueError, "prefix %r must match re %s" % (
prefix, PREFIX_RE.pattern)
self.prefix = prefix
self.seq = 0
self.lock = threading.Lock()
self.log_id = log_id or TimedUuid()
self.filename = "%s-%s" % (prefix, self.log_id)
self.path = os.path.join(EVENT_LOG_DIR, self.filename)'Logging events for %s to %s', self.prefix, self.path)
if os.path.exists(self.path):
raise EventLogException, "Log %s already exists" % self.path
self.opened = False
if not defer:
def Close(self):
"""Closes associated log file."""
with self.lock:
if self.file:
self.file = None
def Log(self, event_name, **kwargs):
"""Writes new event stanza to log file, with consistent metadata.
Appends a stanza contain the following fields to the log:
TIME: Formatted as per TimeString().
SEQ: Monotonically increating counter. The preamble will always
have SEQ=0.
EVENT - From event_name input.
... - Other fields from kwargs.
Stanzas are terminated by "---\n".
event_name: Used to indentify event field. Must be serialized
data, eg string or int.
kwargs: Dict of additional fields for inclusion in the event
stanza. Field keys must be alphanumeric and lowercase. Field
values will be automatically yaml-ified. Other data
types will result in a ValueError.
with self.lock:
self._LogUnlocked(event_name, **kwargs)
def _OpenUnlocked(self):
"""Opens the file and writes the preamble (if not already open).
Requires that the lock has already been acquired.
dir = os.path.dirname(self.path)
if not os.path.exists(dir):
# Maybe someone else tried to create it simultaneously
if not os.path.exists(dir):
if self.opened:
self.opened = True
self.file = open(self.path, "w")
def _LogUnlocked(self, event_name, **kwargs):
"""Same as Log, but requires that the lock has already been acquired.
See Log() for Args and Returns.
if self.file is None:
raise IOError, "cannot append to closed file for prefix %r" % (
if not EVENT_NAME_RE.match(event_name):
raise ValueError, "event_name %r must match %s" % (
event_name, EVENT_NAME_RE.pattern)
for k in kwargs:
if not EVENT_KEY_RE.match(k):
raise ValueError, "key %r must match re %s" % (
k, EVENT_KEY_RE.pattern)
data = {
"EVENT": event_name,
"SEQ": self.seq,
"TIME": TimeString()
self.seq += 1