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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at
import codecs
import locale
from threading import Lock
import six
from mozlog.handlers.messagehandler import MessageHandler
from mozlog.structuredlog import log_levels
class BaseHandler(object):
"""A base handler providing message handling facilities to
derived classes.
def __init__(self, inner):
self.message_handler = MessageHandler()
if hasattr(inner, "message_handler"):
class LogLevelFilter(BaseHandler):
"""Handler that filters out messages with action of log and a level
lower than some specified level.
:param inner: Handler to use for messages that pass this filter
:param level: Minimum log level to process
def __init__(self, inner, level):
BaseHandler.__init__(self, inner)
self.inner = inner
self.level = log_levels[level.upper()]
def __call__(self, item):
if item["action"] != "log" or log_levels[item["level"].upper()] <= self.level:
return self.inner(item)
class StreamHandler(BaseHandler):
"""Handler for writing to a file-like object
:param stream: File-like object to write log messages to
:param formatter: formatter to convert messages to string format
_lock = Lock()
def __init__(self, stream, formatter):
BaseHandler.__init__(self, formatter)
assert stream is not None
if six.PY2:
# This is a hack to deal with the case where we are passed a
# StreamWriter (e.g. by mach for stdout). A StreamWriter requires
# the code to handle unicode in exactly the opposite way compared
# to a normal stream i.e. you always have to pass in a Unicode
# object rather than a string object. Cope with that by extracting
# the underlying raw stream.
if isinstance(stream, codecs.StreamWriter):
stream =
self.formatter = formatter = stream
def __call__(self, data):
"""Write a log message.
:param data: Structured log message dictionary."""
formatted = self.formatter(data)
if not formatted:
with self._lock:
if six.PY3:
import io
import mozfile
source_enc = "utf-8"
target_enc = "utf-8"
if isinstance(, io.BytesIO):
target_enc = None
if hasattr(, "encoding"):
target_enc =
if target_enc is None:
target_enc = locale.getpreferredencoding()
if isinstance(, io.StringIO) and isinstance(
formatted, bytes
formatted = formatted.decode(source_enc, "replace")
elif (
isinstance(, io.BytesIO)
or isinstance(, mozfile.NamedTemporaryFile)
) and isinstance(formatted, str):
formatted = formatted.encode(target_enc, "replace")
elif isinstance(formatted, str):
# Suppress eventual surrogates, but keep as string.
# TODO: It is yet unclear how we can end up with
# surrogates here, see comment on patch on bug 1794401.
formatted_bin = formatted.encode(target_enc, "replace")
formatted = formatted_bin.decode(target_enc, "ignore")
# It seems that under Windows we can have cp1252 encoding
# for the output stream and that not all unicode chars map
# well. We just ignore those errors here (they have no
# consequences for the executed tests, anyways).
except (UnicodeEncodeError):
if isinstance(formatted, six.text_type):"utf-8", "replace"))
elif isinstance(formatted, str):
assert False, "Got output from the formatter of an unexpected type"