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Diffstat (limited to 'src/python-systemd/journal.py')
| -rw-r--r-- | src/python-systemd/journal.py | 541 |
1 files changed, 541 insertions, 0 deletions
diff --git a/src/python-systemd/journal.py b/src/python-systemd/journal.py new file mode 100644 index 0000000000..9ef1ede229 --- /dev/null +++ b/src/python-systemd/journal.py @@ -0,0 +1,541 @@ +# -*- Mode: python; coding:utf-8; indent-tabs-mode: nil -*- */ +# +# This file is part of systemd. +# +# Copyright 2012 David Strauss <david@davidstrauss.net> +# Copyright 2012 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> +# Copyright 2012 Marti Raudsepp <marti@juffo.org> +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. +# +# systemd is distributed in the hope that it will be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public License +# along with systemd; If not, see <http://www.gnu.org/licenses/>. + +from __future__ import division + +import sys as _sys +import datetime as _datetime +import uuid as _uuid +import traceback as _traceback +import os as _os +import logging as _logging +if _sys.version_info >= (3,3): + from collections import ChainMap as _ChainMap +from syslog import (LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, + LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG) +from ._journal import __version__, sendv, stream_fd +from ._reader import (_Reader, NOP, APPEND, INVALIDATE, + LOCAL_ONLY, RUNTIME_ONLY, SYSTEM_ONLY, + _get_catalog) +from . import id128 as _id128 + +if _sys.version_info >= (3,): + from ._reader import Monotonic +else: + Monotonic = tuple + +def _convert_monotonic(m): + return Monotonic((_datetime.timedelta(microseconds=m[0]), + _uuid.UUID(bytes=m[1]))) + +def _convert_source_monotonic(s): + return _datetime.timedelta(microseconds=int(s)) + +def _convert_realtime(t): + return _datetime.datetime.fromtimestamp(t / 1000000) + +def _convert_timestamp(s): + return _datetime.datetime.fromtimestamp(int(s) / 1000000) + +if _sys.version_info >= (3,): + def _convert_uuid(s): + return _uuid.UUID(s.decode()) +else: + _convert_uuid = _uuid.UUID + +DEFAULT_CONVERTERS = { + 'MESSAGE_ID': _convert_uuid, + '_MACHINE_ID': _convert_uuid, + '_BOOT_ID': _convert_uuid, + 'PRIORITY': int, + 'LEADER': int, + 'SESSION_ID': int, + 'USERSPACE_USEC': int, + 'INITRD_USEC': int, + 'KERNEL_USEC': int, + '_UID': int, + '_GID': int, + '_PID': int, + 'SYSLOG_FACILITY': int, + 'SYSLOG_PID': int, + '_AUDIT_SESSION': int, + '_AUDIT_LOGINUID': int, + '_SYSTEMD_SESSION': int, + '_SYSTEMD_OWNER_UID': int, + 'CODE_LINE': int, + 'ERRNO': int, + 'EXIT_STATUS': int, + '_SOURCE_REALTIME_TIMESTAMP': _convert_timestamp, + '__REALTIME_TIMESTAMP': _convert_realtime, + '_SOURCE_MONOTONIC_TIMESTAMP': _convert_source_monotonic, + '__MONOTONIC_TIMESTAMP': _convert_monotonic, + 'COREDUMP': bytes, + 'COREDUMP_PID': int, + 'COREDUMP_UID': int, + 'COREDUMP_GID': int, + 'COREDUMP_SESSION': int, + 'COREDUMP_SIGNAL': int, + 'COREDUMP_TIMESTAMP': _convert_timestamp, +} + +_IDENT_LETTER = set('ABCDEFGHIJKLMNOPQRTSUVWXYZ_') + +def _valid_field_name(s): + return not (set(s) - _IDENT_LETTER) + +class Reader(_Reader): + """Reader allows the access and filtering of systemd journal + entries. Note that in order to access the system journal, a + non-root user must be in the `systemd-journal` group. + + Example usage to print out all informational or higher level + messages for systemd-udevd for this boot: + + >>> j = journal.Reader() + >>> j.this_boot() + >>> j.log_level(journal.LOG_INFO) + >>> j.add_match(_SYSTEMD_UNIT="systemd-udevd.service") + >>> for entry in j: + ... print(entry['MESSAGE']) + + See systemd.journal-fields(7) for more info on typical fields + found in the journal. + """ + def __init__(self, flags=0, path=None, converters=None): + """Create an instance of Reader, which allows filtering and + return of journal entries. + + Argument `flags` sets open flags of the journal, which can be one + of, or ORed combination of constants: LOCAL_ONLY (default) opens + journal on local machine only; RUNTIME_ONLY opens only + volatile journal files; and SYSTEM_ONLY opens only + journal files of system services and the kernel. + + Argument `path` is the directory of journal files. Note that + `flags` and `path` are exclusive. + + Argument `converters` is a dictionary which updates the + DEFAULT_CONVERTERS to convert journal field values. Field + names are used as keys into this dictionary. The values must + be single argument functions, which take a `bytes` object and + return a converted value. When there's no entry for a field + name, then the default UTF-8 decoding will be attempted. If + the conversion fails with a ValueError, unconverted bytes + object will be returned. (Note that ValueEror is a superclass + of UnicodeDecodeError). + + Reader implements the context manager protocol: the journal + will be closed when exiting the block. + """ + super(Reader, self).__init__(flags, path) + if _sys.version_info >= (3,3): + self.converters = _ChainMap() + if converters is not None: + self.converters.maps.append(converters) + self.converters.maps.append(DEFAULT_CONVERTERS) + else: + self.converters = DEFAULT_CONVERTERS.copy() + if converters is not None: + self.converters.update(converters) + + def _convert_field(self, key, value): + """Convert value using self.converters[key] + + If `key` is not present in self.converters, a standard unicode + decoding will be attempted. If the conversion (either + key-specific or the default one) fails with a ValueError, the + original bytes object will be returned. + """ + convert = self.converters.get(key, bytes.decode) + try: + return convert(value) + except ValueError: + # Leave in default bytes + return value + + def _convert_entry(self, entry): + """Convert entire journal entry utilising _covert_field""" + result = {} + for key, value in entry.items(): + if isinstance(value, list): + result[key] = [self._convert_field(key, val) for val in value] + else: + result[key] = self._convert_field(key, value) + return result + + def __iter__(self): + """Part of iterator protocol. + Returns self. + """ + return self + + if _sys.version_info >= (3,): + def __next__(self): + """Part of iterator protocol. + Returns self.get_next(). + """ + return self.get_next() + else: + def next(self): + """Part of iterator protocol. + Returns self.get_next(). + """ + return self.get_next() + + def add_match(self, *args, **kwargs): + """Add one or more matches to the filter journal log entries. + All matches of different field are combined in a logical AND, + and matches of the same field are automatically combined in a + logical OR. + Matches can be passed as strings of form "FIELD=value", or + keyword arguments FIELD="value". + """ + args = list(args) + args.extend(_make_line(key, val) for key, val in kwargs.items()) + for arg in args: + super(Reader, self).add_match(arg) + + def get_next(self, skip=1): + """Return the next log entry as a mapping type, currently + a standard dictionary of fields. + + Optional skip value will return the `skip`\-th log entry. + + Entries will be processed with converters specified during + Reader creation. + """ + if super(Reader, self)._next(skip): + entry = super(Reader, self)._get_all() + if entry: + entry['__REALTIME_TIMESTAMP'] = self._get_realtime() + entry['__MONOTONIC_TIMESTAMP'] = self._get_monotonic() + entry['__CURSOR'] = self._get_cursor() + return self._convert_entry(entry) + return dict() + + def get_previous(self, skip=1): + """Return the previous log entry as a mapping type, + currently a standard dictionary of fields. + + Optional skip value will return the -`skip`\-th log entry. + + Entries will be processed with converters specified during + Reader creation. + + Equivalent to get_next(-skip). + """ + return self.get_next(-skip) + + def query_unique(self, field): + """Return unique values appearing in the journal for given `field`. + + Note this does not respect any journal matches. + + Entries will be processed with converters specified during + Reader creation. + """ + return set(self._convert_field(field, value) + for value in super(Reader, self).query_unique(field)) + + def wait(self, timeout=None): + """Wait for a change in the journal. `timeout` is the maximum + time in seconds to wait, or None, to wait forever. + + Returns one of NOP (no change), APPEND (new entries have been + added to the end of the journal), or INVALIDATE (journal files + have been added or removed). + """ + us = -1 if timeout is None else int(timeout * 1000000) + return super(Reader, self).wait(us) + + def seek_realtime(self, realtime): + """Seek to a matching journal entry nearest to `realtime` time. + + Argument `realtime` must be either an integer unix timestamp + or datetime.datetime instance. + """ + if isinstance(realtime, _datetime.datetime): + realtime = float(realtime.strftime("%s.%f")) * 1000000 + return super(Reader, self).seek_realtime(int(realtime)) + + def seek_monotonic(self, monotonic, bootid=None): + """Seek to a matching journal entry nearest to `monotonic` time. + + Argument `monotonic` is a timestamp from boot in either + seconds or a datetime.timedelta instance. Argument `bootid` + is a string or UUID representing which boot the monotonic time + is reference to. Defaults to current bootid. + """ + if isinstance(monotonic, _datetime.timedelta): + monotonic = monotonic.totalseconds() + monotonic = int(monotonic * 1000000) + if isinstance(bootid, _uuid.UUID): + bootid = bootid.get_hex() + return super(Reader, self).seek_monotonic(monotonic, bootid) + + def log_level(self, level): + """Set maximum log `level` by setting matches for PRIORITY. + """ + if 0 <= level <= 7: + for i in range(level+1): + self.add_match(PRIORITY="%d" % i) + else: + raise ValueError("Log level must be 0 <= level <= 7") + + def messageid_match(self, messageid): + """Add match for log entries with specified `messageid`. + + `messageid` can be string of hexadicimal digits or a UUID + instance. Standard message IDs can be found in systemd.id128. + + Equivalent to add_match(MESSAGE_ID=`messageid`). + """ + if isinstance(messageid, _uuid.UUID): + messageid = messageid.get_hex() + self.add_match(MESSAGE_ID=messageid) + + def this_boot(self, bootid=None): + """Add match for _BOOT_ID equal to current boot ID or the specified boot ID. + + If specified, bootid should be either a UUID or a 32 digit hex number. + + Equivalent to add_match(_BOOT_ID='bootid'). + """ + if bootid is None: + bootid = _id128.get_boot().hex + else: + bootid = getattr(bootid, 'hex', bootid) + self.add_match(_BOOT_ID=bootid) + + def this_machine(self, machineid=None): + """Add match for _MACHINE_ID equal to the ID of this machine. + + If specified, machineid should be either a UUID or a 32 digit hex number. + + Equivalent to add_match(_MACHINE_ID='machineid'). + """ + if machineid is None: + machineid = _id128.get_machine().hex + else: + machineid = getattr(machineid, 'hex', machineid) + self.add_match(_MACHINE_ID=machineid) + + +def get_catalog(mid): + if isinstance(mid, _uuid.UUID): + mid = mid.get_hex() + return _get_catalog(mid) + +def _make_line(field, value): + if isinstance(value, bytes): + return field.encode('utf-8') + b'=' + value + else: + return field + '=' + value + +def send(MESSAGE, MESSAGE_ID=None, + CODE_FILE=None, CODE_LINE=None, CODE_FUNC=None, + **kwargs): + r"""Send a message to the journal. + + >>> journal.send('Hello world') + >>> journal.send('Hello, again, world', FIELD2='Greetings!') + >>> journal.send('Binary message', BINARY=b'\xde\xad\xbe\xef') + + Value of the MESSAGE argument will be used for the MESSAGE= + field. MESSAGE must be a string and will be sent as UTF-8 to + the journal. + + MESSAGE_ID can be given to uniquely identify the type of + message. It must be a string or a uuid.UUID object. + + CODE_LINE, CODE_FILE, and CODE_FUNC can be specified to + identify the caller. Unless at least on of the three is given, + values are extracted from the stack frame of the caller of + send(). CODE_FILE and CODE_FUNC must be strings, CODE_LINE + must be an integer. + + Additional fields for the journal entry can only be specified + as keyword arguments. The payload can be either a string or + bytes. A string will be sent as UTF-8, and bytes will be sent + as-is to the journal. + + Other useful fields include PRIORITY, SYSLOG_FACILITY, + SYSLOG_IDENTIFIER, SYSLOG_PID. + """ + + args = ['MESSAGE=' + MESSAGE] + + if MESSAGE_ID is not None: + id = getattr(MESSAGE_ID, 'hex', MESSAGE_ID) + args.append('MESSAGE_ID=' + id) + + if CODE_LINE == CODE_FILE == CODE_FUNC == None: + CODE_FILE, CODE_LINE, CODE_FUNC = \ + _traceback.extract_stack(limit=2)[0][:3] + if CODE_FILE is not None: + args.append('CODE_FILE=' + CODE_FILE) + if CODE_LINE is not None: + args.append('CODE_LINE={:d}'.format(CODE_LINE)) + if CODE_FUNC is not None: + args.append('CODE_FUNC=' + CODE_FUNC) + + args.extend(_make_line(key, val) for key, val in kwargs.items()) + return sendv(*args) + +def stream(identifier, priority=LOG_DEBUG, level_prefix=False): + r"""Return a file object wrapping a stream to journal. + + Log messages written to this file as simple newline sepearted + text strings are written to the journal. + + The file will be line buffered, so messages are actually sent + after a newline character is written. + + >>> stream = journal.stream('myapp') + >>> stream + <open file '<fdopen>', mode 'w' at 0x...> + >>> stream.write('message...\n') + + will produce the following message in the journal:: + + PRIORITY=7 + SYSLOG_IDENTIFIER=myapp + MESSAGE=message... + + Using the interface with print might be more convinient: + + >>> from __future__ import print_function + >>> print('message...', file=stream) + + priority is the syslog priority, one of `LOG_EMERG`, + `LOG_ALERT`, `LOG_CRIT`, `LOG_ERR`, `LOG_WARNING`, + `LOG_NOTICE`, `LOG_INFO`, `LOG_DEBUG`. + + level_prefix is a boolean. If true, kernel-style log priority + level prefixes (such as '<1>') are interpreted. See + sd-daemon(3) for more information. + """ + + fd = stream_fd(identifier, priority, level_prefix) + return _os.fdopen(fd, 'w', 1) + +class JournalHandler(_logging.Handler): + """Journal handler class for the Python logging framework. + + Please see the Python logging module documentation for an + overview: http://docs.python.org/library/logging.html. + + To create a custom logger whose messages go only to journal: + + >>> log = logging.getLogger('custom_logger_name') + >>> log.propagate = False + >>> log.addHandler(journal.JournalHandler()) + >>> log.warn("Some message: %s", detail) + + Note that by default, message levels `INFO` and `DEBUG` are + ignored by the logging framework. To enable those log levels: + + >>> log.setLevel(logging.DEBUG) + + To redirect all logging messages to journal regardless of where + they come from, attach it to the root logger: + + >>> logging.root.addHandler(journal.JournalHandler()) + + For more complex configurations when using `dictConfig` or + `fileConfig`, specify `systemd.journal.JournalHandler` as the + handler class. Only standard handler configuration options + are supported: `level`, `formatter`, `filters`. + + To attach journal MESSAGE_ID, an extra field is supported: + + >>> import uuid + >>> mid = uuid.UUID('0123456789ABCDEF0123456789ABCDEF') + >>> log.warn("Message with ID", extra={'MESSAGE_ID': mid}) + + Fields to be attached to all messages sent through this + handler can be specified as keyword arguments. This probably + makes sense only for SYSLOG_IDENTIFIER and similar fields + which are constant for the whole program: + + >>> journal.JournalHandler(SYSLOG_IDENTIFIER='my-cool-app') + + The following journal fields will be sent: + `MESSAGE`, `PRIORITY`, `THREAD_NAME`, `CODE_FILE`, `CODE_LINE`, + `CODE_FUNC`, `LOGGER` (name as supplied to getLogger call), + `MESSAGE_ID` (optional, see above), `SYSLOG_IDENTIFIER` (defaults + to sys.argv[0]). + """ + + def __init__(self, level=_logging.NOTSET, **kwargs): + super(JournalHandler, self).__init__(level) + + for name in kwargs: + if not _valid_field_name(name): + raise ValueError('Invalid field name: ' + name) + if 'SYSLOG_IDENTIFIER' not in kwargs: + kwargs['SYSLOG_IDENTIFIER'] = _sys.argv[0] + self._extra = kwargs + + def emit(self, record): + """Write record as journal event. + + MESSAGE is taken from the message provided by the + user, and PRIORITY, LOGGER, THREAD_NAME, + CODE_{FILE,LINE,FUNC} fields are appended + automatically. In addition, record.MESSAGE_ID will be + used if present. + """ + try: + msg = self.format(record) + pri = self.mapPriority(record.levelno) + mid = getattr(record, 'MESSAGE_ID', None) + send(msg, + MESSAGE_ID=mid, + PRIORITY=format(pri), + LOGGER=record.name, + THREAD_NAME=record.threadName, + CODE_FILE=record.pathname, + CODE_LINE=record.lineno, + CODE_FUNC=record.funcName, + **self._extra) + except Exception: + self.handleError(record) + + @staticmethod + def mapPriority(levelno): + """Map logging levels to journald priorities. + + Since Python log level numbers are "sparse", we have + to map numbers in between the standard levels too. + """ + if levelno <= _logging.DEBUG: + return LOG_DEBUG + elif levelno <= _logging.INFO: + return LOG_INFO + elif levelno <= _logging.WARNING: + return LOG_WARNING + elif levelno <= _logging.ERROR: + return LOG_ERR + elif levelno <= _logging.CRITICAL: + return LOG_CRIT + else: + return LOG_ALERT |