Options of date-parser() parsers
The date-parser() parser has the following options.
format()
| Synopsis: | format(string) |
| Default: |
Description: Specifies the format how syslog-ng OSE should parse the date. You can use the following format elements:
%% PERCENT %a day of the week, abbreviated %A day of the week %b month abbr %B month %c MM/DD/YY HH:MM:SS %C ctime format: Sat Nov 19 21:05:57 1994 %d numeric day of the month, with leading zeros (eg 01..31) %e like %d, but a leading zero is replaced by a space (eg 1..31) %f microseconds, leading 0's, extra digits are silently discarded %D MM/DD/YY %G GPS week number (weeks since January 6, 1980) %h month, abbreviated %H hour, 24 hour clock, leading 0's) %I hour, 12 hour clock, leading 0's) %j day of the year %k hour %l hour, 12 hour clock %L month number, starting with 1 %m month number, starting with 01 %M minute, leading 0's %n NEWLINE %o ornate day of month -- "1st", "2nd", "25th", etc. %p AM or PM %P am or pm (Yes %p and %P are backwards :) %q Quarter number, starting with 1 %r time format: 09:05:57 PM %R time format: 21:05 %s seconds since the Epoch, UCT %S seconds, leading 0's %t TAB %T time format: 21:05:57 %U week number, Sunday as first day of week %w day of the week, numerically, Sunday == 0 %W week number, Monday as first day of week %x date format: 11/19/94 %X time format: 21:05:57 %y year (2 digits) %Y year (4 digits) %Z timezone in ascii. eg: PST %z timezone in format -/+0000
For example, for the date 01/Jan/2016:13:05:05 PST use the following format string: format("%d/%b/%Y:%H:%M:%S %Z")
template()
| Synopsis: | template("${<macroname>}") |
Description: The macro that contains the part of the message that the parser will process. It can also be a macro created by a previous parser of the log path. By default, the parser processes the entire message (${MESSAGE}).
flags()
| Type: | guess-timezone |
| Default: | empty string |
guess-timezone: Attempt to guess the timezone of the message if this information is not available in the message. Works when the incoming message stream is close to real time, and the timezone information is missing from the timestamp. For example:
date-parser(flags(guess-timezone));
time-stamp()
| Synopsis: | stamp | recvd |
| Default: | stamp |
Description: Determines if the parsed date values are treated as sent or received date. If you use time-stamp(stamp), syslog-ng OSE adds the parsed date to the S_ macros (corresponding to the sent date). If you use time-stamp(recvd), syslog-ng OSE adds the parsed date to the R_ macros (corresponding to the received date).
time-zone()
| Synopsis: | time-zone(string) |
| Default: |
Description: If this option is set, syslog-ng OSE assumes that the parsed timestamp refers to the specified timezone. The timezone set in the time-zone() option overrides any timezone information parsed from the timestamp.
The timezone can be specified by using the name, for example, time-zone("Europe/Budapest")), or as the timezone offset in +/-HH:MM format, for example, +01:00). On Linux and UNIX platforms, the valid timezone names are listed under the /usr/share/zoneinfo directory.
Python parser
The Python log parser (available in syslog-ng OSE version
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Python parsers and template functions are available in syslog-ng OSE version
Python destinations and sources are available in syslog-ng OSE version
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Supported Python versions: 2.7
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The Python block must be a top-level block in the syslog-ng OSE configuration file.
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If you store the Python code in a separate Python file and only include it in the syslog-ng OSE configuration file, make sure that the PYTHON_PATH environment variable includes the path to the Python file, and export the PYTHON_PATH environment variable. For example, if you start syslog-ng OSE manually from a terminal and you store your Python files in the /opt/syslog-ng/etc directory, use the following command: export PYTHONPATH=/opt/syslog-ng/etc
In production, when syslog-ng OSE starts on boot, you must configure your startup script to include the Python path. The exact method depends on your operating system. For recent Red Hat Enterprise Linux, Fedora, and CentOS distributions that use systemd, the systemctl command sources the /etc/sysconfig/syslog-ng file before starting syslog-ng OSE. (On openSUSE and SLES, /etc/sysconfig/syslog file.) Append the following line to the end of this file: PYTHONPATH="<path-to-your-python-file>", for example, PYTHONPATH="/opt/syslog-ng/etc"
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The Python object is initiated every time when syslog-ng OSE is started or reloaded.
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The Python block can contain multiple Python functions.
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Using Python code in syslog-ng OSE can significantly decrease the performance of syslog-ng OSE, especially if the Python code is slow. In general, the features of syslog-ng OSE are implemented in C, and are faster than implementations of the same or similar features in Python.
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Validate and lint the Python code before using it. The syslog-ng OSE application does not do any of this.
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Python error messages are available in the internal() source of syslog-ng OSE.
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You can access the name-value pairs of syslog-ng OSE directly through a message object or a dict.
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To help debugging and troubleshooting your Python code, you can send log messages to the internal() source of syslog-ng OSE. For details, see Logging from your Python code.
The following points apply to using Python blocks in syslog-ng OSE in general.
Declaration:
Python parsers consist of two parts. The first is a syslog-ng OSE parser object that you use in your syslog-ng OSE configuration, for example, in the log path. This parser references a Python class, which is the second part of the Python parsers. The Python class processes the log messages it receives, and can do virtually anything that you can code in Python.
parser <name_of_the_python_parser>{
python(
class("<name_of_the_python_class_executed_by_the_parser>")
);
};
python {
class MyParser(object):
def init(self, options):
'''Optional. This method is executed when syslog-ng is started or reloaded.'''
return True
def deinit(self):
'''Optional. This method is executed when syslog-ng is stopped or reloaded.'''
pass
def parse(self, msg):
'''Required. This method receives and processes the log message.'''
return True
};Methods of the python() parser
The init (self, options) method (optional)
The syslog-ng OSE application initializes Python objects only when it is started or reloaded. That means it keeps the state of internal variables while syslog-ng OSE is running. The init method is executed as part of the initialization. You can perform any initialization steps that are necessary for your parser to work. For example, if you want to perform a lookup from a file or a database, you can open the file or connect to the database here, or you can initialize a counter that you will increase in the parse() method.
The return value of the init() method must be True. If it returns False, or raises an exception, syslog-ng OSE will not start.
options: This optional argument contains the contents of the options() parameter of the parser object as a Python dict.
parser my_python_parser{
python(
class("MyParser")
options("regex", "seq: (?P<seq>\\d+), thread: (?P<thread>\\d+), runid: (?P<runid>\\d+), stamp: (?P<stamp>[^ ]+) (?P<padding>.*$)")
);
};
class MyParser(object):
def init(self, options):
pattern = options["regex"]
self.regex = re.compile(pattern)
self.counter = 0
return TrueThe parse(self, log_message) method
The parse() method processes the log messages it receives, and can do virtually anything that you can code in Python. This method is required, otherwise syslog-ng OSE will not start.
The return value of the parse() method must be True. If it returns False, or raises an exception, syslog-ng OSE will drop the message.
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To reference a name-value pair or a macro in the Python code, use the following format. For example, if the first argument in the definition of the function is called log-message, the value of the HOST macro is log-message['HOST'], and so on. (The log-message contains the entire log message (not just the text body) in a structure similar to a Python dict, but it is actually an object.)
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You can define new name-value pairs in the Python function. For example, if the first argument in the definition of the function is called log-message, you can create a new name-value pair like this: log_message["new-macro-name"]="value". This is useful when you parse a part of the message from Python, or lookup a value based on data extracted from the log message.
Note that the names of the name-value pairs are case-sensitive. If you create a new name-value pair called new-macro-name in Python, and want to reference it in another part of the syslog-ng OSE configuration file (for example, in a template), use the ${new-macro-name} macro.
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You cannot override hard macros (see Hard vs. soft macros).
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To list all available keys (names of name-value pairs), use the log_message.keys() function.
The deinit(self) method (optional)
This method is executed when syslog-ng OSE is stopped or reloaded.
Example: Parse loggen logs
The following sample code parses the messages of the loggen tool (for details, see The loggen manual page). The following is a sample loggen message:
<38>2017-04-05T12:16:46 localhost prg00000[1234]: seq: 0000000000, thread: 0000, runid: 1491387406, stamp: 2017-04-05T12:16:46 PADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADDPADD
The syslog-ng OSE parser object references the LoggenParser class and passes a set of regular expressions to parse the loggen messages. The init() method of the LoggenParser class compiles these expressions into a pattern. The parse method uses these patterns to extract the fields of the message into name-value pairs. The destination template of the syslog-ng OSE log statement uses the extracted fields to format the output message.
@version: 3.22
@include "scl.conf"
parser my_python_parser{
python(
class("LoggenParser")
options("regex", "seq: (?P<seq>\\d+), thread: (?P<thread>\\d+), runid: (?P<runid>\\d+), stamp: (?P<stamp>[^ ]+) (?P<padding>.*$)")
);
};
log {
source { tcp(port(5555)); };
parser(my_python_parser);
destination {
file("/tmp/regexparser.log.txt" template("seq: $seq thread: $thread runid: $runid stamp: $stamp my_counter: $MY_COUNTER"));
};
};
python {
import re
class LoggenParser(object):
def init(self, options):
pattern = options["regex"]
self.regex = re.compile(pattern)
self.counter = 0
return True
def deinit(self):
pass
def parse(self, log_message):
match = self.regex.match(log_message['MESSAGE'])
if match:
for key, value in match.groupdict().items():
log_message[key] = value
log_message['MY_COUNTER'] = self.counter
self.counter += 1
return True
return False
};Example: Parse Windows eventlogs in Python - performance
The following example uses regular expressions to process Windows log messages received in XML format from the syslog-ng Agent for Windows application. The parser extracts different fields from messages received from the Security and the Application eventlog containers. Using the following configuration file, syslog-ng OSE could process about 25000 real-life Windows log messages per second.
@version: 3.22
options {
keep-hostname(yes);
keep-timestamp(no);
stats-level(2);
use-dns(no);
};
source s_network_aa5fdf25c39d4017a8e504cdb641b477 {
network(
flags(no-parse)
ip(0.0.0.0)
log-fetch-limit(1000)
log-iw-size(100000)
max-connections(100)
port(514)
);
};
parser p_python_parser_79c31da44bb64de6b5de84be4ae15a15 {
python(options("regex_for_security", ".* Security ID: (?P<security_id>\\S+) Account Name: (?P<account_name>\\S+) Account Domain: (?P<account_domain>\\S+) Logon ID: (?P<logon_id>\\S+).*Process Name: (?P<process_name>\\S+).*EventID (?P<event_id>\\d+)", "regex_others", "(.*)EventID (?P<event_id>\\d+)")
class("EventlogParser"));
};
destination d_file_78363e1dd90c4ebcbb0ee1eff5a2e310 {
file(
"/var/testdb_working_dir/fcd713a2-d48e-4025-9192-ec4a9852cafa.$HOST"
flush-lines(1000)
log-fifo-size(200000)
);
};
log {
source(s_network_aa5fdf25c39d4017a8e504cdb641b477);
parser(p_python_parser_79c31da44bb64de6b5de84be4ae15a15);
destination(d_file_78363e1dd90c4ebcbb0ee1eff5a2e310);
flags(flow-control);
};
python {
import re
class EventlogParser(object):
def init(self, options):
self.regex_security = re.compile(options["regex_for_security"])
self.regex_others = re.compile(options["regex_others"])
return True
def deinit(self):
pass
def parse(self, log_message):
security_match = self.regex_security.match(log_message['MESSAGE'])
if security_match:
for key, value in security_match.groupdict().items():
log_message[key] = value
else:
others_match = self.regex_others.match(log_message['MESSAGE'])
if others_match:
for key, value in others_match.groupdict().items():
log_message[key] = value
return True
};Apache access log parser
The Apache access log parser can parse the access log messages of the Apache HTTP Server. The syslog-ng OSE application can separate these log messages to name-value pairs. For details on using value-pairs in syslog-ng OSE see Structuring macros, metadata, and other value-pairs. The apache-accesslog-parser() supports both the Common Log Format and the Combined Log Format of Apache (for details, see the Apache HTTP Server documentation). The following is a sample log message:
127.0.0.1 - frank [10/Oct/2000:13:55:36 -0700] "GET /apache_pb.gif HTTP/1.0" 200 2326
Starting with version
foo.com:443 1.2.3.4 - - [15/Apr/2019:14:30:16 -0400] "GET /bar.html HTTP/2.0" 500 - "https://foo.com/referer.html" "Mozilla/5.0 ..."
The syslog-ng OSE application extracts every field into name-value pairs, and adds the .apache. prefix to the name of the field.
Declaration:
parser parser_name {
apache-accesslog-parser(
prefix()
);
};The parser extracts the following fields from the messages: vhost, port, clientip, ident, auth, timestamp, rawrequest, response, bytes, referrer, and agent. The rawrequest field is further segmented into the verb, request, and httpversion fields. The syslog-ng OSE apache-accesslog-parser() parser uses the same naming convention as Logstash.
Example: Using the apache-accesslog-parser parser
In the following example, the source is a log file created by an Apache web server. The parser automatically inserts ".apache." prefix before all extracted name-value pairs. The destination is a file, that uses the format-json template function. Every name-value pair that begins with a dot (".") character will be written to the file (dot-nv-pairs). The log statement connects the source, the destination, and the parser.
source s_apache {
file(/var/log/access_log);
};
destination d_json {
file(
"/tmp/test.json"
template("$(format-json .apache.*)\n")
);
};
log {
source(s_apache);
parser { apache-accesslog-parser();};
destination(d_json);
};To use this parser, the scl.conf file must be included in your syslog-ng OSE configuration:
@include "scl.conf"
The apache-accesslog-parser() is actually a reusable configuration snippet configured parse Apache access log messages. For details on using or writing such configuration snippets, see Reusing configuration blocks. You can find the source of this configuration snippet on GitHub.
Options of apache-accesslog-parser() parsers
The apache-accesslog-parser() has the following options.
prefix()
| Synopsis: | prefix() |
Description: Insert a prefix before the name part of the parsed name-value pairs to help further processing. For example:
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To insert the my-parsed-data. prefix, use the prefix(my-parsed-data.) option.
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To refer to a particular data that has a prefix, use the prefix in the name of the macro, for example, ${my-parsed-data.name}.
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If you forward the parsed messages using the IETF-syslog protocol, you can insert all the parsed data into the SDATA part of the message using the prefix(.SDATA.my-parsed-data.) option.
Names starting with a dot (for example, .example) are reserved for use by syslog-ng OSE. If you use such a macro name as the name of a parsed value, it will attempt to replace the original value of the macro (note that only soft macros can be overwritten, see Hard vs. soft macros for details). To avoid such problems, use a prefix when naming the parsed values, for example, prefix(my-parsed-data.)
By default, apache-accesslog-parser() uses the .apache. prefix. To modify it, use the following format:
parser {
apache-accesslog-parser(prefix("apache."));
};template()
| Synopsis: | template("${<macroname>}") |
Description: The macro that contains the part of the message that the parser will process. It can also be a macro created by a previous parser of the log path. By default, the parser processes the entire message (${MESSAGE}).