syslog-ng Open Source Edition 3.30 - Administration Guide

Example: Using the date-parser()

In the following example, syslog-ng OSE parses dates like 01/Jan/2016:13:05:05 PST from a field called MY_DATE using the following format string: format("%d/%b/%Y:%H:%M:%S %Z") (how you create this field from the incoming message is not shown in the example). In the destination template every message will begin with the timestamp in ISODATE format. Since the syslog parser is disabled, syslog-ng OSE will include the entire original message (including the original timestamp) in the ${MESSAGE} macro.

source s_file {
    file("/tmp/input" flags(no-parse));
};

destination d_file {
    file(
        "/tmp/output"
        template("${S_ISODATE} ${MESSAGE}\n")
    );
};

log {
    source(s_file);
    parser { date-parser(format("%d/%b/%Y:%H:%M:%S %Z") template("${MY_DATE}")); };
    destination(d_file);
};

In the template option, you can use template functions to specify which part of the message to parse with the format string. The following example selects the first 24 characters of the ${MESSAGE} macro.

date-parser(format("%d/%b/%Y:%H:%M:%S %Z") template("$(substr ${MESSAGE} 0 24)") );

In syslog-ng OSE version 3.23 and later, you can specify a comma-separated list of formats to parse multiple date formats with a single parser. For example:

date-parser(format(
    "%FT%T.%f",
    "%F %T,%f",
    "%F %T"
));

If you need to modify or correct the timezone of the message after parsing, see Rewrite the timezone of a message.

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: 3.30
@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: 3.30
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
};