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syslog-ng Premium Edition 7.0.12 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng The syslog-ng PE quick-start guide The syslog-ng PE configuration file Collecting log messages — sources and source drivers
How sources work default-network-drivers: Receive and parse common syslog messages internal: Collecting internal messages file: Collecting messages from text files wildcard-file: Collecting messages from multiple text files network: Collecting messages using the RFC3164 protocol (network() driver) osquery: Collect and parse osquery result logs pipe: Collecting messages from named pipes program: Receiving messages from external applications python: writing server-style Python sources python-fetcher: writing fetcher-style Python sources snmptrap: Read Net-SNMP traps sun-streams: Collecting messages on Sun Solaris syslog: Collecting messages using the IETF syslog protocol (syslog() driver) system: Collecting the system-specific log messages of a platform systemd-journal: Collecting messages from the systemd-journal system log storage systemd-syslog: Collecting systemd messages using a socket tcp, tcp6, udp, udp6: Collecting messages from remote hosts using the BSD syslog protocol unix-stream, unix-dgram: Collecting messages from UNIX domain sockets windowsevent: Collecting Windows event logs
Sending and storing log messages — destinations and destination drivers
elasticsearch: Sending messages directly to Elasticsearch version 1.x elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher file: Storing messages in plain-text files hdfs: Storing messages on the Hadoop Distributed File System (HDFS) http: Posting messages over HTTP kafka: Publishing messages to Apache Kafka logstore: Storing messages in encrypted files mongodb: Storing messages in a MongoDB database network: Sending messages to a remote log server using the RFC3164 protocol (network() driver) pipe: Sending messages to named pipes program: Sending messages to external applications python: writing custom Python destinations smtp: Generating SMTP messages (e-mail) from logs splunk-hec: Sending messages to Splunk HTTP Event Collector sql: Storing messages in an SQL database syslog: Sending messages to a remote logserver using the IETF-syslog protocol syslog-ng: Forwarding messages and tags to another syslog-ng node tcp, tcp6, udp, udp6: Sending messages to a remote log server using the legacy BSD-syslog protocol (tcp(), udp() drivers) unix-stream, unix-dgram: Sending messages to UNIX domain sockets usertty: Sending messages to a user terminal — usertty() destination Client-side failover
Routing messages: log paths, flags, and filters Global options of syslog-ng PE TLS-encrypted message transfer Advanced Log Transfer Protocol Reliability and minimizing the loss of log messages Manipulating messages parser: Parse and segment structured messages Processing message content with a pattern database Correlating log messages Enriching log messages with external data Monitoring statistics and metrics of syslog-ng Multithreading and scaling in syslog-ng PE Troubleshooting syslog-ng Best practices and examples The syslog-ng manual pages About us

Options of XML parsers

The XML parser has the following options.

drop-invalid
Synopsis: drop-invalid()
Format: yes|no
Default: no
Mandatory: no

Description: If set, messages with an invalid XML will be dropped entirely.

exclude-tags
Synopsis: exclude-tags()
Format: list of globs
Default:

None

If not set, no filtering is done.

Mandatory: no

Description: The XML parser matches tags against the listed globs. If there is a match, the given subtree of the XML will be omitted.

Example: Using exclude_tags
parser xml_parser {
       xml(template("$MSG") exclude_tags("tag1", "tag2", "inner*"));
};

From this XML input:

<tag1>Text1</tag1><tag2>Text2</tag2><tag3>Text3<innertag>TextInner</innertag></tag3>

The following output is generated:

{"_xml":{"tag3":"Text3"}}
prefix()
Synopsis: prefix()

Description: Insert a prefix before the name part of the parsed name-value pairs to help further processing. For example:

  • To insert the my-parsed-data. prefix, use the prefix(my-parsed-data.) option.

  • 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} .

  • 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 PE. 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.)

The prefix() option is optional and its default value is ".xml".

strip-whitespaces
Synopsis: strip-whitespaces()
Format: yes|no
Default: no
Mandatory: no

Description: Strip the whitespaces from the XML text nodes before adding them to the message.

Example: Using strip-whitespaces
parser xml_parser {
       xml(template("$MSG") strip_whitespaces(yes));
};

From this XML input:

<tag1> Tag </tag1>

The following output is generated:

{"_xml":{"tag1":"Tag"}}
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}).

Parsing dates and timestamps

The date parser can extract dates from non-syslog messages. It operates by default on the ${MSG} part of the log message, but can operate on any template or field provided. The parsed date will be available as the sender date (that is, the ${S_DATE}, ${S_ISODATE}, ${S_MONTH}, and so on, and related macros). (To store the parsed date as the received date, use the timestamp(recvd) option.)

Note that parsing will fail if the format string does not match the entire template or field. Since by default syslog-ng PE uses the ${MSG} part of the log message, parsing will fail, unless the log message contains only a date, but that is unlikely, so practically you will have to segment the message (for example, using a csv-parser()) before using the date-parser(). You can also use date-parser() to parse dates received in a JSON or key-value-formatted log message.

Declaration:
parser parser_name {
    date-parser(
        format("<format-string-for-the-date>")
        template("<field-to-parse>'")
    );
};
Example: Using the date-parser()

In the following example, syslog-ng PE 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 PE 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);
    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 ${MSG} 0 24)") );

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 PE 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..32)
%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}).

timestamp()
Synopsis: stamp | recvd
Default: stamp

Description: Determines if the parsed date values are treated as sent or received date. If you use timezone(stamp), syslog-ng PE adds the parsed date to the S_ macros (corresponding to the sent date). If you use timezone(recvd), syslog-ng PE adds the parsed date to the R_ macros (corresponding to the received date).

timezone()
Synopsis: timezone(string)
Default:

Description: If this option is set, syslog-ng PE assumes that the parsed timestamp refers to the specified timezone. The timezone set in the timezone() option overrides any timezone information parsed from the timestamp.

The timezone can be specified as using the name of the (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.

The Cisco Parser

The Cisco Parser can parse the log messages of various Cisco devices. The messages of these devices often do not completely comply with the syslog RFCs, making them difficult to parse. The cisco-parser() of syslog-ng PE solves this problem, and can separate these log messages to name-value pairs, extracting also the Cisco-specific values, for example, the mnemonic. For details on using value-pairs in syslog-ng PE see Structuring macros, metadata, and other value-pairs. The parser can parse variations of the following message format:

<pri>(sequence: )?(origin-id: )?(timestamp? timezone?: )?%msg

For example:

<189>29: foo: *Apr 29 13:58:40.411: %SYS-5-CONFIG_I: Configured from console by console
<190>30: foo: *Apr 29 13:58:46.411: %SYS-6-LOGGINGHOST_STARTSTOP: Logging to host 192.168.1.239 stopped - CLI initiated
<190>31: foo: *Apr 29 13:58:46.411: %SYS-6-LOGGINGHOST_STARTSTOP: Logging to host 192.168.1.239 started - CLI initiated
<189>32: 0.0.0.0: *Apr 29 13:59:12.491: %SYS-5-CONFIG_I: Configured from console by console

Note that not every Cisco log message conforms to this format. If you find a message that the cisco-parser() cannot properly parse, send it to documentation@balabit.com so we can improve the parser.

The syslog-ng PE application normalizes the parsed log messages into the following format:

${MESSAGE}=%FAC-SEV-MNEMONIC: message
${HOST}=origin-id

By default, the Cisco-specific fields are extracted into the following name-value pairs:${.cisco.facility}, ${.cisco.severity}, ${.cisco.mnemonic}. You can change the prefix using the prefix option.

Declaration:
@version: 7.0
@include "scl.conf"
log {
    source { udp(flags(no-parse)); };
    parser { cisco-parser(); };
    destination { ... };
};

Note that you have to disable message parsing in the source using the flags(no-parse) option for the parser to work.

The cisco-parser() is actually a reusable configuration snippet configured to parse Cisco 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.

prefix()
Synopsis: prefix()

Description: Insert a prefix before the name part of the parsed name-value pairs to help further processing. For example:

  • To insert the my-parsed-data. prefix, use the prefix(my-parsed-data.) option.

  • 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} .

  • 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 PE. 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, cisco-parser() uses the cisco. prefix. To modify it, use the following format:

parser { cisco-parser(prefix("myprefix.")); };
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