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: Note that parsing will fail if the format string does not match the entire template or field. Since by default syslog-ng Premium Edition (syslog-ng PE) uses the ${MESSAGE} 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} ${MESSAGE}\n") );
};
log {
source(s_file);
parser { date-parser(format("%d/%b/%Y:%H:%M:%S %Z") template("${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 ${MSG} 0 24)") );
In syslog-ng PE version 7.0.18 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"
));
The date-parser() parser has the following options.
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));
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..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}).
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(), syslog-ng PE adds the parsed date to the S_ macros (corresponding to the sent date). If you use time-zone(recvd), syslog-ng PE adds the parsed date to the R_ macros (corresponding to the received date).
time-zone()
| 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 time-zone() 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 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()
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 versus 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."));
};
The Linux audit parser can parse the log messages of the Linux audit subsystem (auditd). The syslog-ng PE application can separate these log messages to name-value pairs. For details on using value-pairs in syslog-ng PE see Structuring macros, metadata, and other value-pairs. The linux-audit-parser() is available in version 7.0.13 and later.
The following is a sample log message of auditd:
type=SYSCALL msg=audit(1441988805.991:239): arch=c000003e syscall=59 success=yes exit=0 a0=7fe49a6d0e98 a1=7fe49a6d0e40 a2=7fe49a6d0e80 a3=2 items=2 ppid=3652 pid=3660 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=5 comm="dumpe2fs" exe="/sbin/dumpe2fs" key=(null)
type=EXECVE msg=audit(1441988805.991:239): argc=3 a0="dumpe2fs" a1="-h" a2="/dev/sda1"
type=CWD msg=audit(1441988805.991:239): cwd="/"
type=PATH msg=audit(1441988805.991:239): item=0 name="/sbin/dumpe2fs" inode=137078 dev=08:01 mode=0100755 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL
type=PATH msg=audit(1441988805.991:239): item=1 name="/lib64/ld-linux-x86-64.so.2" inode=5243184 dev=08:01 mode=0100755 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL
type=PROCTITLE msg=audit(1441988805.991:239): proctitle=64756D7065326673002D68002F6465762F73646131
Certain fields of the audit log can be encoded in hexadecimal format, for example, the arch field, or the a<number> fields in the previous example. The syslog-ng PE application automatically decodes these fields (for example, the c000003e value becomes x86_64).
The syslog-ng PE application extracts every field into name-value pairs. It automatically decodes the following fields:
-
name
-
proctitle
-
path
-
dir
-
comm
-
ocomm
-
data
-
old
-
new
To parse the log messages of the Linux audit subsystem, define a parser that has the linux-audit-parser() option. By default, the parser will process the ${MESSAGE} part of the log message. To process other parts of a log message, use the template() option. You can also define the parser inline in the log path.
Declaration
parser parser_name {
linux-audit-parser(
prefix()
template()
);
};
Example: Using the linux-audit-parser() parser
In the following example, the source is a log file created by auditd. Since the audit log format is not a syslog format, the syslog parser is disabled, so that syslog-ng PE does not parse the message: flags(no-parse). The parser inserts ".auditd." prefix before all extracted name-value pairs. The destination is a file, that uses the format-json template function. Every name-value pair that begins with a dot (".") character will be written to the file (dot-nv-pairs). The log line connects the source, the destination, and the parser.
source s_auditd {
file(/var/log/audit/audit.log flags(no-parse));
};
destination d_json {
file(
"/tmp/test.json"
template("$(format-json .auditd.*)\n")
);
};
parser p_auditd {
linux-audit-parser (prefix(".auditd."));
};
log {
source(s_auditd);
parser(p_auditd);
destination(d_json);
};
You can also define the parser inline in the log path.
source s_auditd {
file(/var/log/audit/audit.log);
};
destination d_json {
file(
"/tmp/test.json"
template("$(format-json .auditd.*)\n")
);
};
log {
source(s_auditd);
parser {
linux-audit-parser (prefix(".auditd."));
};
destination(d_json);
};
