Parsing dates and timestamps

The date parser can extract dates from non-syslog messages. It operates by default on the ${MESSAGE} 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 time-stamp(recvd) option.)

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, AxoSyslog 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, AxoSyslog 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 AxoSyslog 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.