8.1.1.1. Using embedded log statements

Embedded log statements (for details, see Section 8.1.1, Embedded log statements) re-use the results of processing messages (for example the results of filtering or rewriting) to create complex log paths. Embedded log statements use the same syntax as regular log statements, but they cannot contain additional sources. To define embedded log statements, use the following syntax:

log {
    source(s1); source(s2); ...

    optional_element(filter1|parser1|rewrite1);
    optional_element(filter2|parser2|rewrite2);
    ...
    destination(d1); destination(d2); ...

    #embedded log statement
    log {
        optional_element(filter1|parser1|rewrite1);
        optional_element(filter2|parser2|rewrite2);
        ...
        destination(d1); destination(d2); ...

        #another embedded log statement
        log {
            optional_element(filter1|parser1|rewrite1);
            optional_element(filter2|parser2|rewrite2);
            ...
            destination(d1); destination(d2); ...
        };
    };
    #set flags after the embedded log statements
    flags(flag1[, flag2...]);
};
Example 8.2. Using embedded log paths

The following log path sends every message to the configured destinations: both the d_file1 and the d_file2 destinations receive every message of the source.

log { source(s_localhost); destination(d_file1); destination(d_file2); };

The next example is equivalent with the one above, but uses an embedded log statement.

log { source(s_localhost); destination(d_file1);
    log { destination(d_file2); };
};

The following example uses two filters:

  • messages coming from the host 192.168.1.1 are sent to the d_file1 destination, and

  • messages coming from the host 192.168.1.1 and containing the string example are sent to the d_file2 destination.

log { source(s_localhost); filter { host(192.168.1.1); }; destination(d_file1);
    log { message("example"); destination(d_file2); };
};

The following example collects logs from multiple source groups and uses the source() filter in the embedded log statement to select messages of the s_network source group.

log { source(s_localhost); source(s_network); destination(d_file1);
    log {  filter { source(s_network); }; destination(d_file2); };
};