Metrics

Available in AxoSyslog 4.9 and later.

Updates a labeled metric counter, similarly to the metrics-probe() parser. For details, see Metrics.

You can use update_metric to count the processed messages, and create labeled metric counters based on the fields of the processed messages.

You can configure the name of the counter to update and the labels to add. The name of the counter is an unnamed, mandatory option. Note that the name is automatically prefixed with the syslogng_ string. For example:

update_metric(
    "my_counter_name",
    labels={
        "host": ${HOST},
        "app": ${PROGRAM},
        "id": ${SOURCE}
    }
);

This results in counters like:

syslogng_my_counter_name{app="example-app", host="localhost", source="s_local_1"} 3

Options

increment

An integer, or an expression that resolves to an integer that defines the increment of the counter. The following example defines a counter called syslogng_input_event_bytes_total, and increases its value with the size of the incoming message (in bytes).

update_metric(
    "input_event_bytes_total",
    labels={
        "host": ${HOST},
        "app": ${PROGRAM},
        "id": ${SOURCE}
    },
    increment=${RAWMSG_SIZE}
);

labels

The labels used to create separate counters, based on the fields of the messages processed by update_metric. Use the following format:

labels(
    {
      "name-of-label1": "value-of-the-label1",
      ... ,
      "name-of-labelx": "value-of-the-labelx"
    }
)

level

Sets the stats level of the generated metrics.

Note: Drivers configured with internal(yes) register their metrics on level 3. That way if you are creating an SCL, you can disable the built-in metrics of the driver, and create metrics manually using update_metric.