Events-processing output

Internal

• events-processing

Overview

The default procedure applied to event streams, in absence of any other configuration. The procedure inspects the events and sends their string representation to the configured output stream, usually stdout. The procedure can be programmatically configured with a different output stream.

The procedure can be also configured with a custom output format. One way to provide the format specification is on command-line: format specification arguments follow the "-o" marker and end either with the last argument or when a higher level argument (file, for example) is encountered.The output format also acts as a filter - if the event does not match at least one of the output format elements, it will not be displayed at all. More details on the output format are available below: "Output Format".

some-parser [output] -o <output-format> ./file.txt

cat ./file.txt | some-parser [output] -o <output-format>

If no output format is specified, the output procedure will inspect the event, and will try to use, in order, the preferred representation of the event, as returned by the event itself (if any), the raw representation of the event, as returned by event (if any) and then a simple representation consisting in the event's timestamp, if available, and then the event's toString() invocation result. If an output format is specified, the representation will contain a leading timestamp, if the event is a timed event, whether the timestamp property name is specified in the format or not. If a timestamp is specified in the format, it will be redundantly rendered.

Output Format

The output format can be used to:

• Restrict the output to specific event properties.
• Restrict the output to specific event types.

Headers

The output procedure will display a header, based on the format, before the first event that matches the format is rendered.