JSON Formatted Access Logs

In  undertow logging

Overview

Currently access logs can only be written as plain text. This plain text will be written to either a specific file or logged via the normal logging facilities. It’s desirable for a log aggregator to accept formatted log messages. Using JSON seems to be the most common format.

Issue Metadata

Issue

Dev Contacts

QE Contacts

Affected Projects or Components

  • WildFly

    • Undertow subsystem

Other Interested Projects

  • OpenShift

Requirements

Hard Requirements

  • The output must be well formed JSON.

  • The formatted message must be on a single line.

  • The output must be able to write to standard out. This is required for OpenShift.

  • A label of some sort, whether it’s hard-coded or user defined, must be added to the output. This allows filtering log messages of different types.

Nice-to-Have Requirements

  • Allow the user to choose which attributes are added to the JSON.

  • The ability to add custom key/value (meta-data) pairs to the output.

    • This would be something like { "@version" : "1" }

Non-Requirements

  • Messages will only be written to stdout at this point.

  • Messages cannot go through a log manager. The message itself needs to be structured which would not be the case if going through a log manager.

  • Messages written to the console for domain servers will not remove the [server-name] prefix from standard out.

Implementation Plan

The implementation will be done in WildFly and we should not need to do anything to Undertow itself.

A new setting resource will be introduced. The resource will be /subsystem=undertow/server=default-server/host=default-host/setting=console-access-log. This allows no changes to the current access logging and allows the console access logging to be used independently from the file or standard logging access logging.

Test Plan

Standard unit and integration tests will be used.