Solace Appender for log4j2

This is a Solace PubSub+ Appender for log4j2. It can use either Direct messaging, or Guaranteed (but does not attempt redelivery if a NACK is received). The published topic is completely dynamic! E.g.:

log4j-log/AaronsThinkPad3-12540/INFO/pub-thread/com/solacesystems/jcsmp/protocol/impl/TcpClientChannel
                     |      |    |      |         |-->
                 hostname-PID/level/thread-name/class......
                 (or app name)

So much better than crappy JMS and Kafka publishers that just publish to a fixed static topic, like "logs" or "systemXYZ.logs"! Same with most of the MQTT ones I've found online. The topic structure is currently hard-coded, but perhaps a future version will allow it to be specified, similar to the PatternLayout.

This multi-level topic structure allows you to do things like:

• Subscribe to all WARNs: log4j*/*/WARN/>
• Subscribe to logs from Aaron's machines: log4j*/Aaron*/>
• Subscribe to any log from the main thread: log4j*/*/*/main/>
• Subscribe to any exception: log4j-exc/>

I should make a better MQTT version as well, since MQTT also supports awesome dynamic hierarchical topics. Although MQTT doesn't support prefix-wildcards.

Options

As an example, in your log4j2.xml file, specify a Solace Appender, something like:

...
  <Appenders>
    <Solace name="solaceLogger" host="tcp://192.168.42.35" vpn="logs" username="test" password="secret" appName="${sys:appName:DefaultAppName}">
      <PatternLayout>
        <Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
      </PatternLayout>
    </Solace>
  </Appenders>
  <Loggers>
    <Root level="info">
      <AppenderRef ref="solaceLogger"/>
    </Root>
  </Loggers>
...

• host: hostname or IP address of the Solace broker (default="tcp://localhost:55555")
• vpn: Message VPN to connect to (default="default")
• username: Client username to connect with (default="default")
• password: Password for client connection, if required (default="")
• direct: ["true"|"false"] Whether to use Direct or Guaranteed messages (default="false")
• appName: Custom string to use instead of "hostname+pid" in topic

Shadow MegaJAR bundle

Has JCSMP 10.22.0 bundled inside, makes importing the Appender into other Solace projects easier. Using 10.22 as there's a bug in the current JCSMP version that breaks something during log4j's static initialization.