Do we support encoder/layout ?

[Alceatraz]

Hello, And:

As a skywalking demo, Dose loki4j support encoder/layout?

 <appender name="appender_sky" class="ch.qos.logback.core.ConsoleAppender">
    <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
      <layout class="org.apache.skywalking.apm.toolkit.log.logback.v1.x.TraceIdPatternLogbackLayout">
        <pattern>%level [%tid][%thread/%logger{0}]%m%n</pattern>
      </layout>
    </encoder>
  </appender>

[nehaev]

Hi @Alceatraz,

No it's not supported, but maybe you can MDC instead.

[nehaev]

Hi @slauth, the things have changed since then. Starting from Loki4j v1.5.0 there is a custom layout support for messages. See docs for more details.

[slauth]

Thanks for the quick response. I did see this in the docs. However for me it would be important to use the exact same encoder that is being used in production…

[slauth]

Maybe to explain my use case a bit more:

In production my application logs to stdout using the before mentioned LoggingEventCompositeJsonEncoder (logs are then automatically ingested to Loki by some infrastructure components). Now when developing locally, I'm currently using a FileAppender that uses the exact same encoder. Then, I use promtail to read this file and ingest to a Loki instance running locally (via Docker Compose). Would be nice if I wouldn't need the detour via file writing and reading but could directly push to Loki…

[nehaev]

You don't need the encoder. Instead, you can customize a message layout as it's outlined in the docs I've referred to. LoggingEventCompositeJsonLayout is identical to LoggingEventCompositeJsonEncoder in terms of configuration. I mean, no guarantees, but theoretically this should work.

It should look something like this:

<appender name="LOKI" class="com.github.loki4j.logback.Loki4jAppender">
    <format>
        ...
        <message class="net.logstash.logback.layout.LoggingEventCompositeJsonLayout">
            <!-- your logstash configuration goes here -->
        </message>
    </format>
    ...
</appender>

[slauth]

Ah okay so instead of re-useing the entire encoder I can re-use the same layout. Thanks!

I guess what confused me a bit here is the different namings (an XML element named <message> which sets a Layout).

[nehaev]

Let me correct my previous answer.

Starting from Loki4j v1.5.0 there is a custom layout support for messages. See JSON layout example for more details.