Cannot properly configure exporter args map with environment variable

[npepinpe]

Describe the bug

There's an issue when instantiating an exporter configuration bean and expecting it to be resolved using environment variables.

Spring, when given the environment variable ZEEBE_BROKER_EXPORTERS_ELASTICSEARCH_ARGS_INDEX_IGNOREVARIABLESABOVE, will create an args map with the following keys:

{
  "index": {
    "ignorevariablesabove": ...,
  }
}

However, when we use Gson to instantiate the bean, it fails, since the property is called ignoreVariablesAbove, and Gson will map it with case sensitivity.

This is unexpected from a user point of view, as for all other normal settings the above work in a case insensitive manner.

The workaround at the moment is to set it as a system property via JAVA_OPTS, to export JAVA_OPTS="${JAVA_OPTS} -Dzeebe.broker.exporters.elasticsearch.args.index.ignoreVariablesAbove=...", which preserves the camel case.

To Reproduce

Try to configure the ignoreVariablesAbove property of the ElasticsearchExporterConfiguration using ZEEBE_BROKER_EXPORTERS_ELASTICSEARCH_ARGS_INDEX_IGNOREVARIABLESABOVE, and it will fail.

Expected behavior

Exporter configuration bean instantiation works the same as the rest of Zeebe's configuration.

Log/Stacktrace

Not applicable

Environment:

• OS: Linux
• Zeebe Version: 0.24.0-SNAPSHOT
• Configuration: Elasticsearch exporter configured with minimal properties (e.g. className).

[npepinpe]

The real solution would be to get access to the application context of the spring application from the broker. From there we can instantiate any bean as per Spring rules, which aligns with how the rest of the config is deserialized.

[npepinpe]

Superseded by #7628