Add an example of how to configure extraOperators

[matthewmodestino]

I have an OTel native logging user that wants to set different index values for logs emitted from a single pod.

I believe setting extraOperators should allow them to set router example to match a value then route to another operator that will set the index value.

Could use an example of how to set something like that here:

splunk-otel-collector-chart/helm-charts/splunk-otel-collector/values.yaml

Lines 424 to 425 in 75cfd0b

	# https://github.com/open-telemetry/opentelemetry-log-collection/blob/main/docs/operators/README.md#what-operators-are-available
	extraOperators: []

[matthewmodestino]

After reviewing the extraOperators helm templates, we will likely need to adjust the log pipeline to insert rendered extraOperators above the multiline recombine rules, or insert custom routes to direct to the custom operators, then to the multiline operator blocks. otherwise they will not be reached by events moving through the pipeline:

splunk-otel-collector-chart/helm-charts/splunk-otel-collector/templates/config/_otel-agent.tpl

Lines 345 to 363 in 8bbb834

	{{- if .Values.logsCollection.containers.multilineConfigs }}
	- type: router
	routes:
	{{- range $.Values.logsCollection.containers.multilineConfigs }}
	- output: {{ include "splunk-otel-collector.newlineKey" . | quote }}
	expr: {{ include "splunk-otel-collector.newlineExpr" . | quote }}
	{{- end }}
	default: clean-up-log-record
	{{- range $.Values.logsCollection.containers.multilineConfigs }}
	- type: recombine
	id: {{ include "splunk-otel-collector.newlineKey" . | quote}}
	output: clean-up-log-record
	combine_field: log
	is_first_entry: '($$.log) matches {{ .firstEntryRegex | quote }}'
	{{- end }}
	{{- end }}
	{{- with .Values.logsCollection.containers.extraOperators }}
	{{ . | toYaml | nindent 6 }}
	{{- end }}

Currently in testing adding custom Operators to deal with the user need to set index on events in a single log, I am editing the configmap directly.

Will also likely need to expose options for processors as well to customize outcomes customers may need.

[matthewmodestino]

Here's an example of how I used extraOperators to slide in a custom recombine rule for docker truncated events:

    extraOperators:
      - combine_field: log
        id: docker-recombine
        is_last_entry: ($$.log) endsWith "\n"
        type: recombine
        source_identifier: $$resource["com.splunk.source"]
        combine_with: ""

[atoulme]

Would you like to push your example into the examples folder? I recently contributed this one https://github.com/signalfx/splunk-otel-collector-chart/blob/main/examples/associate-namespace-to-index.yaml