[OTLP output] Support additional endpoint path

[a-thaler]

Description The OTLP endpoint for pushing metrics can be specified in the OTLP output either with a secretRef or as plain value. There are scenarios like with Dynatrace where the endpoint gets constructed out of the dynamic environment URL plus a static path. Such setup is not supported currently.

Goal is to enhance the API so that the environment URL can be specified via a secretRef plus an additional plain text path addition.

As an example take a dynatrace config below. Here the "https://icke.com/api" part will be provided by a secretRef while "v2/otlp" is specific for otlp ingestion and needs to be added plain.

output:
        otlp:
            protocol: http
            endpoint:
                value: https://icke.com/api/v2/otlp

API Proposal:

output:
        otlp:
            protocol: http
            endpoint:
                value: https://icke.com/api
                path: /v2/otlp/v1/traces

It seems best to support a custom path for HTTP protocol only which will configure the "traces_endpoint" attribute always. By default it will take "/v1/traces".

Criteria

• As a user I can define a custom path provided in a static way (no secret ref) for my HTTP based OTLP endpoint
• The path is overriding the typical "/v1/traces" suffix, so users need to provide it as part of the custom path
• The validation will fail if the attribute is used with GRPC

Reasons

Attachments

Release Notes

Possibility to configure a custom path for an OTLP HTTP endpoint

[hisarbalik]

Additional endpoint path implemented

• The endpoint path used only with HTTP protocol
• gRPC protocol with additional endpoint path will fail via CRD validation
• Additional endpoint path will override auto-appended endpoint paths /v1/traces and /v1/metrics
• Additional path feature implemented for Metric and Trace pipelines