[exporter/file] Ability to write logs in plaintext / using a template

[aw1cks]

Component(s)

exporter/file

Is your feature request related to a problem? Please describe.

I currently have a logging stack with I am looking to integrate/replace with OpenTelemetry. At the moment, part of our pipeline writes our logs onto disk as plain files.

I would like to drop in an OpenTelemetry pipeline to replace the current log receiver, and I'd like to use the fileexporter to write OTLP logs onto disk.

However, I cannot see a way to unmarshal the OTLP logs as plaintext; the logs seem to only be written in JSON or Protobuf OTLP representation.

This problem is described in this blog post by Cloudflare where they forked the fileexporter.

Describe the solution you'd like

It would be great to be able to export plaintext log files to disk, perhaps using a template to manipulate which log fields are written.

Describe alternatives you've considered

No response

Additional context

No response

[github-actions]

Pinging code owners:

• exporter/file: @atingchen

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[pjanotti]

Pinging @atingchen as a code owner.