feat: switch to autoexport for OpenTelemetry span exporter

[PKeidel]

This PR is about OTEL_EXPORTER_OTLP_PROTOCOL beeing ignored by caddy otel exporter #6483.

I used the Dockerfile provided by trajano (#6483 (comment)) to build with my changes and tested them with these files:

docker-compose.yml

services:
  caddy:
    image: caddy-fix
    #image: caddy:alpine
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile
    ports:
      - "80:80"
      - "443:443"
    environment:
      OTEL_SERVICE_NAME: 'my-app'
      OTEL_EXPORTER_OTLP_PROTOCOL: 'http/protobuf'
      OTEL_EXPORTER_OTLP_ENDPOINT: 'http://otel-collector:4318'

  otel-collector:
    image: otel/opentelemetry-collector-contrib:latest
    command: [ '--config=/etc/otel-collector-config.yaml' ]
    volumes:
      - ./otel-collector-config.yaml:/etc/otel-collector-config.yaml

otel-collector-config.yml

receivers:
  # Data sources: traces, metrics, logs
  otlp:
    protocols:
      http:
        endpoint: 0.0.0.0:4318

exporters:
  debug:
    verbosity: detailed

service:
  pipelines:
    traces:
      receivers: [ otlp ]
      processors: [ ]
      exporters: [ debug ]

Caddyfile

:80 {
    tracing {
        span frankenphp
    }
    root .
}

I used these commands:

go get go.opentelemetry.io/contrib/exporters/autoexport
go mod tidy

No AI was used.

[CLAassistant]

All committers have signed the CLA.

[francislavoie]

Does this also resolve everything in #5743 ?

[trajano]

IIRC correctly it should its been a while since I created the original PR which was blocked by linting issues due to some Go lang update or something.

[mholt]

Alrighty, thanks -- let's see how this goes

[trajano]

Awesome, can't wait to drop my fork.

[PKeidel]

Hi, thank you for that really great and fast contribution experience :)

[mholt]

We're looking for more collaborators & maintainers, so feel free to keep it up! Including reviewing existing PRs or addressing issues and such. If you want 🙂