OTel: Amplitude exporter for collector

[khvn26]

As part of the Open Structured Event Pipeline work, we built a custom OTel Collector with a Go-based Amplitude exporter. The PoC lives in otel/ in the main Flagsmith repo (branch). It needs its own repo for proper versioning, CI/CD, and release management.

Goal

Create a standalone repo (Flagsmith/flagsmith-otel-collector or similar) that houses:

• The custom Amplitude exporter as a standalone, importable Go module
• The OCB builder manifest, including ADOT (AWS Distro for OpenTelemetry) components so customers on AWS get X-Ray, CloudWatch, etc. out of the box
• A Dockerfile for the custom collector image
• CI/CD with release-please for automated versioning + releases

The exporter module must be independently importable so that users can add it to their own Collector distributions via OCB:

exporters:
  # Add to any OCB manifest
  - gomod: github.com/Flagsmith/flagsmith-otel-collector/exporter/amplitudeexporter v0.1.0

Repo structure

flagsmith-otel-collector/
  exporter/amplitudeexporter/
    go.mod              # Standalone Go module
    config.go           # api_key, endpoint, user_id_attribute, user_id_prefix, events (allowlist)
    factory.go          # NewFactory(), standard OTel Collector exporter interface
    exporter.go         # consumeLogs() → mapLogs() → POST to Amplitude HTTP V2 API
    exporter_test.go    # Unit tests
  builder-config.yaml   # OCB manifest: ADOT + contrib + Amplitude exporter
  Dockerfile            # Multi-stage: Go 1.25 → distroless runtime
  README.md

Amplitude exporter features

• Maps OTel LogRecords to Amplitude HTTP V2 API events
• Configurable user_id_attribute + user_id_prefix for identity mapping
• Reads amplitude.device_id and amplitude.session_id from log attributes for session stitching
• Glob-based events allowlist for filtering (empty = export all)
• Retry, timeout, and backoff via OTel Collector helpers
• Validated e2e against real Amplitude (events visible in dashboard)

Repo setup

• Create repo (e.g. Flagsmith/flagsmith-otel-collector)
• Move otel/ contents from the main repo
• Set up Go module path (github.com/Flagsmith/flagsmith-otel-collector)
• Ensure the exporter's go.mod is independently importable
• Update OCB manifest to include ADOT components (X-Ray exporter, CloudWatch exporter, ECS resource detector, etc.) alongside contrib and our Amplitude exporter
• Add .goreleaser.yml or equivalent for cross-platform binary builds
• Add release-please configuration for automated versioning (conventional commits)

CI/CD

• GitHub Actions workflow: lint (golangci-lint) + test (go test) on PRs
• Release workflow triggered by release-please:
  • Build binaries for linux/amd64, linux/arm64, darwin/amd64, darwin/arm64
  • Build and push Docker image (ghcr.io/flagsmith/flagsmith-otel-collector)
• Dependabot or renovate for OTel dependency updates (important — OTel releases frequently)

Hardening (can be follow-up issues)

• Batch size limits (Amplitude max 2000 events per request)
• insert_id deduplication (currently TraceID+SpanID, needs UUID fallback for log-only records)
• EU endpoint support (https://api.eu.amplitude.com/2/httpapi)
• Integration test against Amplitude's API (with a test project key in CI secrets)
• README with configuration reference, self-hosted deployment guide, and instructions for adding the exporter to custom Collector distributions