# OpenTelemetry Collector Configuration
# Receives metrics, logs, and traces and exports to various backends

receivers:
  # OTLP receiver (standard OpenTelemetry protocol)
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318

  # Prometheus receiver (scrape Prometheus endpoints)
  prometheus:
    config:
      scrape_configs:
        - job_name: 'otel-collector'
          scrape_interval: 30s
          static_configs:
            - targets: ['localhost:8888']

  # Host metrics (CPU, memory, disk, network)
  hostmetrics:
    collection_interval: 30s
    scrapers:
      cpu:
      memory:
      disk:
      network:
      filesystem:
      load:

  # Kubernetes receiver (cluster metrics)
  k8s_cluster:
    auth_type: serviceAccount
    node_conditions_to_report: [Ready, MemoryPressure, DiskPressure]
    distribution: kubernetes

  # Zipkin receiver (legacy tracing)
  zipkin:
    endpoint: 0.0.0.0:9411

processors:
  # Batch processor (improves performance)
  batch:
    timeout: 10s
    send_batch_size: 1024
    send_batch_max_size: 2048

  # Memory limiter (prevent OOM)
  memory_limiter:
    check_interval: 1s
    limit_mib: 512
    spike_limit_mib: 128

  # Resource processor (add resource attributes)
  resource:
    attributes:
      - key: environment
        value: production
        action: insert
      - key: cluster.name
        value: prod-cluster
        action: insert

  # Attributes processor (modify span/metric attributes)
  attributes:
    actions:
      - key: http.url
        action: delete  # Remove potentially sensitive URLs
      - key: db.statement
        action: hash    # Hash SQL queries for privacy

  # Filter processor (drop unwanted data)
  filter:
    metrics:
      # Drop metrics matching criteria
      exclude:
        match_type: regexp
        metric_names:
          - ^go_.*      # Drop Go runtime metrics
          - ^process_.* # Drop process metrics

  # Tail sampling (intelligent trace sampling)
  tail_sampling:
    decision_wait: 10s
    num_traces: 100
    policies:
      # Always sample errors
      - name: error-policy
        type: status_code
        status_code:
          status_codes: [ERROR]

      # Sample slow traces
      - name: latency-policy
        type: latency
        latency:
          threshold_ms: 1000

      # Sample 10% of others
      - name: probabilistic-policy
        type: probabilistic
        probabilistic:
          sampling_percentage: 10

  # Span processor (modify spans)
  span:
    name:
      to_attributes:
        rules:
          - ^\/api\/v1\/users\/(?P<user_id>.*)$
      from_attributes:
        - db.name
        - http.method

exporters:
  # Prometheus exporter (expose metrics endpoint)
  prometheus:
    endpoint: 0.0.0.0:8889
    namespace: otel

  # OTLP exporters (send to backends)
  otlp/tempo:
    endpoint: tempo:4317
    tls:
      insecure: true

  otlp/mimir:
    endpoint: mimir:4317
    tls:
      insecure: true

  # Loki exporter (for logs)
  loki:
    endpoint: http://loki:3100/loki/api/v1/push
    labels:
      resource:
        service.name: "service_name"
        service.namespace: "service_namespace"
      attributes:
        level: "level"

  # Jaeger exporter (alternative tracing backend)
  jaeger:
    endpoint: jaeger:14250
    tls:
      insecure: true

  # Elasticsearch exporter (for logs)
  elasticsearch:
    endpoints:
      - http://elasticsearch:9200
    logs_index: otel-logs
    traces_index: otel-traces

  # CloudWatch exporter (AWS)
  awscloudwatch:
    region: us-east-1
    namespace: MyApp
    log_group_name: /aws/otel/logs
    log_stream_name: otel-collector

  # Datadog exporter
  datadog:
    api:
      key: ${DD_API_KEY}
      site: datadoghq.com

  # File exporter (debugging)
  file:
    path: /tmp/otel-output.json

  # Logging exporter (console output for debugging)
  logging:
    verbosity: detailed
    sampling_initial: 5
    sampling_thereafter: 200

extensions:
  # Health check endpoint
  health_check:
    endpoint: 0.0.0.0:13133

  # Pprof endpoint (for profiling)
  pprof:
    endpoint: 0.0.0.0:1777

  # ZPages (internal diagnostics)
  zpages:
    endpoint: 0.0.0.0:55679

service:
  extensions: [health_check, pprof, zpages]

  pipelines:
    # Traces pipeline
    traces:
      receivers: [otlp, zipkin]
      processors: [memory_limiter, batch, tail_sampling, resource, span]
      exporters: [otlp/tempo, jaeger, logging]

    # Metrics pipeline
    metrics:
      receivers: [otlp, prometheus, hostmetrics, k8s_cluster]
      processors: [memory_limiter, batch, filter, resource]
      exporters: [otlp/mimir, prometheus, awscloudwatch]

    # Logs pipeline
    logs:
      receivers: [otlp]
      processors: [memory_limiter, batch, resource, attributes]
      exporters: [loki, elasticsearch, awscloudwatch]

  # Telemetry (collector's own metrics)
  telemetry:
    logs:
      level: info
    metrics:
      address: 0.0.0.0:8888

# Notes:
# 1. Replace ${DD_API_KEY} with actual API key or use environment variable
# 2. Adjust endpoints to match your infrastructure
# 3. Comment out exporters you don't use
# 4. Adjust sampling rates based on your volume and needs
# 5. Add TLS configuration for production deployments