Target allocator example from readme fails

[pavolloffay]

Component(s)

target allocator

What happened?

https://github.com/open-telemetry/opentelemetry-operator?tab=readme-ov-file#target-allocator

kubectl apply -f - <<EOF
apiVersion: opentelemetry.io/v1alpha1
kind: OpenTelemetryCollector
metadata:
  name: collector-with-ta
spec:
  mode: statefulset
  targetAllocator:
    enabled: true
  config: |
    receivers:
      prometheus:
        config:
          scrape_configs:
          - job_name: 'otel-collector'
            scrape_interval: 10s
            static_configs:
            - targets: [ '0.0.0.0:8888' ]
            metric_relabel_configs:
            - action: labeldrop
              regex: (id|name)
            - action: labelmap
              regex: label_(.+)
              replacement: $$1

    exporters:
      debug: {}

    service:
      pipelines:
        metrics:
          receivers: [prometheus]
          processors: []
          exporters: [debug]
EOF

Kubernetes Version

minikube version: v1.30.1

Operator version

main

Collector version

0.98.0

Environment information

Environment

OS: (e.g., "Ubuntu 20.04")
Compiler(if manually compiled): (e.g., "go 14.2")

Log output

k get pods                                                                                                                                                                                                                                                                                                                                                1 ↵ ploffay@fedora
NAME                                                 READY   STATUS             RESTARTS      AGE
collector-with-ta-collector-0                        0/1     CrashLoopBackOff   4 (8s ago)    104s
collector-with-ta-targetallocator-5bcd4d4fb5-cwq2t   0/1     CrashLoopBackOff   4 (17s ago)   104s

k logs collector-with-ta-targetallocator-5bcd4d4fb5-cwq2t ploffay@fedora
Failed to load config: error unmarshaling YAML: "69141" is invalid 'replacement' for labelmap action%

### Additional context

_No response_

[pavolloffay]

k get cm collector-with-ta-targetallocator -o yaml                                                                                                                                                                                                                                                                                                            ploffay@fedora
apiVersion: v1
data:
  targetallocator.yaml: |
    allocation_strategy: consistent-hashing
    collector_selector:
      matchlabels:
        app.kubernetes.io/component: opentelemetry-collector
        app.kubernetes.io/instance: default.collector-with-ta
        app.kubernetes.io/managed-by: opentelemetry-operator
        app.kubernetes.io/part-of: opentelemetry
      matchexpressions: []
    config:
      scrape_configs:
      - job_name: otel-collector
        metric_relabel_configs:
        - action: labeldrop
          regex: (id|name)
        - action: labelmap
          regex: label_(.+)
          replacement: 69141
        scrape_interval: 10s
        static_configs:
        - targets:
          - 0.0.0.0:8888
    filter_strategy: relabel-config
    prometheus_cr:
      pod_monitor_selector:
        matchlabels: {}
        matchexpressions: []
      scrape_interval: 30s
      service_monitor_selector:
        matchlabels: {}
        matchexpressions: []
kind: ConfigMap
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"opentelemetry.io/v1alpha1","kind":"OpenTelemetryCollector","metadata":{"annotations":{},"name":"collector-with-ta","namespace":"default"},"spec":{"config":"receivers:\n  prometheus:\n    config:\n      scrape_configs:\n      - job_name: 'otel-collector'\n        scrape_interval: 10s\n        static_configs:\n        - targets: [ '0.0.0.0:8888' ]\n        metric_relabel_configs:\n        - action: labeldrop\n          regex: (id|name)\n        - action: labelmap\n          regex: label_(.+)\n          replacement: 69141\n\nexporters:\n  debug: {}\n\nservice:\n  pipelines:\n    metrics:\n      receivers: [prometheus]\n      processors: []\n      exporters: [debug]\n","mode":"statefulset","targetAllocator":{"enabled":true}}}
  creationTimestamp: "2024-04-17T12:34:53Z"
  labels:
    app.kubernetes.io/component: opentelemetry-targetallocator
    app.kubernetes.io/instance: default.collector-with-ta
    app.kubernetes.io/managed-by: opentelemetry-operator
    app.kubernetes.io/name: collector-with-ta-targetallocator
    app.kubernetes.io/part-of: opentelemetry
    app.kubernetes.io/version: latest
  name: collector-with-ta-targetallocator
  namespace: default
  ownerReferences:
  - apiVersion: opentelemetry.io/v1beta1
    blockOwnerDeletion: true
    controller: true
    kind: OpenTelemetryCollector
    name: collector-with-ta
    uid: 5fd19ef0-0427-4c5f-962f-bed3ccb83d56
  resourceVersion: "1319"
  uid: b3ad2c67-4edb-4b51-b87c-410919a80d5c

[swiatekm-sumo]

This is a bug in the unescaping code. If there's no relabel_configs section, we skip processing the scrape config even though there might be a metric_relabel_configs section afterwards.