[extension/k8sobserver] Emit endpoint per Pod's container

[ChrsMark]

Description:

As described at #35491, it is useful to provide the option to the users for defining receiver_creator's templates per container.

In this regard, the current PR introduces a new type of Endpoint called PodContainer that matches the rule type pod.container. This Endpoint is emitted for each container of the Pod similarly to how the Port Endpoints are emitted per container that defines a port.

A complete example on how to use this feature to apply different parsing on each of the Pod's container is provided in the How to test this manually section.

Link to tracking Issue: Fixes #35491

Testing: TBA

Documentation: TBA

How to test this manually

1. Use the following values file to deploy the Collector's Helm chart

mode: daemonset

image:
  repository: otelcontribcol-dev
  tag: "latest"
  pullPolicy: IfNotPresent

command:
  name: otelcontribcol

clusterRole:
  create: true
  rules:
   - apiGroups:
     - ''
     resources:
     - 'pods'
     - 'nodes'
     verbs:
     - 'get'
     - 'list'
     - 'watch'
   - apiGroups: [ "" ]
     resources: [ "nodes/proxy"]
     verbs: [ "get" ]
   - apiGroups:
       - ""
     resources:
       - nodes/stats
     verbs:
       - get
   - nonResourceURLs:
       - "/metrics"
     verbs:
       - get

extraVolumeMounts:
 - name: varlogpods
   mountPath: /var/log/pods
   readOnly: true

extraVolumes:
  - name: varlogpods
    hostPath:
      path: /var/log/pods

config:
  extensions:
    k8s_observer:
      auth_type: serviceAccount
      node: ${env:K8S_NODE_NAME}
      observe_nodes: true
  exporters:
    debug:
      verbosity: basic
  receivers:
    receiver_creator/logs:
      watch_observers: [ k8s_observer ]
      receivers:
        filelog/busybox:
          rule: type == "pod.container" && pod.labels["otel.logs"] == "true" && container_name == "busybox"
          config:
            include:
              - /var/log/pods/`pod.namespace`_`pod.name`_`pod.uid`/`container_name`/*.log
            include_file_name: false
            include_file_path: true
            operators:
              - id: container-parser
                type: container
              - type: add
                field: attributes.log.template
                value: busybox
        filelog/lazybox:
          rule: type == "pod.container" && pod.labels["otel.logs"] == "true" && container_name == "lazybox"
          config:
            include:
              - /var/log/pods/`pod.namespace`_`pod.name`_`pod.uid`/`container_name`/*.log
            include_file_name: false
            include_file_path: true
            operators:
              - id: container-parser
                type: container
              - type: add
                field: attributes.log.template
                value: lazybox
  service:
    extensions: [health_check, k8s_observer]
    pipelines:
      logs:
        receivers: [receiver_creator/logs]
        processors: [batch]
        exporters: [debug]

2. Follow the logs of the Collector's Pod i.e: k logs -f daemonset-opentelemetry-collector-agent-2hrg5
3. Deploy a sample Pod which consists of 2 different containers:

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: daemonset-logs
  labels:
    app: daemonset-logs
spec:
  selector:
    matchLabels:
      app.kubernetes.io/component: migration-logger
      otel.logs: "true"
  template:
    metadata:
      labels:
        app.kubernetes.io/component: migration-logger
        otel.logs: "true"
    spec:
      tolerations:
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
      containers:
        - name: lazybox
          image: busybox
          args:
            - /bin/sh
            - -c
            - while true; do echo "otel logs at $(date +%H:%M:%S)" && sleep 0.1s; done
        - name: busybox
          image: busybox
          args:
            - /bin/sh
            - -c
            - while true; do echo "otel logs at $(date +%H:%M:%S)" && sleep 0.1s; done

Verify in the logs that only 2 filelog receivers are started, one per container:

2024-10-02T12:05:17.506Z	info	receivercreator@v0.110.0/observerhandler.go:96	starting receiver	{"kind": "receiver", "name": "receiver_creator/logs", "data_type": "logs", "name": "filelog/lazybox", "endpoint": "10.244.0.13", "endpoint_id": "k8s_observer/01543800-cfea-4c10-8220-387e60f65151/lazybox"}
2024-10-02T12:05:17.508Z	info	adapter/receiver.go:47	Starting stanza receiver	{"kind": "receiver", "name": "receiver_creator/logs", "data_type": "logs", "name": "filelog/lazybox/receiver_creator/logs{endpoint=\"10.244.0.13\"}/k8s_observer/01543800-cfea-4c10-8220-387e60f65151/lazybox"}
2024-10-02T12:05:17.508Z	info	receivercreator@v0.110.0/observerhandler.go:96	starting receiver	{"kind": "receiver", "name": "receiver_creator/logs", "data_type": "logs", "name": "filelog/busybox", "endpoint": "10.244.0.13", "endpoint_id": "k8s_observer/01543800-cfea-4c10-8220-387e60f65151/busybox"}
2024-10-02T12:05:17.510Z	info	adapter/receiver.go:47	Starting stanza receiver	{"kind": "receiver", "name": "receiver_creator/logs", "data_type": "logs", "name": "filelog/busybox/receiver_creator/logs{endpoint=\"10.244.0.13\"}/k8s_observer/01543800-cfea-4c10-8220-387e60f65151/busybox"}
2024-10-02T12:05:17.709Z	info	fileconsumer/file.go:256	Started watching file	{"kind": "receiver", "name": "receiver_creator/logs", "data_type": "logs", "name": "filelog/lazybox/receiver_creator/logs{endpoint=\"10.244.0.13\"}/k8s_observer/01543800-cfea-4c10-8220-387e60f65151/lazybox", "component": "fileconsumer", "path": "/var/log/pods/default_daemonset-logs-sz4zk_01543800-cfea-4c10-8220-387e60f65151/lazybox/0.log"}
2024-10-02T12:05:17.712Z	info	fileconsumer/file.go:256	Started watching file	{"kind": "receiver", "name": "receiver_creator/logs", "data_type": "logs", "name": "filelog/busybox/receiver_creator/logs{endpoint=\"10.244.0.13\"}/k8s_observer/01543800-cfea-4c10-8220-387e60f65151/busybox", "component": "fileconsumer", "path": "/var/log/pods/default_daemonset-logs-sz4zk_01543800-cfea-4c10-8220-387e60f65151/busybox/0.log"}

In addition verify that the proper attributes are added per container according to the 2 different filelog receiver definitions:

2024-10-02T12:23:55.117Z	info	ResourceLog #0
Resource SchemaURL: 
Resource attributes:
     -> k8s.pod.name: Str(daemonset-logs-sz4zk)
     -> k8s.container.restart_count: Str(0)
     -> k8s.pod.uid: Str(01543800-cfea-4c10-8220-387e60f65151)
     -> k8s.container.name: Str(lazybox)
     -> k8s.namespace.name: Str(default)
     -> container.id: Str(63a8e69bdc6ee95ee7918baf913a548190f32838adeb0e6189a8210e05157b40)
     -> container.image.name: Str(busybox)
ScopeLogs #0
ScopeLogs SchemaURL: 
InstrumentationScope  
LogRecord #0
ObservedTimestamp: 2024-10-02 12:23:54.896772888 +0000 UTC
Timestamp: 2024-10-02 12:23:54.750904381 +0000 UTC
SeverityText: 
SeverityNumber: Unspecified(0)
Body: Str(otel logs at 12:23:54)
Attributes:
     -> log.iostream: Str(stdout)
     -> logtag: Str(F)
     -> log: Map({"template":"lazybox"})
     -> log.file.path: Str(/var/log/pods/default_daemonset-logs-sz4zk_01543800-cfea-4c10-8220-387e60f65151/lazybox/0.log)
Trace ID: 
Span ID: 
Flags: 0
ResourceLog #1
Resource SchemaURL: 
Resource attributes:
     -> k8s.container.restart_count: Str(0)
     -> k8s.pod.uid: Str(01543800-cfea-4c10-8220-387e60f65151)
     -> k8s.container.name: Str(busybox)
     -> k8s.namespace.name: Str(default)
     -> k8s.pod.name: Str(daemonset-logs-sz4zk)
     -> container.id: Str(47163758424f2bc5382b1e9702301be23cab368b590b5fbf0b30affa09b4a199)
     -> container.image.name: Str(busybox)
ScopeLogs #0
ScopeLogs SchemaURL: 
InstrumentationScope  
LogRecord #0
ObservedTimestamp: 2024-10-02 12:23:54.897788935 +0000 UTC
Timestamp: 2024-10-02 12:23:54.749885634 +0000 UTC
SeverityText: 
SeverityNumber: Unspecified(0)
Body: Str(otel logs at 12:23:54)
Attributes:
     -> log.file.path: Str(/var/log/pods/default_daemonset-logs-sz4zk_01543800-cfea-4c10-8220-387e60f65151/busybox/0.log)
     -> logtag: Str(F)
     -> log.iostream: Str(stdout)
     -> log: Map({"template":"busybox"})
Trace ID: 
Span ID: 
Flags: 0

[dmitryax]

LGTM