[Synthtrace][Inventory] K8s entities support (#197077)

Part of #196155

New Synthtrace scenario created:
[k8s_entities.ts](https://github.com/elastic/kibana/pull/197077/files#diff-33a935a5fb8848d743e40d89b018ed8ac82ae992c0778cd6cea072d091aa0647)

```
node scripts/synthtrace k8s_entities.ts --clean --live
```

Cluster sample data:
```
 {
        "_index": ".entities.v1.latest.builtin_kubernetes_cluster_ecss_from_ecs_data",
        "_id": "2060900000000000",
        "_score": 1,
        "_source": {
          "entity": {
            "type": "kubernetes_cluster_ecs",
            "id": "2060900000000000",
            "definitionId": "builtin_kubernetes_cluster_ecs",
            "displayName": "cluster_foo",
            "lastSeenTimestamp": "2024-10-21T16:15:17.570Z"
          },
          "orchestrator": {
            "cluster": {
              "name": "cluster_foo"
            }
          },
          "event": {
            "ingested": "2024-10-21T16:15:17.570Z"
          }
        }
      },
      {
        "_index": ".entities.v1.latest.builtin_kubernetes_cluster_semconvs_from_ecs_data",
        "_id": "2060900000000000",
        "_score": 1,
        "_source": {
          "entity": {
            "type": "kubernetes_cluster_semconv",
            "id": "2060900000000000",
            "definitionId": "builtin_kubernetes_cluster_semconv",
            "displayName": "cluster_foo",
            "lastSeenTimestamp": "2024-10-21T16:15:17.570Z"
          },
          "k8s": {
            "cluster": {
              "uid": "cluster_foo"
            }
          },
          "event": {
            "ingested": "2024-10-21T16:15:17.570Z"
          }
        }
      },
```

(cherry picked from commit 5e40320)

packages/kbn-apm-synthtrace-client/src/lib/entities/index.ts

@@ -11,8 +11,19 @@ import { Fields } from '../entity';
 import { serviceEntity } from './service_entity';
 import { hostEntity } from './host_entity';
 import { containerEntity } from './container_entity';
+import { k8sClusterJobEntity } from './kubernetes/cluster_entity';
+import { k8sCronJobEntity } from './kubernetes/cron_job_entity';
+import { k8sDaemonSetEntity } from './kubernetes/daemon_set_entity';
+import { k8sDeploymentEntity } from './kubernetes/deployment_entity';
+import { k8sJobSetEntity } from './kubernetes/job_set_entity';
+import { k8sNodeEntity } from './kubernetes/node_entity';
+import { k8sPodEntity } from './kubernetes/pod_entity';
+import { k8sReplicaSetEntity } from './kubernetes/replica_set';
+import { k8sStatefulSetEntity } from './kubernetes/stateful_set';
+import { k8sContainerEntity } from './kubernetes/container_entity';
 
 export type EntityDataStreamType = 'metrics' | 'logs' | 'traces';
+export type Schema = 'ecs' | 'semconv';
 
 export type EntityFields = Fields &
   Partial<{
@@ -32,4 +43,20 @@ export type EntityFields = Fields &
     [key: string]: any;
   }>;
 
-export const entities = { serviceEntity, hostEntity, containerEntity };
+export const entities = {
+  serviceEntity,
+  hostEntity,
+  containerEntity,
+  k8s: {
+    k8sClusterJobEntity,
+    k8sCronJobEntity,
+    k8sDaemonSetEntity,
+    k8sDeploymentEntity,
+    k8sJobSetEntity,
+    k8sNodeEntity,
+    k8sPodEntity,
+    k8sReplicaSetEntity,
+    k8sStatefulSetEntity,
+    k8sContainerEntity,
+  },
+};

packages/kbn-apm-synthtrace-client/src/lib/entities/kubernetes/cluster_entity.ts

@@ -0,0 +1,39 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { Schema } from '..';
+import { K8sEntity } from '.';
+
+export function k8sClusterJobEntity({
+  schema,
+  name,
+  entityId,
+  ...others
+}: {
+  schema: Schema;
+  name: string;
+  entityId: string;
+  [key: string]: any;
+}) {
+  if (schema === 'ecs') {
+    return new K8sEntity(schema, {
+      'entity.type': 'cluster',
+      'orchestrator.cluster.name': name,
+      'entity.id': entityId,
+      ...others,
+    });
+  }
+
+  return new K8sEntity(schema, {
+    'entity.type': 'cluster',
+    'k8s.cluster.uid': name,
+    'entity.id': entityId,
+    ...others,
+  });
+}

packages/kbn-apm-synthtrace-client/src/lib/entities/kubernetes/container_entity.ts

@@ -0,0 +1,39 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { Schema } from '..';
+import { K8sEntity } from '.';
+
+export function k8sContainerEntity({
+  schema,
+  id,
+  entityId,
+  ...others
+}: {
+  schema: Schema;
+  id: string;
+  entityId: string;
+  [key: string]: any;
+}) {
+  if (schema === 'ecs') {
+    return new K8sEntity(schema, {
+      'entity.type': 'container',
+      'kubernetes.container.id': id,
+      'entity.id': entityId,
+      ...others,
+    });
+  }
+
+  return new K8sEntity(schema, {
+    'entity.type': 'container',
+    'container.id': id,
+    'entity.id': entityId,
+    ...others,
+  });
+}

packages/kbn-apm-synthtrace-client/src/lib/entities/kubernetes/cron_job_entity.ts

@@ -0,0 +1,47 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { Schema } from '..';
+import { K8sEntity } from '.';
+
+export function k8sCronJobEntity({
+  schema,
+  name,
+  uid,
+  clusterName,
+  entityId,
+  ...others
+}: {
+  schema: Schema;
+  name: string;
+  uid?: string;
+  clusterName?: string;
+  entityId: string;
+  [key: string]: any;
+}) {
+  if (schema === 'ecs') {
+    return new K8sEntity(schema, {
+      'entity.type': 'cron_job',
+      'kubernetes.cronjob.name': name,
+      'kubernetes.cronjob.uid': uid,
+      'kubernetes.namespace': clusterName,
+      'entity.id': entityId,
+      ...others,
+    });
+  }
+
+  return new K8sEntity(schema, {
+    'entity.type': 'cron_job',
+    'k8s.cronjob.name': name,
+    'k8s.cronjob.uid': uid,
+    'k8s.cluster.name': clusterName,
+    'entity.id': entityId,
+    ...others,
+  });
+}

packages/kbn-apm-synthtrace-client/src/lib/entities/kubernetes/daemon_set_entity.ts

@@ -0,0 +1,47 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { Schema } from '..';
+import { K8sEntity } from '.';
+
+export function k8sDaemonSetEntity({
+  schema,
+  name,
+  uid,
+  clusterName,
+  entityId,
+  ...others
+}: {
+  schema: Schema;
+  name: string;
+  uid?: string;
+  clusterName?: string;
+  entityId: string;
+  [key: string]: any;
+}) {
+  if (schema === 'ecs') {
+    return new K8sEntity(schema, {
+      'entity.type': 'daemon_set',
+      'kubernetes.daemonset.name': name,
+      'kubernetes.daemonset.uid': uid,
+      'kubernetes.namespace': clusterName,
+      'entity.id': entityId,
+      ...others,
+    });
+  }
+
+  return new K8sEntity(schema, {
+    'entity.type': 'daemon_set',
+    'k8s.daemonset.name': name,
+    'k8s.daemonset.uid': uid,
+    'k8s.cluster.name': clusterName,
+    'entity.id': entityId,
+    ...others,
+  });
+}

packages/kbn-apm-synthtrace-client/src/lib/entities/kubernetes/deployment_entity.ts

@@ -0,0 +1,47 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { Schema } from '..';
+import { K8sEntity } from '.';
+
+export function k8sDeploymentEntity({
+  schema,
+  name,
+  uid,
+  clusterName,
+  entityId,
+  ...others
+}: {
+  schema: Schema;
+  name: string;
+  uid?: string;
+  clusterName?: string;
+  entityId: string;
+  [key: string]: any;
+}) {
+  if (schema === 'ecs') {
+    return new K8sEntity(schema, {
+      'entity.type': 'deployment',
+      'kubernetes.deployment.name': name,
+      'kubernetes.deployment.uid': uid,
+      'kubernetes.namespace': clusterName,
+      'entity.id': entityId,
+      ...others,
+    });
+  }
+
+  return new K8sEntity(schema, {
+    'entity.type': 'deployment',
+    'k8s.deployment.name': name,
+    'k8s.deployment.uid': uid,
+    'k8s.cluster.name': clusterName,
+    'entity.id': entityId,
+    ...others,
+  });
+}

packages/kbn-apm-synthtrace-client/src/lib/entities/kubernetes/index.ts

@@ -0,0 +1,76 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import type { EntityFields, Schema } from '..';
+import { Serializable } from '../../serializable';
+
+const identityFieldsMap: Record<Schema, Record<string, string[]>> = {
+  ecs: {
+    pod: ['kubernetes.pod.name'],
+    cluster: ['orchestrator.cluster.name'],
+    cron_job: ['kubernetes.cronjob.name'],
+    daemon_set: ['kubernetes.daemonset.name'],
+    deployment: ['kubernetes.deployment.name'],
+    job: ['kubernetes.job.name'],
+    node: ['kubernetes.node.name'],
+    replica_set: ['kubernetes.replicaset.name'],
+    stateful_set: ['kubernetes.statefulset.name'],
+    container: ['kubernetes.container.id'],
+  },
+  semconv: {
+    pod: ['k8s.pod.name'],
+    cluster: ['k8s.cluster.uid'],
+    cron_job: ['k8s.cronjob.name'],
+    daemon_set: ['k8s.daemonset.name'],
+    deployment: ['k8s.deployment.name'],
+    job: ['k8s.job.name'],
+    node: ['k8s.node.uid'],
+    replica_set: ['k8s.replicaset.name'],
+    stateful_set: ['k8s.statefulset.name'],
+    container: ['container.id'],
+  },
+};
+
+export class K8sEntity extends Serializable<EntityFields> {
+  constructor(schema: Schema, fields: EntityFields) {
+    const entityType = fields['entity.type'];
+    if (entityType === undefined) {
+      throw new Error(`Entity type not defined: ${entityType}`);
+    }
+
+    const entityTypeWithSchema = `kubernetes_${entityType}_${schema}`;
+    const identityFields = identityFieldsMap[schema][entityType];
+    if (identityFields === undefined || identityFields.length === 0) {
+      throw new Error(
+        `Identity fields not defined for schema: ${schema} and entity type: ${entityType}`
+      );
+    }
+
+    super({
+      ...fields,
+      'entity.type': entityTypeWithSchema,
+      'entity.definitionId': `builtin_${entityTypeWithSchema}`,
+      'entity.identityFields': identityFields,
+      'entity.displayName': getDisplayName({ identityFields, fields }),
+    });
+  }
+}
+
+function getDisplayName({
+  identityFields,
+  fields,
+}: {
+  identityFields: string[];
+  fields: EntityFields;
+}) {
+  return identityFields
+    .map((field) => fields[field])
+    .filter((_) => _)
+    .join(':');
+}

packages/kbn-apm-synthtrace-client/src/lib/entities/kubernetes/job_set_entity.ts

@@ -0,0 +1,47 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import { Schema } from '..';
+import { K8sEntity } from '.';
+
+export function k8sJobSetEntity({
+  schema,
+  name,
+  uid,
+  clusterName,
+  entityId,
+  ...others
+}: {
+  schema: Schema;
+  name: string;
+  uid?: string;
+  clusterName?: string;
+  entityId: string;
+  [key: string]: any;
+}) {
+  if (schema === 'ecs') {
+    return new K8sEntity(schema, {
+      'entity.type': 'job',
+      'kubernetes.job.name': name,
+      'kubernetes.job.uid': uid,
+      'kubernetes.namespace': clusterName,
+      'entity.id': entityId,
+      ...others,
+    });
+  }
+
+  return new K8sEntity(schema, {
+    'entity.type': 'job',
+    'k8s.job.name': name,
+    'k8s.job.uid': uid,
+    'k8s.cluster.name': clusterName,
+    'entity.id': entityId,
+    ...others,
+  });
+}