[Agent] Expose stream.* data in every event (elastic#17468)

[Agent] Expose stream.* data in every event (elastic#17468)

(cherry picked from commit 70fba87)

x-pack/elastic-agent/CHANGELOG.asciidoc

@@ -25,3 +25,5 @@
 - Display the stability of the agent at enroll and start.  {pull}17336[17336]
 - Support for config constraints {pull}17112[17112]
 - Introduced post install hooks {pull}17241[17241]
+- Expose stream.* variables in events {pull}17468[17468]
+

x-pack/elastic-agent/pkg/agent/program/program_test.go

@@ -12,6 +12,7 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	yaml "gopkg.in/yaml.v2"
@@ -492,7 +493,7 @@ func TestConfiguration(t *testing.T) {
 				require.NoError(t, err)
 				var m map[string]interface{}
 				err = yamltest.FromYAML(programConfig, &m)
-				require.NoError(t, err)
+				require.NoError(t, errors.Wrap(err, program.Cmd()))
 
 				compareMap := &transpiler.MapVisitor{}
 				program.Config.Accept(compareMap)

x-pack/elastic-agent/pkg/agent/program/testdata/constraints_config-filebeat.yml

@@ -5,6 +5,12 @@ filebeat:
       - /var/log/hello1.log
       - /var/log/hello2.log
     index: logs-generic-default
+    processors:
+      - add_fields:
+          fields:
+            stream.type: logs
+            stream.dataset: generic
+            stream.namespace: default
 output:
   elasticsearch:
     hosts:

x-pack/elastic-agent/pkg/agent/program/testdata/enabled_output_true-filebeat.yml

@@ -5,6 +5,12 @@ filebeat:
       - /var/log/hello1.log
       - /var/log/hello2.log
     index: logs-generic-default
+    processors:
+      - add_fields:
+          fields:
+            stream.type: logs
+            stream.dataset: generic
+            stream.namespace: default
 output:
   elasticsearch:
     enabled: true

x-pack/elastic-agent/pkg/agent/program/testdata/enabled_true-filebeat.yml

@@ -6,6 +6,12 @@ filebeat:
       - /var/log/hello1.log
       - /var/log/hello2.log
     index: logs-generic-default
+    processors:
+      - add_fields:
+          fields:
+            stream.type: logs
+            stream.dataset: generic
+            stream.namespace: default
 output:
   elasticsearch:
     hosts:

x-pack/elastic-agent/pkg/agent/program/testdata/single_config-filebeat.yml

@@ -7,6 +7,12 @@ filebeat:
     index: logs-generic-default
     vars:
       var: value
+    processors:
+      - add_fields:
+          fields:
+            stream.type: logs
+            stream.dataset: generic
+            stream.namespace: default
 output:
   elasticsearch:
     hosts:

x-pack/elastic-agent/pkg/agent/program/testdata/single_config-metricbeat.yml

@@ -4,10 +4,25 @@ metricbeat:
     metricsets: [status]
     index: metrics-docker.status-default
     hosts: ["http://127.0.0.1:8080"]
+    processors:
+    - add_fields:
+        fields:
+          stream.type: metrics
+          stream.dataset: docker.status
+          stream.namespace: default
   - module: apache
     metricsets: [info]
     index: metrics-generic-testing
     hosts: ["http://apache.remote"]
+    processors:
+      - add_fields:
+          fields:
+            should_be: first
+      - add_fields:
+          fields:
+            stream.type: metrics
+            stream.dataset: generic
+            stream.namespace: testing
 output:
   elasticsearch:
     hosts: [127.0.0.1:9200, 127.0.0.1:9300]

x-pack/elastic-agent/pkg/agent/program/testdata/single_config.yml

@@ -38,6 +38,10 @@ datasources:
     use_output: default
     inputs:
       - type: apache/metrics
+        processors:
+          - add_fields:
+              fields:
+                should_be: first
         streams:
           - enabled: true
             metricset: info

x-pack/elastic-agent/pkg/agent/transpiler/merge_strategy.go

@@ -0,0 +1,95 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package transpiler
+
+import "fmt"
+
+type injector interface {
+	Inject(target []Node, source interface{}) []Node
+	InjectItem(target []Node, source Node) []Node
+	InjectCollection(target []Node, source []Node) []Node
+}
+
+func mergeStrategy(strategy string) injector {
+
+	switch strategy {
+	case "insert_before":
+		return injectBeforeInjector{}
+	case "insert_after":
+		return injectAfterInjector{}
+	case "replace":
+		return replaceInjector{}
+	case "noop":
+		return noopInjector{}
+	}
+
+	return injectAfterInjector{}
+}
+
+type noopInjector struct{}
+
+func (i noopInjector) Inject(target []Node, source interface{}) []Node {
+	return inject(i, target, source)
+}
+
+func (noopInjector) InjectItem(target []Node, source Node) []Node { return target }
+
+func (noopInjector) InjectCollection(target []Node, source []Node) []Node { return target }
+
+type injectAfterInjector struct{}
+
+func (i injectAfterInjector) Inject(target []Node, source interface{}) []Node {
+	return inject(i, target, source)
+}
+
+func (injectAfterInjector) InjectItem(target []Node, source Node) []Node {
+	return append(target, source)
+}
+
+func (injectAfterInjector) InjectCollection(target []Node, source []Node) []Node {
+	return append(target, source...)
+}
+
+type injectBeforeInjector struct{}
+
+func (i injectBeforeInjector) Inject(target []Node, source interface{}) []Node {
+	return inject(i, target, source)
+}
+
+func (injectBeforeInjector) InjectItem(target []Node, source Node) []Node {
+	return append([]Node{source}, target...)
+}
+
+func (injectBeforeInjector) InjectCollection(target []Node, source []Node) []Node {
+	return append(source, target...)
+}
+
+type replaceInjector struct{}
+
+func (i replaceInjector) Inject(target []Node, source interface{}) []Node {
+	return inject(i, target, source)
+}
+
+func (replaceInjector) InjectItem(target []Node, source Node) []Node {
+	return []Node{source}
+}
+
+func (replaceInjector) InjectCollection(target []Node, source []Node) []Node {
+	return source
+}
+
+func inject(i injector, target []Node, source interface{}) []Node {
+	if sourceCollection, ok := source.([]Node); ok {
+		fmt.Printf(">>[%T] list of nodes %T %d\n", i, source, len(sourceCollection))
+		return i.InjectCollection(target, sourceCollection)
+	}
+
+	if node, ok := source.(Node); ok {
+		fmt.Printf(">> one of nodes %T\n", source)
+		return i.InjectItem(target, node)
+	}
+
+	return target
+}