Cherry-pick #18585 to 7.x: Add support for array parsing in azure-eventhub input

CHANGELOG.next.asciidoc

@@ -410,6 +410,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Improve ECS categorization field mappings in osquery module. {issue}16176[16176] {pull}17881[17881]
 - Add support for v10, v11 and v12 logs on Postgres {issue}13810[13810] {pull}17732[17732]
 - Add dashboard for Google Cloud Audit and AWS CloudTrail. {pull}17379[17379]
+- Add support for array parsing in azure-eventhub input. {pull}18585[18585]
 - The `logstash` module can now automatically detect the log file format (JSON or plaintext) and process it accordingly. {issue}9964[9964] {pull}18095[18095]
 - Improve ECS categorization field mappings in coredns module. {issue}16159[16159] {pull}18424[18424]
 - Improve ECS categorization field mappings in envoyproxy module. {issue}16161[16161] {pull}18395[18395]

x-pack/filebeat/input/azureeventhub/input.go

@@ -203,14 +203,32 @@ func (a *azureInput) processEvents(event *eventhub.Event, partitionID string) bo
 
 // parseMultipleMessages will try to split the message into multiple ones based on the group field provided by the configuration
 func (a *azureInput) parseMultipleMessages(bMessage []byte) []string {
-	var obj map[string][]interface{}
-	err := json.Unmarshal(bMessage, &obj)
-	if err != nil {
-		a.log.Errorw(fmt.Sprintf("deserializing multiple messages using the group object `records`"), "error", err)
-	}
+	var mapObject map[string][]interface{}
 	var messages []string
-	if len(obj[expandEventListFromField]) > 0 {
-		for _, ms := range obj[expandEventListFromField] {
+	// check if the message is a "records" object containing a list of events
+	err := json.Unmarshal(bMessage, &mapObject)
+	if err == nil {
+		if len(mapObject[expandEventListFromField]) > 0 {
+			for _, ms := range mapObject[expandEventListFromField] {
+				js, err := json.Marshal(ms)
+				if err == nil {
+					messages = append(messages, string(js))
+				} else {
+					a.log.Errorw(fmt.Sprintf("serializing message %s", ms), "error", err)
+				}
+			}
+		}
+	} else {
+		a.log.Debugf("deserializing multiple messages to a `records` object returning error: %s", err)
+		// in some cases the message is an array
+		var arrayObject []interface{}
+		err = json.Unmarshal(bMessage, &arrayObject)
+		if err != nil {
+			// return entire message
+			a.log.Debugf("deserializing multiple messages to an array returning error: %s", err)
+			return []string{string(bMessage)}
+		}
+		for _, ms := range arrayObject {
 			js, err := json.Marshal(ms)
 			if err == nil {
 				messages = append(messages, string(js))

x-pack/filebeat/input/azureeventhub/input_test.go

@@ -10,6 +10,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/elastic/beats/v7/libbeat/logp"
+
 	eventhub "github.com/Azure/azure-event-hubs-go/v3"
 	"github.com/stretchr/testify/assert"
 
@@ -70,17 +72,38 @@ func TestProcessEvents(t *testing.T) {
 }
 
 func TestParseMultipleMessages(t *testing.T) {
+	// records object
 	msg := "{\"records\":[{\"test\":\"this is some message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}," +
 		"{\"test\":\"this is 2nd message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}," +
 		"{\"test\":\"this is 3rd message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}]}"
-	input := azureInput{}
-	messages := input.parseMultipleMessages([]byte(msg))
-	assert.NotNil(t, messages)
-	assert.Equal(t, len(messages), 3)
 	msgs := []string{
 		fmt.Sprintf("{\"test\":\"this is some message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}"),
 		fmt.Sprintf("{\"test\":\"this is 2nd message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}"),
 		fmt.Sprintf("{\"test\":\"this is 3rd message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}")}
+	input := azureInput{log: logp.NewLogger(fmt.Sprintf("%s test for input", inputName))}
+	messages := input.parseMultipleMessages([]byte(msg))
+	assert.NotNil(t, messages)
+	assert.Equal(t, len(messages), 3)
+	for _, ms := range messages {
+		assert.Contains(t, msgs, ms)
+	}
+
+	// array of events
+	msg1 := "[{\"test\":\"this is some message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}," +
+		"{\"test\":\"this is 2nd message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}," +
+		"{\"test\":\"this is 3rd message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}]"
+	messages = input.parseMultipleMessages([]byte(msg1))
+	assert.NotNil(t, messages)
+	assert.Equal(t, len(messages), 3)
+	for _, ms := range messages {
+		assert.Contains(t, msgs, ms)
+	}
+
+	// one event only
+	msg2 := "{\"test\":\"this is some message\",\"time\":\"2019-12-17T13:43:44.4946995Z\"}"
+	messages = input.parseMultipleMessages([]byte(msg2))
+	assert.NotNil(t, messages)
+	assert.Equal(t, len(messages), 1)
 	for _, ms := range messages {
 		assert.Contains(t, msgs, ms)
 	}