[azureeventhub] SA container: replace underscores(_) with hyphens(-) (#…

…31384)

* SA container: replace underscores(_) with hyphens(-)

When a user specifies an event hub name in the input settings,
the configuration uses it to compose the storage account (SA)
container name.

For example, with an event hub name <EVENT-HUB-NAME>,
the SA container name becomes:

`filebeat-<DATA-STREAM>-<EVENT-HUB-NAME>`
(e.g., `filebeat-auditlogs-eventhub00`).

The Event Hub allows names with underscores (_) characters,
but unfortunately, the SA container does not permit them.

CHANGELOG.next.asciidoc

@@ -119,6 +119,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...main[Check the HEAD dif
 - Add URL Encode template function for httpjson input. {pull}30962[30962]
 - Add `storage_account_container` configuration option to Azure logs. {pull}31279[31279]
 - Add `application/zip` decoder to the `httpsjon` input. {issue}31282[31282] {pull}31304[31304]
+- Sanitize the Azure storage account container names with underscores (_). {pull}31384[31384]
 
 *Auditbeat*
 

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

@@ -10,7 +10,10 @@ package azureeventhub
 import (
 	"errors"
 	"fmt"
+	"strings"
 	"unicode"
+
+	"github.com/elastic/beats/v7/libbeat/logp"
 )
 
 type azureInputConfig struct {
@@ -29,6 +32,7 @@ const ephContainerName = "filebeat"
 
 // Validate validates the config.
 func (conf *azureInputConfig) Validate() error {
+	logger := logp.NewLogger("azureeventhub.config")
 	if conf.ConnectionString == "" {
 		return errors.New("no connection string configured")
 	}
@@ -41,6 +45,20 @@ func (conf *azureInputConfig) Validate() error {
 	if conf.SAContainer == "" {
 		conf.SAContainer = fmt.Sprintf("%s-%s", ephContainerName, conf.EventHubName)
 	}
+	if strings.Contains(conf.SAContainer, "_") {
+		originalValue := conf.SAContainer
+		// When a user specifies an event hub name in the input settings,
+		// the configuration uses it to compose the storage account (SA) container
+		// name (for example, `filebeat-<DATA-STREAM>-<EVENTHUB>`).
+		//
+		// The event hub allows names with underscores (_) characters, but unfortunately,
+		// the SA container does not permit them.
+		//
+		// So instead of throwing an error to the user, we decided to replace
+		// underscores (_) characters with hyphens (-).
+		conf.SAContainer = strings.ReplaceAll(conf.SAContainer, "_", "-")
+		logger.Warnf("replaced underscores (_) with hyphens (-) in the storage account container name (before: %s, now: %s", originalValue, conf.SAContainer)
+	}
 	err := storageContainerValidate(conf.SAContainer)
 	if err != nil {
 		return err

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

@@ -9,6 +9,8 @@ package azureeventhub
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestStorageContainerValidate(t *testing.T) {
@@ -20,6 +22,8 @@ func TestStorageContainerValidate(t *testing.T) {
 		{"a", false},
 		{"a-name-that-is-really-too-long-to-be-valid-and-should-never-be-used-no-matter-what", false},
 		{"-not-valid", false},
+		{"not-valid-", false},
+		{"not--valid", false},
 		{"capital-A-not-valid", false},
 		{"no_underscores_either", false},
 	}
@@ -30,3 +34,26 @@ func TestStorageContainerValidate(t *testing.T) {
 		}
 	}
 }
+
+func TestValidate(t *testing.T) {
+	t.Run("Sanitize storage account containers with underscores", func(t *testing.T) {
+		config := azureInputConfig{
+			ConnectionString: "sb://test-ns.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=SECRET",
+			EventHubName:     "event_hub_00",
+			SAName:           "teststorageaccount",
+			SAKey:            "secret",
+			SAContainer:      "filebeat-activitylogs-event_hub_00",
+		}
+
+		if err := config.Validate(); err != nil {
+			t.Fatalf("unexpected validation error: %v", err)
+		}
+
+		assert.Equal(
+			t,
+			"filebeat-activitylogs-event-hub-00",
+			config.SAContainer,
+			"underscores (_) not replaced with hyphens (-)",
+		)
+	})
+}