Allow to customize index name

README.md

@@ -77,7 +77,7 @@ export K6_ELASTICSEARCH_INSECURE_SKIP_VERIFY=true
 ./k6 run ./examples/script.js -o output-elasticsearch
 ```
 
-The metrics are stored in the index `k6-metrics` which will be automatically created by this extension. See the [mapping](pkg/esoutput/mapping.json) for details.
+The metrics are stored in the index `k6-metrics` by default which will be automatically created by this extension. See the [mapping](pkg/esoutput/mapping.json) for details. The index name can be customized with the environment variable `K6_ELASTICSEARCH_INDEX_NAME`.
 
 ## Docker Compose
 
@@ -105,7 +105,7 @@ Clone the repo to get started and follow these steps:
 
 5. Visit http://localhost:5601/ to view results in Kibana (default credentials are `elastic` / `changeme`).
 
-    - Create a [Data View](https://www.elastic.co/guide/en/kibana/current/data-views.html) for the index `k6-metrics`.
+    - Create a [Data View](https://www.elastic.co/guide/en/kibana/current/data-views.html) for the index `k6-metrics` or the index name in `K6_ELASTICSEARCH_INDEX_NAME` if it is set.
         ![Kibana Data View](./images/kibana-data-view.png)
     - Go to [Discover](https://www.elastic.co/guide/en/kibana/current/discover.html) to start exploring the metrics.
         ![Kibana Discover](./images/kibana-discover.png)

pkg/esoutput/config.go

@@ -36,6 +36,7 @@ import (
 
 const (
 	defaultFlushPeriod = time.Second
+	defaultIndexName   = "k6-metrics"
 )
 
 type Config struct {
@@ -50,6 +51,7 @@ type Config struct {
 	ServiceAccountToken null.String `json:"serviceAccountToken" envconfig:"K6_ELASTICSEARCH_SERVICE_ACCOUNT_TOKEN"`
 
 	FlushPeriod types.NullDuration `json:"flushPeriod" envconfig:"K6_ELASTICSEARCH_FLUSH_PERIOD"`
+	IndexName   null.String        `json:"indexName" envconfig:"K6_ELASTICSEARCH_INDEX_NAME"`
 }
 
 func NewConfig() Config {
@@ -63,6 +65,7 @@ func NewConfig() Config {
 		Password:            null.NewString("", false),
 		ServiceAccountToken: null.NewString("", false),
 		FlushPeriod:         types.NullDurationFrom(defaultFlushPeriod),
+		IndexName:           null.StringFrom(defaultIndexName),
 	}
 }
 
@@ -101,6 +104,9 @@ func (base Config) Apply(applied Config) Config {
 	if applied.FlushPeriod.Valid {
 		base.FlushPeriod = applied.FlushPeriod
 	}
+	if applied.IndexName.Valid {
+		base.IndexName = applied.IndexName
+	}
 
 	return base
 }
@@ -148,6 +154,9 @@ func ParseArg(arg string) (Config, error) {
 			return c, err
 		}
 	}
+	if v, ok := params["indexName"].(string); ok {
+		c.IndexName = null.StringFrom(v)
+	}
 
 	return c, nil
 }
@@ -215,6 +224,9 @@ func GetConsolidatedConfig(jsonRawConf json.RawMessage, env map[string]string, a
 	if serviceAccountToken, defined := env["K6_ELASTICSEARCH_SERVICE_ACCOUNT_TOKEN"]; defined {
 		result.ServiceAccountToken = null.StringFrom(serviceAccountToken)
 	}
+	if indexName, defined := env["K6_ELASTICSEARCH_INDEX_NAME"]; defined {
+		result.IndexName = null.StringFrom(indexName)
+	}
 
 	if arg != "" {
 		argConf, err := ParseArg(arg)

pkg/esoutput/esoutput.go

@@ -67,7 +67,7 @@ const hasPrivilegesBody = `{
   "index": [
     {
       "names": [
-        "k6-metrics"
+        "%s"
       ],
       "privileges": [
         "write", "create_index"
@@ -137,21 +137,20 @@ func New(params output.Params) (output.Output, error) {
 		// security is configured on this cluster. Therefore, we call the has privilege API that is guaranteed to work
 		//for every user.
 		if info.StatusCode == 403 {
-			priv, err := client.Security.HasPrivileges(strings.NewReader(hasPrivilegesBody))
+			priv, err := client.Security.HasPrivileges(strings.NewReader(fmt.Sprintf(hasPrivilegesBody, config.IndexName.String)))
 			if err != nil {
 				return nil, err
 			}
 			if priv.StatusCode != 200 {
 				return nil, fmt.Errorf("cannot connect to Elasticsearch (status code %d)", priv.StatusCode)
 			}
-
 		} else {
 			return nil, fmt.Errorf("cannot connect to Elasticsearch (status code %d)", info.StatusCode)
 		}
 	}
 
 	bulkIndexer, err := esutil.NewBulkIndexer(esutil.BulkIndexerConfig{
-		Index:  "k6-metrics",
+		Index:  config.IndexName.String,
 		Client: client,
 		OnError: func(ctx context.Context, err error) {
 			// this happens usually due to permission issues
@@ -175,17 +174,18 @@ func (*Output) Description() string {
 }
 
 func (o *Output) Start() error {
-	res, err := o.client.Indices.Create("k6-metrics", o.client.Indices.Create.WithBody(bytes.NewReader(mapping)))
+	indexName := o.config.IndexName.String
+	res, err := o.client.Indices.Create(indexName, o.client.Indices.Create.WithBody(bytes.NewReader(mapping)))
 	if err != nil {
 		return err
 	}
 	// 400 usually happens when the index already exists, which is ok for our purposes.
 	if res.StatusCode > 400 {
 		body, err := io.ReadAll(res.Body)
 		if err != nil {
-			return fmt.Errorf("could not read response after failure to create index: %v", err)
+			return fmt.Errorf("could not read response after failure to create index %s: %v", indexName, err)
 		}
-		return fmt.Errorf("could not create index k6-metrics: %s", body)
+		return fmt.Errorf("could not create index %s: %s", indexName, body)
 	}
 	res.Body.Close()
 
@@ -194,7 +194,7 @@ func (o *Output) Start() error {
 	} else {
 		o.periodicFlusher = periodicFlusher
 	}
-	o.logger.Debug("Elasticsearch: starting writing to index k6-metrics")
+	o.logger.Debugf("Elasticsearch: starting writing to index %s", indexName)
 
 	return nil
 }