New format for custom HTTP headers (#147)

A new format for passing custom HTTP headers using the same syntax as used by InfluxDB output in k6 core.

Author: codebien

pkg/remotewrite/config.go

@@ -180,7 +180,9 @@ func GetConsolidatedConfig(jsonRawConf json.RawMessage, env map[string]string, _
 }
 
 func parseEnvs(env map[string]string) (Config, error) {
-	var c Config
+	c := Config{
+		Headers: make(map[string]string),
+	}
 
 	getEnvBool := func(env map[string]string, name string) (null.Bool, error) {
 		if v, vDefined := env[name]; vDefined {
@@ -231,12 +233,19 @@ func parseEnvs(env map[string]string) (Config, error) {
 
 	envHeaders := getEnvMap(env, "K6_PROMETHEUS_RW_HEADERS_")
 	for k, v := range envHeaders {
-		if c.Headers == nil {
-			c.Headers = make(map[string]string)
-		}
 		c.Headers[k] = v
 	}
 
+	if headers, headersDefined := env["K6_PROMETHEUS_RW_HTTP_HEADERS"]; headersDefined {
+		for _, kvPair := range strings.Split(headers, ",") {
+			header := strings.Split(kvPair, ":")
+			if len(header) != 2 {
+				return c, fmt.Errorf("the provided header (%s) does not respect the expected format <header key>:<value>", kvPair)
+			}
+			c.Headers[header[0]] = header[1]
+		}
+	}
+
 	if b, err := getEnvBool(env, "K6_PROMETHEUS_RW_TREND_AS_NATIVE_HISTOGRAM"); err != nil {
 		return c, err
 	} else if b.Valid {

pkg/remotewrite/config_test.go

@@ -255,8 +255,15 @@ func TestOptionHeaders(t *testing.T) {
 		env     map[string]string
 		jsonRaw json.RawMessage
 	}{
-		"JSON": {jsonRaw: json.RawMessage(`{"headers":{"X-MY-HEADER1":"hval1","X-MY-HEADER2":"hval2"}}`)},
-		"Env":  {env: map[string]string{"K6_PROMETHEUS_RW_HEADERS_X-MY-HEADER1": "hval1", "K6_PROMETHEUS_RW_HEADERS_X-MY-HEADER2": "hval2"}},
+		"JSON": {jsonRaw: json.RawMessage(
+			`{"headers":{"X-MY-HEADER1":"hval1","X-MY-HEADER2":"hval2","X-Scope-OrgID":"my-org-id","another-header":"true","empty":""}}`)},
+		"Env": {env: map[string]string{
+			"K6_PROMETHEUS_RW_HEADERS_X-MY-HEADER1": "hval1",
+			"K6_PROMETHEUS_RW_HEADERS_X-MY-HEADER2": "hval2",
+			// it assert that the new method using HTTP_HEADERS overwrites it
+			"K6_PROMETHEUS_RW_HEADERS_X-Scope-OrgID": "my-org-id-old-method",
+			"K6_PROMETHEUS_RW_HTTP_HEADERS":          "X-Scope-OrgID:my-org-id,another-header:true,empty:",
+		}},
 		//nolint:gocritic
 		//"Arg":  {arg: "headers.X-MY-HEADER1=hval1,headers.X-MY-HEADER2=hval2"},
 	}
@@ -266,8 +273,11 @@ func TestOptionHeaders(t *testing.T) {
 		InsecureSkipTLSVerify: null.BoolFrom(false),
 		PushInterval:          types.NullDurationFrom(5 * time.Second),
 		Headers: map[string]string{
-			"X-MY-HEADER1": "hval1",
-			"X-MY-HEADER2": "hval2",
+			"X-MY-HEADER1":   "hval1",
+			"X-MY-HEADER2":   "hval2",
+			"X-Scope-OrgID":  "my-org-id",
+			"another-header": "true",
+			"empty":          "",
 		},
 		TrendStats:   []string{"p(99)"},
 		StaleMarkers: null.BoolFrom(false),