Add comment for grizzly env variable and add retro compatibility for …

…cortext env variables

pkg/config/config.go

@@ -43,14 +43,33 @@ func override(v *viper.Viper) {
 		"mimir.tenant-id": "MIMIR_TENANT_ID",
 		"mimir.api-key":   "MIMIR_API_KEY",
 	}
+
+	// To keep retro compatibility
+	mimirBindings := map[string]string{
+		"MIMIR_ADDRESS":   "CORTEX_ADDRESS",
+		"MIMIR_TENANT_ID": "CORTEX_TENANT_ID",
+		"MIMIR_API_KEY":   "CORTEX_API_KEY",
+	}
+
 	for key, env := range bindings {
-		val := os.Getenv(env)
-		if val != "" {
+		if val := getVal(env, mimirBindings); val != "" {
 			v.Set(key, val)
 		}
 	}
 }
 
+func getVal(env string, alternativeMap map[string]string) string {
+	if val := os.Getenv(env); val != "" {
+		return val
+	}
+
+	if alternativeMap[env] != "" {
+		return getVal(alternativeMap[env], nil)
+	}
+
+	return ""
+}
+
 func Read() error {
 	err := viper.ReadInConfig()
 	if err != nil {

pkg/mimir/client/http_client.go

@@ -118,6 +118,7 @@ func (c *Client) doRequest(method string, url string, body []byte) ([]byte, erro
 
 func createHttpClient() (*http.Client, error) {
 	timeout := 10 * time.Second
+	// TODO: Move this configuration to the global configuration
 	if timeoutStr := os.Getenv("GRIZZLY_HTTP_TIMEOUT"); timeoutStr != "" {
 		timeoutSeconds, err := strconv.Atoi(timeoutStr)
 		if err != nil {