Merge pull request #7 from chatwork/readme-username-option

Add a detailed description to `sendgrid.username` option

README.md

@@ -28,9 +28,9 @@ Flags:
                               Address to listen on for web interface and telemetry.
       --web.disable-exporter-metrics
                               Exclude metrics about the exporter itself (promhttp_*, process_*, go_*).
-      --sendgrid.username=""  Set SendGrid username
       --sendgrid.api-key="secret"
-                              Set SendGrid API key
+                              [Required] Set SendGrid API key
+      --sendgrid.username=""  [Optional] Set SendGrid username as a label for each metrics. This is for identifying multiple SendGrid users metrics.
       --log.level=info        Only log messages with the given severity or above. One of: [debug, info, warn, error]
       --log.format=logfmt     Output format of log messages. One of: [logfmt, json]
       --version               Show application version.

main.go

@@ -36,14 +36,14 @@ var (
 		"web.disable-exporter-metrics",
 		"Exclude metrics about the exporter itself (promhttp_*, process_*, go_*).",
 	).Envar("DISABLE_EXPORTER_METRICS").Bool()
-	sendGridUserName = kingpin.Flag(
-		"sendgrid.username",
-		"Set SendGrid username",
-	).Default("").Envar("SENDGRID_USER_NAME").String()
 	sendGridAPIKey = kingpin.Flag(
 		"sendgrid.api-key",
-		"Set SendGrid API key",
+		"[Required] Set SendGrid API key",
 	).Default("secret").Envar("SENDGRID_API_KEY").String()
+	sendGridUserName = kingpin.Flag(
+		"sendgrid.username",
+		"[Optional] Set SendGrid username as a label for each metrics. This is for identifying multiple SendGrid users metrics.",
+	).Default("").Envar("SENDGRID_USER_NAME").String()
 )
 
 func main() {