Namespace support for dynamic environments (#41)

* Update readme cmd and env

* metric namespce support

Author: geekzoo

README.md

@@ -54,22 +54,25 @@ go run main.go
 
 ### Flags
 
-- `locust.uri`
+- `--locust.uri`
   Address of Locust. Default is `http://localhost:8089`.
 
-- `locust.timeout`
+- `--locust.timeout`
   Timeout request to Locust. Default is `5s`.
 
-- `web.listen-address`
+- `--web.listen-address`
   Address to listen on for web interface and telemetry. Default is `:9646`.
 
-- `web.telemetry-path`
+- `--web.telemetry-path`
   Path under which to expose metrics. Default is `/metrics`.
 
-- `log.level`
+- `--locust.namespace`
+  Namespace for prometheus metrics. Default `locust`.
+
+- `--log.level`
   Set logging level: one of `debug`, `info`, `warn`, `error`, `fatal`
 
-- `log.format`
+- `--log.format`
   Set the log output target and format. e.g. `logger:syslog?appname=bob&local=7` or `logger:stdout?json=true`
   Defaults to `logger:stderr`.
 
@@ -89,6 +92,9 @@ The following environment variables configure the exporter:
 - `LOCUST_EXPORTER_WEB_TELEMETRY_PATH`
   Path under which to expose metrics. Default is `/metrics`.
 
+- `LOCUST_METRIC_NAMESPACE`
+  Namespace for prometheus metrics. Default `locust`.
+
 ### Grafana
 
 The grafana dashboard has beed published with ID [11985](https://grafana.com/grafana/dashboards/11985) and was exported to [locust_dashboard.json](locust_dashboard.json).

main.go

@@ -19,8 +19,9 @@ import (
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
-const (
-	namespace = "locust"
+var (
+	namespace string
+	NameSpace *string
 )
 
 // Exporter structure
@@ -419,11 +420,11 @@ func countWorkersByState(stats locustStats, state string) float64 {
 }
 
 func main() {
-
 	var (
 		listenAddress = kingpin.Flag("web.listen-address", "Address to listen on for web interface and telemetry.").Default(":9646").Envar("LOCUST_EXPORTER_WEB_LISTEN_ADDRESS").String()
 		metricsPath   = kingpin.Flag("web.telemetry-path", "Path under which to expose metrics.").Default("/metrics").Envar("LOCUST_EXPORTER_WEB_TELEMETRY_PATH").String()
 		uri           = kingpin.Flag("locust.uri", "URI of Locust.").Default("http://localhost:8089").Envar("LOCUST_EXPORTER_URI").String()
+		NameSpace     = kingpin.Flag("locust.namespace", "Namespace for prometheus metrics.").Default("locust").Envar("LOCUST_METRIC_NAMESPACE").String()
 		timeout       = kingpin.Flag("locust.timeout", "Scrape timeout").Default("5s").Envar("LOCUST_EXPORTER_TIMEOUT").Duration()
 	)
 
@@ -432,6 +433,7 @@ func main() {
 	kingpin.HelpFlag.Short('h')
 	kingpin.Parse()
 
+	namespace = *NameSpace
 	log.Infoln("Starting locust_exporter", version.Info())
 	log.Infoln("Build context", version.BuildContext())