fixed authorization header and readme edits

README.md

@@ -59,21 +59,23 @@ Help:
 
 ```
 $ sensu-prometheus-collector -h
-Usage of sensu-prometheus-collector:
+Usage of ./sensu-prometheus-collector:
+  -exporter-authorization string
+        Prometheus exporter Authorization header.
   -exporter-password string
-    	Prometheus exporter basic auth password
+        Prometheus exporter basic auth password.
   -exporter-url string
-    	Prometheus exporter URL to pull metrics from.
+        Prometheus exporter URL to pull metrics from.
   -exporter-user string
-    	Prometheus exporter basic auth user
+        Prometheus exporter basic auth user.
   -metric-prefix string
-    	Metric name prefix, only supported by line protocol output formats.
+        Metric name prefix, only supported by line protocol output formats.
   -output-format string
-    	The check output format to use for metrics {influx|graphite|json}. (default "influx")
+        The check output format to use for metrics {influx|graphite|json}. (default "influx")
   -prom-query string
-    	Prometheus API query string. (default "up")
+        Prometheus API query string. (default "up")
   -prom-url string
-    	Prometheus API URL. (default "http://localhost:9090")
+        Prometheus API URL. (default "http://localhost:9090")
 ```
 
 Application instrumentation:

sensu-prometheus-collector.go

@@ -21,6 +21,12 @@ const (
 	exporterAuthID = "exporter"
 )
 
+type ExporterAuth struct {
+	User     string `envconfig:"user" default:""`
+	Password string `envconfig:"password" default:""`
+	Header   string `envconfig:"header" default:""`
+}
+
 type Tag struct {
 	Name  model.LabelName
 	Value model.LabelValue
@@ -31,12 +37,6 @@ type Metric struct {
 	Value float64
 }
 
-type ExporterAuth struct {
-	User     string `envconfig:"user" default:""`
-	Password string `envconfig:"password" default:""`
-	Header   string `envconfig:"header" default:""`
-}
-
 func CreateJSONMetrics(samples model.Vector) string {
 	metrics := []Metric{}
 
@@ -210,7 +210,7 @@ func setExporterAuth(user string, password string, header string) (auth Exporter
 		auth.Password = password
 	}
 
-	if auth.Header != "" {
+	if header != "" {
 		auth.Header = header
 	}