Add docs for prometheus credentials

Author: jrauh01

doc/03-Configuration.md

@@ -48,11 +48,13 @@ Defined in the `notifications` section of the configuration file.
 
 Connection configuration for a Prometheus instance that collects metrics from your Kubernetes cluster,
 from which Icinga for Kubernetes [synchronizes predefined metrics](01-About.md#metric-sync) to display charts in the UI.
-Defined in the `prometheus` section of the configuration file.
+Defined in the `prometheus` section of the configuration file. If one of username or password is set, both must be set.
 
-| Option | Description                                                                          |
-|--------|--------------------------------------------------------------------------------------|
-| url    | **Optional.** Prometheus server URL. If not set, metric synchronization is disabled. |
+| Option   | Description                                                                          |
+|----------|--------------------------------------------------------------------------------------|
+| url      | **Optional.** Prometheus server URL. If not set, metric synchronization is disabled. |
+| username | **Optional.** Prometheus username.                                                   |
+| password | **Optional.** Prometheus password.                                                   |
 
 # Configuration via Environment Variables
 
@@ -90,6 +92,8 @@ The configurations set by environment variables override the ones set by YAML.
 
 ## Prometheus Configuration
 
-| Env            | Description                                                                          |
-|----------------|--------------------------------------------------------------------------------------|
-| PROMETHEUS_URL | **Optional.** Prometheus server URL. If not set, metric synchronization is disabled. |
+| Env                 | Description                                                                          |
+|---------------------|--------------------------------------------------------------------------------------|
+| PROMETHEUS_URL      | **Optional.** Prometheus server URL. If not set, metric synchronization is disabled. |
+| PROMETHEUS_USERNAME | **Optional.** Prometheus username.                                                   |
+| PROMETHEUS_PASSWORD | **Optional.** Prometheus password.                                                   |

pkg/metrics/config.go

@@ -7,8 +7,8 @@ import (
 // PrometheusConfig defines Prometheus configuration.
 type PrometheusConfig struct {
 	Url      string `yaml:"url" env:"URL"`
-	Username string `yaml:"username"`
-	Password string `yaml:"password"`
+	Username string `yaml:"username" env:"USERNAME"`
+	Password string `yaml:"password" env:"PASSWORD"`
 }
 
 // Validate checks constraints in the supplied Prometheus configuration and returns an error if they are violated.