Fix configuration for prometheus address (#2763)

The env variable for prometheus address is not respected as it should be set as
viper default config.

Ticket: https://mattermost.atlassian.net/browse/43295

config.json

@@ -1,8 +1,8 @@
 {
 	"serverRoot": "http://localhost:8000",
-    "port": 8000,
-    "dbtype": "sqlite3",
-    "dbconfig": "./focalboard.db?_busy_timeout=5000",
+	"port": 8000,
+	"dbtype": "sqlite3",
+	"dbconfig": "./focalboard.db?_busy_timeout=5000",
 	"dbtableprefix": "",
 	"postgres_dbconfig": "dbname=focalboard sslmode=disable",
 	"useSSL": false,
@@ -10,7 +10,7 @@
 	"filesdriver": "local",
 	"filespath": "./files",
 	"telemetry": true,
-	"prometheus_address": ":9092",
+	"prometheusaddress": ":9092",
 	"webhook_update": [],
 	"session_expire_time": 2592000,
 	"session_refresh_time": 18000,

docker/config.json

@@ -8,7 +8,7 @@
     "webpath": "./pack",
     "filespath": "./files",
     "telemetry": true,
-    "prometheus_address": ":9092",
+    "prometheusaddress": ":9092",
     "session_expire_time": 2592000,
     "session_refresh_time": 18000,
     "localOnly": false,

server-config.json

@@ -1,14 +1,14 @@
 {
-	"serverRoot": "http://localhost:8000",
-	"port": 8000,
-	"dbtype": "sqlite3",
+    "serverRoot": "http://localhost:8000",
+    "port": 8000,
+    "dbtype": "sqlite3",
     "dbconfig": "./focalboard.db",
-	"postgres_dbconfig": "dbname=focalboard sslmode=disable",
-	"useSSL": false,
-	"webpath": "./pack",
-	"filespath": "./files",
+    "postgres_dbconfig": "dbname=focalboard sslmode=disable",
+    "useSSL": false,
+    "webpath": "./pack",
+    "filespath": "./files",
     "telemetry": true,
-    "prometheus_address": ":9092",
+    "prometheusaddress": ":9092",
     "session_expire_time": 2592000,
     "session_refresh_time": 18000,
     "localOnly": false,

server/services/config/config.go

@@ -40,7 +40,7 @@ type Configuration struct {
 	MaxFileSize              int64             `json:"maxfilesize" mapstructure:"mafilesize"`
 	Telemetry                bool              `json:"telemetry" mapstructure:"telemetry"`
 	TelemetryID              string            `json:"telemetryid" mapstructure:"telemetryid"`
-	PrometheusAddress        string            `json:"prometheus_address" mapstructure:"prometheus_address"`
+	PrometheusAddress        string            `json:"prometheusaddress" mapstructure:"prometheusaddress"`
 	WebhookUpdate            []string          `json:"webhook_update" mapstructure:"webhook_update"`
 	Secret                   string            `json:"secret" mapstructure:"secret"`
 	SessionExpireTime        int64             `json:"session_expire_time" mapstructure:"session_expire_time"`
@@ -95,6 +95,7 @@ func ReadConfigFile(configFilePath string) (*Configuration, error) {
 	viper.SetDefault("AuthMode", "native")
 	viper.SetDefault("NotifyFreqCardSeconds", 120)    // 2 minutes after last card edit
 	viper.SetDefault("NotifyFreqBoardSeconds", 86400) // 1 day after last card edit
+	viper.SetDefault("PrometheusAddress", "")
 
 	err := viper.ReadInConfig() // Find and read the config file
 	if err != nil {             // Handle errors reading the config file