Properly load creds from env and save them when server cmd is executed (#2970)

cmd/main.go

@@ -174,6 +174,23 @@ func Main() {
 		err := initConfig()
 		fatalIf(err, "Unable to initialize minio config.")
 
+		// Fetch access keys from environment variables and update the config.
+		accessKey := os.Getenv("MINIO_ACCESS_KEY")
+		secretKey := os.Getenv("MINIO_SECRET_KEY")
+		if accessKey != "" && secretKey != "" {
+			if !isValidAccessKey.MatchString(accessKey) {
+				fatalIf(errInvalidArgument, "Invalid access key.")
+			}
+			if !isValidSecretKey.MatchString(secretKey) {
+				fatalIf(errInvalidArgument, "Invalid secret key.")
+			}
+			// Set new credentials.
+			serverConfig.SetCredential(credential{
+				AccessKeyID:     accessKey,
+				SecretAccessKey: secretKey,
+			})
+		}
+
 		// Enable all loggers by now.
 		enableLoggers()
 

cmd/server-main.go

@@ -174,28 +174,11 @@ func initServerConfig(c *cli.Context) {
 		fatalIf(err, "Unable to convert MINIO_CACHE_EXPIRY=%s environment variable into its time.Duration value.", cacheExpiryStr)
 	}
 
-	// Fetch access keys from environment variables if any and update the config.
-	accessKey := os.Getenv("MINIO_ACCESS_KEY")
-	secretKey := os.Getenv("MINIO_SECRET_KEY")
-
-	// Validate if both keys are specified and they are valid save them.
-	if accessKey != "" && secretKey != "" {
-		if !isValidAccessKey.MatchString(accessKey) {
-			fatalIf(errInvalidArgument, "Invalid access key.")
-		}
-		if !isValidSecretKey.MatchString(secretKey) {
-			fatalIf(errInvalidArgument, "Invalid secret key.")
-		}
-
-		// Set new credentials.
-		serverConfig.SetCredential(credential{
-			AccessKeyID:     accessKey,
-			SecretAccessKey: secretKey,
-		})
-
-		// Save new config.
+	// When credentials inherited from the env, server cmd has to save them in the disk
+	if os.Getenv("MINIO_ACCESS_KEY") != "" && os.Getenv("MINIO_SECRET_KEY") != "" {
+		// Env credentials are already loaded in serverConfig, just save in the disk
 		err = serverConfig.Save()
-		fatalIf(err, "Unable to save config.")
+		fatalIf(err, "Unable to save credentials in the disk.")
 	}
 
 	// Set maxOpenFiles, This is necessary since default operating