Adding the ability to configure Winston's file transport logging level.

Author: airdrummingfool

_config.yml

@@ -24,3 +24,6 @@ mqtt:
 
 # Port number to listen on
 port: 8080
+
+# Log level for Winston's file transports (set to `error` to reduce logging to a minimum)
+# winston_file_log_level: error

server.js

@@ -34,6 +34,7 @@ var CONFIG_DIR = process.env.CONFIG_DIR || process.cwd(),
     // The topic type to send state changes to smartthings
     TOPIC_WRITE_STATE = 'set_state',
     SUFFIX_WRITE_STATE = 'state_write_suffix',
+    WINSTON_FILE_LOG_LEVEL = 'winston_file_log_level',
     RETAIN = 'retain';
 
 var app = express(),
@@ -137,6 +138,11 @@ function migrateState (version) {
         config.port = 8080;
     }
 
+    // Default file transport logging level
+    if (!config[WINSTON_FILE_LOG_LEVEL]) {
+        config[WINSTON_FILE_LOG_LEVEL] = 'info';
+    }
+
     // Default protocol
     if (!url.parse(config.mqtt.host).protocol) {
         config.mqtt.host = 'mqtt://' + config.mqtt.host;
@@ -323,6 +329,8 @@ async.series([
         winston.info('Perfoming configuration migration');
         migrateState(state.version);
 
+        winston.default.transports.file.level = config[WINSTON_FILE_LOG_LEVEL];
+
         process.nextTick(next);
     },
     function connectToMQTT (next) {