Merge pull request #61 from ong-gtp/dev

Adapt logging to Heroku's logging technique

Author: cham11ng

.env.docker

@@ -12,6 +12,7 @@ DB_PASSWORD=secret
 
 # Log
 LOGGING_LEVEL=debug
+LOG_FILE_GENERATION_SUPPORT=false
 
 # Authentication
 ACCESS_TOKEN_DURATION=10m

.env.example

@@ -12,6 +12,7 @@ DB_PASSWORD=
 
 # Log
 LOGGING_LEVEL=debug
+LOG_FILE_GENERATION_SUPPORT=false
 
 # Authentication
 ACCESS_TOKEN_DURATION=10m

src/config/config.ts

@@ -31,7 +31,8 @@ export default {
     level: process.env.LOGGING_LEVEL || 'info',
     maxSize: process.env.LOGGING_MAX_SIZE || '20m',
     maxFiles: process.env.LOGGING_MAX_FILES || '7d',
-    datePattern: process.env.LOGGING_DATE_PATTERN || 'YYYY-MM-DD'
+    datePattern: process.env.LOGGING_DATE_PATTERN || 'YYYY-MM-DD',
+    logFileGenarationSupport: process.env.LOG_FILE_GENERATION_SUPPORT || 'true'
   },
   db: {
     client: process.env.DB_CLIENT,

src/utils/logger.ts

@@ -1,6 +1,6 @@
 import fs from 'fs';
 import DailyRotateFile from 'winston-daily-rotate-file';
-import { createLogger, format, transports } from 'winston';
+import { createLogger, format, transports, Logger } from 'winston';
 
 import context from './context';
 import app from '../config/config';
@@ -29,29 +29,43 @@ const formatter = printf((info: any) => {
   return `[ ${ts} ] [ ${transactionId} ] - [ ${level} ] ${message} ${meta}`;
 });
 
-if (!fs.existsSync('logs')) {
-  fs.mkdirSync('logs');
-}
-
 let trans: any = [];
+let logger: Logger;
 
-if (environment === 'development') {
-  trans = [new transports.Console()];
-}
+/*
+ Send logs to console if log file generation is not supported.
+ Heroku is an example cloud service provider that uses plug-ins to monitor logs 
+ and logs are sent to console. Accessing the log files generated by the app poses a difficult task.
+ */
+if (logging.logFileGenarationSupport === 'false') {
+  logger = createLogger({
+    level: logging.level,
+    format: combine(splat(), colorize(), timestamp(), formatter),
+    transports: [new transports.Console()]
+  });
+} else {
+  if (!fs.existsSync('logs')) {
+    fs.mkdirSync('logs');
+  }
 
-const logger = createLogger({
-  level: logging.level,
-  format: combine(splat(), colorize(), timestamp(), formatter),
-  transports: [
-    ...trans,
-    new DailyRotateFile({
-      maxSize: logging.maxSize,
-      maxFiles: logging.maxFiles,
-      datePattern: logging.datePattern,
-      zippedArchive: true,
-      filename: `logs/${logging.level}-%DATE%.log`
-    })
-  ]
-});
+  if (environment === 'development') {
+    trans = [new transports.Console()];
+  }
+
+  logger = createLogger({
+    level: logging.level,
+    format: combine(splat(), colorize(), timestamp(), formatter),
+    transports: [
+      ...trans,
+      new DailyRotateFile({
+        maxSize: logging.maxSize,
+        maxFiles: logging.maxFiles,
+        datePattern: logging.datePattern,
+        zippedArchive: true,
+        filename: `logs/${logging.level}-%DATE%.log`
+      })
+    ]
+  });
+}
 
 export default logger;