feat: Add JSON logging format (#647)

Co-authored-by: Stephen McLaughlin <44235289+Steve-Mcl@users.noreply.github.com>

Author: hardillb

README.md

@@ -113,6 +113,8 @@ Extra options   | Description
 `interval`      | How often, in seconds, the agent checks in with the platform. Default: 60s
 `intervalJitter`| How much, in seconds, to vary the heartbeat +/- `intervalJitter`. Default: 10s
 `moduleCache`   | If the device can not access npmjs.org then use the node modules cache in `module_cache` directory. Default `false`
+`verbose`       | Enables verbose logging
+`jsonLogging`   | Enabled JSON format logs
 
 #### NodeJS options
 
@@ -235,6 +237,8 @@ Extra options   | Description
 ----------------|---------------
 `interval`      | How often, in seconds, the agent checks in with the platform. Default: 60s
 `intervalJitter`| How much, in seconds, to vary the heartbeat +/- `intervalJitter`. Default: 10s
+`verbose`       | Enables verbose logging
+`jsonLogging`   | Enabled JSON format logs
 
 ## Running
 
@@ -278,9 +282,10 @@ Setup command
 
 Global Options
 
-  -h, --help       print out helpful usage information
-  --version        print out version information
-  -v, --verbose    turn on debugging output
+  -h, --help          print out helpful usage information
+  --version           print out version information
+  -v, --verbose       turn on debugging output
+  -j, --json-logging  print logs in JSON format
 ```
 
 ## Running with no access to npmjs.org

lib/cli/args.js

@@ -144,5 +144,12 @@ module.exports = [
         multiple: true,
         typeLabel: '{underline string}',
         group: 'main'
+    },
+    {
+        name: 'json-logging',
+        description: 'output logs in JSON format',
+        type: Boolean,
+        alias: 'j',
+        group: 'global'
     }
 ]

lib/logging/log.js

@@ -4,11 +4,16 @@ const { hasProperty } = require('../utils')
 let buffer
 let mqtt
 let verbose = false
+let jsonLog = false
 
 function log (msg, level) {
     const date = new Date()
-    console.log(`[AGENT] ${date.toLocaleDateString()} ${date.toLocaleTimeString()} [${level || 'info'}] ${msg}`) // eslint-disable-line no-console
     const jsMsg = { level, msg }
+    if (jsonLog) {
+        console.log(JSON.stringify({ ...jsMsg, ts: Date.now() })) // eslint-disable-line no-console
+    } else {
+        console.log(`[AGENT] ${date.toLocaleDateString()} ${date.toLocaleTimeString()} [${level || 'info'}] ${msg}`) // eslint-disable-line no-console
+    }
     if (buffer) {
         buffer.add(jsMsg)
     }
@@ -33,7 +38,11 @@ function NRlog (msg) {
     if (typeof jsMsg.msg !== 'string') {
         jsMsg.msg = JSON.stringify(jsMsg.msg)
     }
-    console.log(`[NR] ${date.toLocaleDateString()} ${date.toLocaleTimeString()} [${jsMsg.level || 'info'}] ${jsMsg.msg}`) // eslint-disable-line no-console
+    if (jsonLog) {
+        console.log(JSON.stringify({ ...jsMsg, ts: Date.now() })) // eslint-disable-line no-console
+    } else {
+        console.log(`[NR] ${date.toLocaleDateString()} ${date.toLocaleTimeString()} [${jsMsg.level || 'info'}] ${jsMsg.msg}`) // eslint-disable-line no-console
+    }
     if (buffer) {
         buffer.add(jsMsg)
     }
@@ -55,6 +64,7 @@ module.exports = {
     initLogger: configuration => {
         verbose = configuration.verbose
         buffer = new LogBuffer(configuration.bufferSize || 1000)
+        jsonLog = configuration.jsonLogging || false
     },
     info: msg => log(msg, 'info'),
     warn: msg => log(msg, 'warn'),

lib/logging/logBuffer.js

@@ -19,9 +19,6 @@ class LogBuffer {
             this.lastLogTimestampCount = 0
         }
         logEntry.ts = logEntry.ts + ('' + this.lastLogTimestampCount).padStart(4, '0')
-        if (logEntry.level === 'system') {
-            console.log(logEntry.msg) // eslint-disable-line no-console
-        }
         this.buffer[this.head++] = logEntry
         if (this.head === this.size) {
             this.head = 0