logger.md

Logger

Anvil Connect uses bunyan for logging.

JSON Example

The default stdout and file streams can be enabled or disabled by editing your JSON configuration file. The default log level is INFO, but it can be specified here too.

{
  // ...
  "logger": {
    "stdout": true,
    "file": true,
    "level": "debug"
  }
}

JavaScript Example

You can also create more sophisticated logging schemes with fine-grained log levels by creating a module called logger.js in the same directory of your project as server.js.

module.exports = {
  name: 'anvilconnect',
  streams: [
    {
      level: 'info',
      stream: process.stdout            // log INFO and above to stdout
    },
    {
      level: 'error',
      path: '/var/tmp/myapp-error.log'  // log ERROR and above to a file
    }
  ]
}

Note: if you are using Docker you will also need to update your Dockerfile to include COPY ./logger.js /opt/connect/logger.js

Configuration Options

Log Level

  level: fatal|error|warn|info|debug|trace

See Bunyan's log level options for more information on the meaning behind these configuration options.

Log Rotation

const logFilePath = path.join(cwd, 'logs', env + '.log')

module.exports = {
  name: 'anvilconnect',
  streams: [
    {
      level: 'info',
      path: logFilePath,
      type: 'rotating-file',
      period: '1d',   // rotation frequency
      count: 10       // number of copies to retain
    }
  ]
}

See Bunyan's log rotation documentation for more information.

Parsing Log Output

Stdout

  # Run Anvil locally and pretty-print all logs.
  node server.js | node_modules/.bin/bunyan
  
  # Run Anvil locally and show 'warn' logs or above.
  node server.js | node_modules/.bin/bunyan -l warn
  
  # Run Anvil locally and ONLY show debug logs.
  node server.js | node_modules/.bin/bunyan -c 'this.level == 20'

Also see Bunyan CLI.