bunyan wrapper that provides logging defaults for Red Hat Mobile Cloud Applications
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README.md

fh-bunyan

Circle CI

Log factory for applications that want sensible bunyan defaults on the Red Hat Mobile Application Platform.

Example usage:

var bunyan = require('fh-bunyan');

var log = bunyan.getLogger(__filename);

log.info('this is an "info" level log!');

Install

GitHub URL

You can add the following to your package.json, where version is a valid semver tag.

"fh-bunyan": git+https://github.com/evanshortiss/fh-bunyan#{VERSION}

npm

npm install fh-bunyan --save

Configurations

Levels

The logger is configured with some sensible defaults and applies them based on the value of FH_ENV. For example, in dev "trace" will be used. This also applies if your environments are prefixed, e.g ps-dev will also use "trace".

The list below describes the default levels:

  • dev - trace
  • test - debug
  • preprod - info
  • prod - info

Environment Variables

  • BUNYAN_FH_LEVEL - Can be set to control the log level. For example setting this to "info" means "info" level will be used.
  • FH_USE_LOCAL_DB - Not specific to this logger, but if set to a "truthy" value it will cause "trace" logging to be enabled.

Streams

By default, loggers write to stdout and stderr as follows:

  • trace - stdout
  • debug - stdout
  • info - stdout
  • warn - stdout
  • error - stdout & stderr
  • fatal - stdout & stderr

Local Development

During local development trace level logging is always enabled. We check if local development is in effect by checking the FH_USE_LOCAL_DB environment variable is defined and "truthy".

Testing

Log output can be disabled when testing by setting the environment variable NODE_ENV to "test".

Reading Logs

By default, bunyan prints logs in a JSON format which can be difficult to read. These can be made more leigble by piping your program output to bunyan.

For an example, try running the example in this repo:

npm install -g bunyan
node example/index.js | bunyan

This prints output like this:

[2016-03-23T02:54:32.537Z] TRACE: /example/index.js/75394 on eshortiss.local: test trace
[2016-03-23T02:54:32.538Z] DEBUG: /example/index.js/75394 on eshortiss.local: test debug
[2016-03-23T02:54:32.538Z]  INFO: /example/index.js/75394 on eshortiss.local: test info
[2016-03-23T02:54:32.538Z]  WARN: /example/index.js/75394 on eshortiss.local: test warn
[2016-03-23T02:54:32.539Z] ERROR: /example/index.js/75394 on eshortiss.local: error test error
    Error: test error
        at Object.<anonymous> (/Users/eshortiss/workspaces/fh/fh-bunyan/example/index.js:7:11)
        at Module._compile (module.js:456:26)
        at Object.Module._extensions..js (module.js:474:10)
        at Module.load (module.js:356:32)
        at Function.Module._load (module.js:312:12)
        at Function.Module.runMain (module.js:497:10)
        at startup (node.js:119:16)
        at node.js:906:3

API

getLogger(opts)

Returns a Bunyan logger instance that uses preconfigured streams and log levels that are appropriate for our generic environments. opts.name is required, and passing the __filename variable from node.js is often a good idea.

Supported options:

  • name - The name for the logger.
  • streams - An array of bunyan streams.

Examples:

var bunyan = require('fh-bunyan');

// Passing an options Object
var logger = bunyan.getLogger({
  name: 'my-logger'
});

// Passing a name string, no Object
var otherLogger = bunyan.getLogger('my-other-logger');

// Options with name and custom streams
var loggerWithMongoStream = bunyan.getLogger({
  name: 'mongo-logger',
  streams: [require('fh-bunyan-mongo-stream')()]
});

setLogMappings(map)

By default the logger uses the following mappings to determine the logging levels for the given deployment environments:

  • dev - trace
  • test - debug
  • preprod - info
  • prod - info

Use this function if you'd like to change these defaults, but don't want to use the BUNYAN_FH_LEVEL environment variable.

Remember to call this before making calls to getLogger!

Here's an example:

var bunyan = require('fh-bunyan');

// Set our environment to log level map
bunyan.setLogMappings({
  'ps-dev': 'trace',
  'ps-test': 'info'
  'ps-preprod': 'info'
  'ps-prod': process.env.LOG_LEVEL // Example using an env var
});

var log = bunyan.getLogger(__filename);

Contributors

Users below have contributed to this code, or with ideas.

  • evanshortiss
  • j-burlison
  • MikeyBurkman
  • billy-welch

Other folks, if you've been missed from this list open a PR adding yourself.