uci-utils-logger/readme.md

# uCOMmandIt JSON Logger

### json logger based on [pino](getpino.io).

## How to by Example

see [example](./example/example.js) for explanation of options and use in a es6 class allowing logging in any method of the class

```javascript
      // pretty: {translateTime:true, colorize:true, levelFirst:true } // options for pino pretty printer
      // env:'', // 'dev' or 'pro' -- can be use to set/override UCI_ENV environment variable
      // enForce: false, // only used with .env.  if true will override UCI_ENV if it is set, otherwise no
      // level:'info', // info is default level, set level to lowest visible
      // clear: false, // true for log files will clear the current log file on restart
      // logFileName:'test', // if not supplied log filename will be generated from timestamp
      // below properties are optional and are passed to child logger instance and will be part of json log entry
      // libraryName: 'UCI', // will be logged as name:  can be used to identify logs of related packages,  can be set via UCI_LOG_NAME env variable
      appName:'uci-example-logger', //will be used for logging directory name if supplied and will be logged as well
      package: '@uci/logger', // name of package with scope per package.json
      // repo: // will use scope-name from package prop if not supplied
      id: opts.id, // can pass a unique if for easy later search/filtering
      // file: 'example/example.js', // path (to repo root) of actual file running this logger, default is ./src/<package without scope>.js
      class: 'LogTest', // The class that created this logger if any
      // one can pass through additional props to log for every log
      // should not use any keys above or
      //  level,time,msg,pid,hostname
      // logPath,instanceCreatedHR,instanceCreated as keys will be merged
      // NOTE: more props can be added at run time by passing an object of props
      additional: {anotherprop:'test'} // should do not use any keys above or 'level,logPath,package,instanceCreatedHR,instanceCreated' as keys will be merged
```

to run the example clone repo and then `npm install` from root

then

`npm run [script]`

available scripts for example file

"dev": "UCI_ENV=dev ./node_modules/.bin/nodemon -r esm example/example",
"dev:verbose": "UCI_LOG_PRETTY='verbose' npm run dev",
"dev:terse": "UCI_LOG_PRETTY='terse' npm run dev",
"dev:filter:line": "UCI_LOG_PRETTY='{\"filter\":[\"line\"]}' npm run dev",
"dev:include": "UCI_LOG_PRETTY='{\"include\":\"package,appName\"}' npm run dev",
"dev:trace": "UCI_LOG_LEVEL=trace npm run dev",
"dev:warn": "UCI_LOG_LEVEL=warn npm run dev",
"dev:info:only": "UCI_LOG_SEARCH='level==`30`' npm run dev",
"dev:fatal:only": "UCI_LOG_SEARCH='level==`60`' npm run dev",
"dev:json": "UCI_LOG_LEVEL=trace UCI_LOG_JSON=true npm run dev",
"dev:colada": "npm run dev:json | ./node_modules/.bin/pino-colada ",
"pro": "UCI_ENV='pro' node -r esm example/example",
"pro:path": "UCI_LOG_PATH=./example/example.log npm run pro"

## Environment Variables

- `UCI_ENV='dev'|'pro'|'node'`, `dev` outputs to console, `pro` outputs to file, `node` will follow whatever `NODE_ENV` is set to.
- `UCI_LOG_PATH=<some file path>` force logging to go to some particular file, also setable via options, see above
- `UCI_LOG_JSON=true`  will not pretty output to console but rather as raw json.  Useful for piping to a json log processor such as pino-colada
- `UCI_LOG_LEVEL='trace'|'debug'|'info'|'warn'|'error'|fatal'` `warn` is default, can set at runtime with `.lvlset(level)`
- `UCI_LOG_PRETTY`={} the pretty option for pino pretty, also setable via options, see above
- `UCI_LOG_SEARCH='key == `\``value`\``'` will filter pretty/dev logs.  _note:_ ALL search values regardless of type MUST be escaped with ``

## Usage

standalone (not in a class constructor as in example)
lilke this.

import logger from '../src/logger'
opts = {} // see above
let log = logger(opts)

once you have created a Logger as a `global` in your module you can log per http://getpino.io/#/docs/api?id=logger

like so
```javascript
log.trace('this is a trace level logged message')
log.debug('this is a debug level logged message')
log.info({runtimeprop:'somevalue', msg:'this is a info level logged message'})
log.warn('this is a warn level logged message')
log.error('this is a error level logged message')
log.fatal('this is a fatal level logged message')
```


you can change visible levels on the fly http://getpino.io/#/docs/api?id=level

like so

`log.level('debug')`  or in the options, see above


## More Help

this package/model being a simple extension of the pino json logger check their documentation http://getpino.io/#/