@jackdbd/tags-logger

A logger inspired by how logging is implemented in Hapi.js.

• Features
• Installation
• Usage
  • structured logging
  • unstructured logging
• Configuration
  • Environment variables
  • Options
• API

Features

• tags to pinpoint the log statements you are actually interested in.
• optional validation of all log statements with Joi.
• easy switching bewteen structured/unstructured logging.

Installation

npm install @jackdbd/tags-logger

Usage

structured logging

When you write this:

import makeLog from '@jackdbd/tags-logger'

const log = makeLog()

log({
  message: 'something not very important about foo and bar',
  tags: ['debug', 'foo', 'bar']
})

log({
  message: 'something of critical importance about baz',
  tags: ['critical', 'baz']
})

You get this:

{
  "severity": "DEBUG",
  "message": "something not very important about foo and bar",
  "tags": ["bar", "foo"],
  "tag": {"bar": true, "foo": true}
}

{
  "severity": "CRITICAL",
  "message": "something of critical importance about baz",
  "tags": ["baz"],
  "tag": {"baz": true}
}

unstructured logging

When you write this:

import makeLog from '@jackdbd/tags-logger'

const log = makeLog({
  namespace: 'my-app/my-module'
})

// same log statements as above

You get this (but with colors):

my-app/my-module [🔍 bar,foo] something not very important about foo and bar +0ms

my-app/my-module [🔥 baz] something of critical importance about baz +0ms

Don't like emojis? Then write this:

import makeLog from '@jackdbd/tags-logger'

const log = makeLog({
  namespace: 'my-app/my-module',
  should_use_emoji_for_severity: false // <--
})

// same log statements as above

And get this (but with colors):

my-app/my-module [debug bar,foo] something not very important about foo and bar +0ms

my-app/my-module [critical baz] something of critical importance about baz +0ms

Configuration

Environment variables

| Environment variable | Explanation | | --- | --- | | DEBUG | You must set this environment variable if you want to use unstructured logging and see some output. This library delegates unstructured logging to debug.

Options

| Option | Default | Explanation | | --- | --- | --- | | namespace | undefined | The namespace for unstructured logging. This option has no effect when using structured logging. | | should_use_emoji_for_severity | true | Whether to use an emoji for the severity level, when using unstructured logging. This option has no effect when using structured logging. | | should_validate_log_statements | false when process.env.NODE_ENV === 'production'. Otherwise true | Whether each log statement should be validated against a Joi schema. |

API

API docs generated with TypeDoc