mercurius-logging

This plugin add a Log with all the GraphQL details you need.

The issue

By default, Fastify logs a simple request that shows always the same url:

{
  "level": 30,
  "time": 1660395516356,
  "pid": 83316,
  "hostname": "eomm",
  "name": "gateway",
  "reqId": "req-1",
  "req": {
    "method": "POST",
    "url": "/graphql",
    "hostname": "localhost:60767",
    "remoteAddress": "127.0.0.1",
    "remotePort": 60769
  },
  "msg": "incoming request"
}

This output does not let you know which queries or mutations are being executed, unless you print or inspect the GQL payload.

This plugin adds this log output to your application:

{
  "level": 30,
  "time": 1660395516406,
  "pid": 83316,
  "hostname": "eomm",
  "name": "gateway",
  "reqId": "req-1",
  "graphql": {
    "queries": [
      "myTeam",
      "myTeam"
    ]
  }
}

When the request contains some mutations:

{
  "level": 30,
  "time": 1660395516406,
  "pid": 83316,
  "hostname": "eomm",
  "name": "gateway",
  "reqId": "req-1",
  "graphql": {
    "mutations": [
      "resetCounter"
    ]
  }
}

Here a complete example when you turn on all the log options:

{
  "level": 30,
  "time": 1660395516406,
  "pid": 83316,
  "hostname": "eomm",
  "name": "gateway",
  "reqId": "req-1",
  "graphql": {
    "queries": [
      "a:add",
      "b:add",
      "c:add",
      "d:add"
    ],
    "operationName": "baam",
    "body": "
      query boom($num: Int!) {
        a: add(x: $num, y: $num)
        b: add(x: $num, y: $num)
      }
      query baam($num: Int!, $bin: Int!) {
        c: add(x: $num, y: $bin)
        d: add(x: $num, y: $bin)
    }",
    "variables": {
      "num": 2,
      "bin": 3
    }
  }
}

If the mercurius graphql decorator is used, it is necessary to provide a context object: app.graphql(query, { reply }). Otherwise, this plugin will ignore the request.

Install

npm install mercurius-logging

Compatibility

Plugin version	Fastify version
^2.0.0	^5.0.0
^1.0.0	^4.0.0

Usage

const Fastify = require('fastify')
const mercurius = require('mercurius')
const mercuriusLogging = require('mercurius-logging')

const app = Fastify({
  logger: true,
  disableRequestLogging: true
})

app.register(mercurius, {
  schema: yourSchema,
  resolvers: yourResolvers
})
app.register(mercuriusLogging)

Options

You can customize the output of the plugin by passing an options object:

app.register(mercuriusLogging, {
  logLevel: 'debug', // default: 'info'
  prependAlias: true, // default: false
  logBody: true, // default: false
  logVariables: true, // default: false
  logRequest: true // default: false
  logMessage: function(context) // default: undefined
})

logLevel

The log level of the plugin. Note that the request logger is used, so you will get the additional request data such as the reqId.

logRequest

Add to the log line the req: request object. This is useful if you want to log the request's headers or other. You can customize what to log by using the logSerializers option of Fastify.

const app = Fastify({
  logger: {
    level: 'debug',
    serializers: {
      req: function reqSerializer (req) {
        // look at the standard serializer for the req object:
        // https://github.com/pinojs/pino-std-serializers/
        return {
          headers: req.headers
        }
      }
    }
  }
})

app.register(mercuriusLogging, {
  logRequest: true
})

prependAlias

Queries and mutations may have an alias. If you want to append the alias to the log, set this option to true. You will get the following output:

{
  "level": 30,
  "graphql": {
    "queries": [
      "firstQuery:myTeam",
      "secondQuery:myTeam"
    ]
  }
}

logBody

If you want to include the body of the request in the log output, set this option to true.

You can provide a syncronous function to choose to log the body or not. The function must return true to log the body.

app.register(mercuriusLogging, {
  logBody: function (context, body) {
    return context.reply.request.headers['x-debug'] === 'true'
  }
})

Here an output example:

{
  "level": 30,
  "graphql": {
    "queries": [
      "firstQuery:myTeam",
      "secondQuery:myTeam"
    ],
    "body": "query firstQuery { myTeam { name } } query secondQuery { myTeam { name } }"
  }
}

logVariables

If you want to include the request's variables in the log output, set this option to true.

{
  "level": 30,
  "graphql": {
    "queries": [
      "firstQuery:myTeam",
      "secondQuery:myTeam"
    ],
    "variables": {
      "teamId": 1
    }
  }
}

logMessage

If you want to put a custom message inside the log output, you can set this option as a function(context) which returns a string or an array containing Pino supported values.

Example returning a string

app.register(mercuriusLogging, {
  logMessage: function (context) {
    return `This is a request made with method ${context.reply.request.method}`
  }
})

Here's an output example

{
  "level": 30,
  "graphql": {
    "queries": [
      "firstQuery:myTeam",
      "secondQuery:myTeam"
    ]
  },
  "msg": "This is a request made with method POST"
}

Example returning an array

app.register(mercuriusLogging, {
  logMessage: function (context) {
    return ['This is a request made with method %s by foo%s', context.reply.request.method, 'bar' ]
  }
})

Here's an output example

{
  "level": 30,
  "graphql": {
    "queries": [
      "firstQuery:myTeam",
      "secondQuery:myTeam"
    ]
  },
  "msg": "This is a request made with method POST by foobar"
}

License

Copyright Manuel Spigolon, Licensed under MIT.