document the logger

[n1ru4l]

We should add better docs on the logger customization.

1. How to customize the logger
2. How to use yoga with common log collecting tools
3. ???

[dthyresson]

@n1ru4l This is a timely issue as I was recently using Yoga with RedwoodJS and there Pino logger and had a few observations:

1. Yoga debug logging is enabled anytime a logger is provided (even a custom one) but there is no way to disable the Yoga log output. See: https://github.com/dotansimha/graphql-yoga/blob/a7834d676f3b45c6761d7f7e259f8c566fcd3994/packages/common/src/server.ts#L272

// Log events - useful for debugging purposes
      enableIf(
        logger !== false,
        useLogger({
          skipIntrospection: true,
          logFn: (eventName, events) => {
            switch (eventName) {
              case 'execute-start':
              case 'subscribe-start':
                this.logger.debug(titleBold('Execution start'))
                const {
                  query,
                  operationName,
                  variables,
                  extensions,
                }: YogaInitialContext = events.args.contextValue
                if (query) {
                  this.logger.debug(
                    '\n' + titleBold('Received GraphQL operation:') + '\n',
                    query,
                  )
                }
                if (operationName) {
                  this.logger.debug('\t operationName:', operationName)
                }
                if (variables) {
                  this.logger.debug('\t variables:', variables)
                }
                if (extensions) {
                  this.logger.debug('\t extensions:', extensions)
                }
                break
              case 'execute-end':
              case 'subscribe-end':
                this.logger.debug(titleBold('Execution end'))
                this.logger.debug('\t result:', events.result)
                break
            }
          },
        }),

2. That means that it is not easy to turn off output like:

May 11, 06:04:01 PM: {"level":20,"time":1652306641686,"pid":9,"hostname":"xxx","msg":"Extracting GraphQL Parameters"}
May 11, 06:04:01 PM: {"level":20,"time":1652306641700,"pid":9,"hostname":"xx","msg":"Processing GraphQL Parameters"}
May 11, 06:04:01 PM: {"level":20,"time":1652306641721,"pid":9,"hostname":"xx,"msg":"\u001b[1mExecution start\u001b[0m"}
May 11, 06:04:01 PM: {"level":20,"time":1652306641724,"pid":9,"hostname":"xxx","msg":"\n\u001b[1mReceived GraphQL operation:\u001b[0m\n"}
May 11, 06:04:01 PM: {"level":20,"time":1652306641725,"pid":9,"hostname":"xx","msg":"\t operationName:"}
May 11, 06:04:01 PM: {"level":20,"time":1652306641725,"pid":9,"hostname":"xx,"msg":"\t variables:"}

In this case using the Pino logger to output NDJSON in a Netlify function

3. Because Pino outputs NDJSON, the formatting with tabs and newlines and bolds are not necessarily needed.

This is a Redwood debug log from the GraphQL Server ... can see a few things: 1) redaction is enabled (we hide the title as en example of log redaction), 2) we have separate keys for data, operationName, query variables etc. 3) we add a name (Pino child logger) to distinguish itself from other logging/logs sent

May 11, 06:04:01 PM: {"level":20,"time":1652306641782,"pid":9,"hostname":"xx","name":"graphql-server","operationName":"BLOG_POSTS","query":{},"data":{"posts":[{"id":150,"title":"[Redacted]","body":"this is some text","createdAt":"2021-08-18T18:00:02.168Z","formattedDate":"6:00 pm on 18th August 2021","__typename":"Post"},{"id":2,"title":"[Redacted]","body":"The wind in the trees is whispering \\ Whispering low that I love her \\ She puts her hand over mine \\ Down in the lime tree arbour","createdAt":"2021-03-18T05:32:39.258Z","formattedDate":"5:32 am on 18th March 2021","__typename":"Post"},{"id":151,"title":"[Redacted]","body":"This is a tests","createdAt":"2022-01-03T15:17:30.505Z","formattedDate":"3:17 pm on 3rd January 2022","__typename":"Post"},{"id":9,"title":"[Redacted]","body":"Great success!","createdAt":"2021-08-06T16:44:22.248Z","formattedDate":"4:44 pm on 6th August 2021","__typename":"Post"},{"id":4,"title":"[Redacted]","body":"Souma Yergon, Sou Nou Yergon \\ We are shakin' the tree \\ Souma Yergon, Sou Nou Yergon \\ We are shakin' the tree","createdAt":"2021-03-18T05:32:39.502Z","formattedDate":"5:32 am on 18th March 2021","__typename":"Post"},{"id":109,"title":"[Redacted]","body":"there","createdAt":"2021-08-18T04:51:11.720Z","formattedDate":"4:51 am on 18th August 2021","__typename":"Post"}]},"msg":"GraphQL execution completed: BLOG_POSTS"}

Suggestions (and perhaps this is a separate issue):

1. Configure Yoga logging separately
2. Configure if the log messages should be "pretty" (tabs, newlines, bolds) or not
3. Note: Redwood may want to setup the child logger earlier so its instance is the Yoga logger (and thus named)

[dthyresson]

2. How to use yoga with common log collecting tools

Pino with their transports is an excellent way to send logs to tools like Datadog and LogFlare.

See: https://getpino.io/#/docs/transports

[ardatan]

• For debug messages debug is called so you can decide when to print in debug method.
• You can get logs however you want with custom logger.
• You can get pretty logs with Pino with the specific plugin https://github.com/pinojs/pino-pretty

[n1ru4l]

https://github.com/dotansimha/graphql-yoga/discussions/1625#discussioncomment-3441299

[enisdenjo]

1806