Where does the output from graphql-codegen go, if not stderr or stdout?

[erikpukinskis]

Probably a stupid question, and I'm missing something totally basic about how shells work, but this is really baffling me!

I'm trying to use graphql-codegen with pm2, but when capturing lots pm2 expects output to go to stderr or stdout. The output from graphql-codegen seems to go... somewhere else?

Like, if I run the raw command, I get a nice error message that tells me "Please make sure that your codegen config file contains the "generates" field":

pioneers-of-return: /tmp echo "broken" > codegen.yml
pioneers-of-return: /tmp graphql-codegen
  ✖ Parse configuration
    → Invalid Codegen Configuration!
    Generate outputs
  Invalid Codegen Configuration!

        Please make sure that your codegen config file contains the "generates" field, with a specification for the plugins you need.

        It should looks like that:

        schema:
          - my-schema.graphql
        generates:
          my-file.ts:
            - plugin1
            - plugin2
            - plugin3
        
Error: Invalid Codegen Configuration!
    at normalize (/Users/some_eriks/.config/yarn/global/node_modules/@graphql-codegen/cli/bin.js:952:19)
    at Task.task (/Users/some_eriks/.config/yarn/global/node_modules/@graphql-codegen/cli/bin.js:1003:21)
    at /Users/some_eriks/.config/yarn/global/node_modules/listr/lib/task.js:167:30
Invalid Codegen Configuration!

But if I try to capture that output I don't get any of that info:

pioneers-of-return: /tmp graphql-codegen > stdout 2> stderr
pioneers-of-return: /tmp cat stdout
[18:36:51] Parse configuration [started]
[18:36:51] Parse configuration [failed]
[18:36:51] → Invalid Codegen Configuration!
pioneers-of-return: /tmp cat stderr
Invalid Codegen Configuration!

What's going on here? I don't understand how that output is showing up in the shell if its not going through stderr or stdout?

[erikpukinskis]

Well, I made a little bit of progress here, I have a theory, which is that graphql-codegen uses listr and listr suppresses all output for the individual commands.

Well "suppresses"... it still manages to appear in the console, which I don't understand. But it suppresses it ever making it to stdout or stderr.

I guess my next step is to try to duplicate that behavior with a small listr demo.

[erikpukinskis]

Ayyy! Found a workaround!

I still have no understanding of why this is happening in the first place. I did see there's a custom Lister renderer in https://github.com/dotansimha/graphql-code-generator/blob/master/packages/graphql-codegen-cli/src/utils/listr-renderer.ts. Which probably has something to do with it?

But the workaround is to use the Linux script command:

script -a out
graphql-codegen
exit
cat out

That creates an entire new shell, runs the command in it, and allows you to capture the output. Nice!

Seems like this might work with pm2. I will try to write a script that silently starts up the script session, and then tails the output?

Edit: Even easier than that, I can just pipe the command to script and that redirects everything to stdout so pm2 can log it:

pioneers-of-return: /tmp echo "graphql-codegen" | script > out
pioneers-of-return: /tmp cat out 
graphql-codegen
^D
The default interactive shell is now zsh.
To update your account to use zsh, please run `chsh -s /bin/zsh`.
For more details, please visit https://support.apple.com/kb/HT208050.
pioneers-of-return: /tmp graphql-codegen
  ✖ Parse configuration
   
    Generate outputs
  Invalid Codegen Configuration!

        Please make sure that your codegen config file contains the "generates" 
field, with a specification for the plugins you need.

        It should looks like that:

        schema:
          - my-schema.graphql
        generates:
          my-file.ts:
            - plugin1
            - plugin2
            - plugin3
        
Error: Invalid Codegen Configuration!
    at normalize (/Users/some_eriks/.config/yarn/global/node_modules/@graphql-co
degen/cli/bin.js:952:19)
    at Task.task (/Users/some_eriks/.config/yarn/global/node_modules/@graphql-co
degen/cli/bin.js:1003:21)
    at /Users/some_eriks/.config/yarn/global/node_modules/listr/lib/task.js:167:
30
Invalid Codegen Configuration!
pioneers-of-return: /tmp exit
Script started, output file is typescript

Script done, output file is typescript

So all I need to do in my pm2 config is run echo "graphql-codegen" | script instead of graphql-codegen