can --inspect be made to bind debug ports for child processes too?

repro steps (I did this on linux and bash):

git clone https://github.com/AndrewJDR/inspect-on-forked-processes-doesnt-work
cd inspect-on-forked-processes-doesnt-work
npm i
npm start

This starts a child process using cluster.fork(). Note that debugger listens fine on the master process:

Debugger listening on ws://127.0.0.1:9229/1ffaac86-3b3f-4097-aa90-df1eba66b6f4
launching child
in the parent: 13039
in the child: 13049

And checking netstat shows that 9229 is indeed bound, which is good.

$ netstat -lnp | grep 9229
tcp        0      0 127.0.0.1:9229          0.0.0.0:*               LISTEN      13039/node      

However, no debugging port is bound for the child process. The output of ps, the --inspect-port=9230 argument would lead one to believe that a debugger port 9230 is available for the child process:

$ ps aux | grep ts-node
13027 pts/30   S+     0:00 sh -c ts-node --inspect -F index.ts
13028 pts/30   Sl+    0:00 node ~/Documents/src/inspect-on-forked-processes-doesnt-work/node_modules/.bin/ts-node --inspect -F index.ts
13039 pts/30   Sl+    0:00 ~/.nvm/versions/node/v9.0.0/bin/node --inspect ~/Documents/src/inspect-on-forked-processes-doesnt-work/node_modules/ts-node/dist/_bin.js -F index.ts
13049 pts/30   Sl+    0:00 ~/.nvm/versions/node/v9.0.0/bin/node ~/Documents/src/inspect-on-forked-processes-doesnt-work/node_modules/ts-node/dist/_bin.js --inspect --inspect-port=9230 ~/Documents/src/inspect-on-forked-processes-doesnt-work/index.ts

However, this is unfortunately not the case, looking at netstat output:

$ netstat -lnp | grep 9230
(.. nothing to see here ..)

Can others reproduce this? If so, can this please be addressed so that we can debug child processes properly?

[AndrewJDR]

I tried process.execArgv.unshift(require('path').join(__dirname, 'bin.js')); and it didn’t work. This is the error I get:

 $ npm start

> inspect-on-forked-processes-doesnt-work@1.0.0 start ~/Documents/src/inspect-on-forked-processes-doesnt-work
> ts-node --inspect index.ts

Debugger listening on ws://127.0.0.1:9229/ed2df97b-b3cd-4f42-a422-16bf231cecd2
For help see https://nodejs.org/en/docs/inspector
launching child
Starting inspector on 127.0.0.1:9229 failed: address already in use
in the parent: 15237

Basically it seems the child tries to bind to the same port as the parent.

[blakeembrey]

The ts-node subprocess has been killed with https://github.com/TypeStrong/ts-node/pull/536.