Im a little confused with all this nodejs debug syntax flying around.
I simply want to start the debugger on a process when I run it on a different port.
Normally I start debugging by node debug file.js
but now I have to process` running that I need to debug
Now I found the command node --debugger=7873 file.js but that starts the debugger and jumps past all the breaks and I tried node --debugger=7837 --debug-brk file.js but that forces me to consume another teminal window. How can I just run a script on a different port in the same terminal or with out using nohup?
node debug --port=[your port] your_program.js
responsible _debugger code here
Related
Using the instructions found here I have setup Visual Studio Code to debug my nodejs code.
But it takes the debugger a few seconds to attach to node. And during that few seconds the code just runs.
So a file like this, with a breakpoint on line 1:
• 1 console.log('')
Will never break because it quits before the debugger attaches.
I can quickly ^c the code then restart and sometimes catch the debugger but this is unreliable.
Is there an event I can wait for in my code so that I know the debugger is attached and it is safe to continue?
Or is there a better configuration for doing this?
Yes, using the --inspect-brk option for node instead of --inspect.
so when running your code it would look something like this
node --inspect-brk server.js
I am trying to debug my Discord bot using the DiscordJS lib. My trouble is that when I start a debug session (launching with vscode or with --inspect-brk | --debug-brk)
I get a Starting inspector on 127.0.0.1:42457 failed: address already in use error I have tried changing the port in both situations and still getting the same error on different ports. My bot is sharded so its start child process of itself. I have tried using vscode to attach to child processes but still the same error.
If anybody is familiar with DiscordJS and knows how to debug a sharded bot some help would be much appreciated
In my case to solve this, just add that config on nodemon.json
{
"execMap": {
"js": "node --inspect=9300 -r sucrase/register"
}
}
I added --inspect=9300 to set port to this specific port
First Ctrl C (or Cmd C) to quit all your progress in the cmd.
Start Task Manager > Find all tasks named "node" > End process.
Now go back to your cmd and start server.
That is because you are already running that application in with node filename.js, hence stop that process and start with debugging again with same port.
You can take a look that on the below video might help
https://www.youtube.com/watch?v=b8e9RAekktY&t=28s
I am trying to debug my intern test using node inspector. I followed all the steps correctly from here. I gave it a run by performing the following command
Start Selenium[for intern test]
Run the intern test in node environment
C:\node\node --debug-brk node_modules/intern/runner.js config=tests/intern
In another cmd I run the node inspector
node-inspector --web-port=9999 &
Start the browser
http://127.0.0.1:9999/?ws=127.0.0.1:9999&port=5858
I can see all the script of my project. I have break point set in one of the test component. But the moment I resume the debugger the test start running but the breakpoint is never hit. What am I doing wrong ?
I think you should add debugger; into your script as a break point
I have added the configuration in the launch.json file with the following details :
{
"name": "Attach"
"type": "node",
// TCP/IP address. Default is "localhost".
"address": "localhost",
// Port to attach to.
"port": 5858
}
Now I start my app with the following command : node --debug-brk ./bin/www
When i go to VSCode and select Attach in the debugging menu on the top and click on the play button.
It attaches, but when i go to browser and open a page, it doesn't it the breakpoint or the handler function in my index.js file.
Can you please help what could be going wrong?
There are two issues with breakpoints in node (and these issues are not specific to VSCode but you can see them in node-inspector as well):
If you set breakpoints in your app's startup code and launch node with --debug (opposed to --debug-brk), node starts immediately and has executed your startup code before VSCode had a chance to register the breakpoints. So if you need to debug startup code use the --debug-brk flag because it allows VSCode to set breakpoints before node starts the application.
Node does not parse source files completely on load but delays parsing of closures (callbacks etc.) until their code is first hit. As a consequence breakpoints set on callbacks are not always correctly registered by node, because it does not have parsed the code yet. This 'lazy' behaviour can be disabled by starting node with the --nolazy flag.
In the next version of VSCode (0.4.0) we try to address these problem as follows:
VScode will always launch node with the --debug-brk flag but will hide the first stop and continue if the user did not specify "stopOnEntry: true". This will avoid problems with missed breakpoints in startup code.
If breakpoints are set in code that has not been parsed by node, node will register them at the next possible position in parsed code. Since these "actual" positions are returned by node to the client, VSCode is able to show these positions. So the user will see that a breakpoint set in an unparsed callback "jumps" to a position further down and he will better understand why the debugger is not stopping at the location requested. In addition we added a "Reapply" button to the breakpoint view which makes it really easy to clear and set all breakpoints.
Your breakpoints are probably set too early and are not registered by node. It should help if you set the breakpoints after you have attached.
We have improved this experience in VSCode and it should be available in 0.4.0
Always clear your breakpoints and set them after you attach. I learned the hard way. This is certainly a bug.
I've been digging into this and here is what I have found so far for 0.3.0.
This does not work!
In Code add a breakpoint to app.js or a route
In terminal run node --debug src/server/app.js
In Code attach the debugger
This works!
In terminal run node --debug src/server/app.js
In Code remove all breakpoints
In Code add a breakpoint to app.js or a route
In Code attach the debugger
This does not work, as --debug doesn't kick in unless its the arg after node and before the file
In terminal run node src/server/app.js --debug
In Code remove all breakpoints
In Code add a breakpoint to app.js or a route
In Code attach the debugger
This works, assuming you have a gulp process
In terminal run gulp serve-dev --debug
In Code remove all breakpoints
In Code add a breakpoint to app.js or a route
In Code attach the debugger
This does not work, sometimes
In terminal run gulp serve-dev --debug
In Code add a breakpoint to app.js or a route
In Code attach the debugger
Why sometimes? The best I can tell is that that the breakpoints sometimes get funky. Sometimes they work fine, and other times I have to remove them and re-add them before attaching the debugger.
I am trying to debug the child_process example from here using IntelliJ IDEA 12.1.3 and node 10.10. When I run nodejs app.js from a terminal everything works. The console output displays as expected. However, when I debug the same script using IDEA there are no messages in console output and the app just sits there. This is what is in the console window:
/usr/bin/nodejs --debug-brk=58954 app.js
debugger listening on port 58954
debugger listening on port 58954
When I run the script in IDEA without the debugger attached, the script works as expected.
Why does attaching the debugger break the script?
You can force the children to use a free port for debugging. InteliJ will automatically pick up the port chosen by the child process.
Here's an example:
// Determine if in debug mode.
// If so, pass in a debug-brk option manually, without specifying port.
var startOpts = {};
var isInDebugMode = typeof v8debug === 'object';
if(isInDebugMode) {
startOpts = {execArgv: ['--debug-brk']};
}
child_process.fork('./some_module.js', startArgs, startOpts);
looks like a bug in node.js fork to me: both parent and child processes receive --debug-brk=58954 switch and attempt to start debugger and listen port 58954.