I am trying to debug a node application, I have placed break point in chrome://inspect. But I am surprised on starting node application it doesn't stop at that break point.
I have ran these commands node --inspect app.js then chrom://inspect to set break points
Related
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.
How can I debug a running nodejs app? I've found tools such as node-inspector, but it seems to only support starting the app and debugging from there.
Debugging a running nodejs app.
This is the combination of a little documented feature of V8 mixed with a non-documented feature of the node.js debugger client. Say you have an already running node process that you want to debug.
# start the remote debugger in the already running node process
kill -s USR1 pid
# attach to the debugger using the node.js client
node debug host:5858
# see where you are
debug> pause
debug> bt
From there you can poke around. You can also continue and pause again to see if you seem to consistently end up in the same code area.
Debugging a nodejs app.
V8 comes with an extensive debugger which is accessible out-of-process via a simple TCP protocol. Node has a built-in client for this debugger. To use this, start Node with the debug argument; a prompt will appear:
% node debug myscript.js
< debugger listening on port 3000
connecting... ok
break in /home/username/Code/myscript.js:1
1 x = 5;
2 setTimeout(function () {
3 debugger;
debug>
cont, c - Continue execution
next, n - Step next
step, s - Step in
out, o - Step out
pause - Pause running code
Check API for other commands reference and other details
You can also use node-inspector . Use it from any browser supporting websockets. Breakpoints, profiler, livecoding etc... It is really awesome.
Install it with
npm install -g node-inspector
then run
node-debug app.js
I run node server in console
Then in browser :8080/debug?port=5858
i see
My breakpoint doesnt work .
Help me please.
You need to run node-inspector after your app.
Also, in your case, it seems by the time you start inspector, the app will be past the section you want to debug. So try this:
# Console window 1
node --debug-brk run.js
# Console window 2
node-inspector
Then navigate to http://localhost:8080/debug?port=5858
The execution should be stopped on the first line of code. Set up your breakpoints and resume.
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