Typically, I use node inspector (https://github.com/node-inspector/node-inspector) to debug node.js. Can this be used to attach to a remote node.js instance running in the JVM via J2V8?
Also, it looks like the dev version of node.js supports native Chrome debugging: https://github.com/nodejs/node/pull/6792. If J2V8 adopts this version of node.js, will I be able to simply attach the Chrome debugger directly to the JVM?
If the question is still relevant - I have created j2v8-debugger library.
It allows debugging J2V8 using Chrome DevTools.
Basic features like setting/removing breakpoints, step into, step out and step over, variables inspection, etc. are implemented.
It uses Stetho lib for communication with Chrome DevTools.
Also it's uses DebugHandler for accessing V8 debug information.
If you need need to debug J2V8, which runs on non-Android JVM you would need to use another lib for communication to Chrome DevTools, but likely you could re-use all the logic from this project as it's basically POJO/JSON, which are send over web socket.
Hope it could be helpful.
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I am developer with poor experience, however with strong academic CS background.
So please be patient where I am wrong somewhere.
As far I know, typescript can be executed on JS server and it works in this way in my case. Namely, I execute e2e tests with protactor (angular test framework).
I would like to debug it and check what methods was called during such execution on nodejs. To give you more details, I would like if (and possibly parameters) was invoked
waitForAngular(rootSelector, callback) method.
I know that it is possible to dump a variety of traces and debugging info from JVM, however I have no idea how can I do it with nodejs in my specific case.
Could you help me, please?
Around where you have your calls to waitForAngular (or any other code that you want to check), add a console.trace(), which will display a stack trace at that exact line of code.
You can read more about console.trace() and other console API methods at this document by the Chrome project (node.js uses the JS engine that Chrome uses): https://developers.google.com/web/tools/chrome-devtools/console/api#trace
You can sprinkle debugger statements in your code to stop execution which will allow you to step through your code. Similarly, you could start your Node process with the --inspect-brk argument to use Chrome DevTools to step through your code.
Is is possible to debug a wasm module through node?
I am using vscode and compiling with emcc -g4 --source-map-base. Putting a breakpoint in the C source file is ineffective. Trying to debug with node inspector node --inspect through Chrome doesn't allow me to use breakpoints either, although it is possible to debug wasm modules from regular web pages in Chrome.
I am using nodejs v10.13.
WebAssembly Source Maps is supported by both Firefox Developer Edition (in screenshot) and Chrome 71.
What you forgot is, to include a path to the source map. For example:
emcc -g4 --source-map-base http://localhost:8000/
Every source files path is prefixed with http://localhost:8000/ with this option. So replace this with your source directory.
So, I managed to get something working. I installed:
Node v11.4
Chrome beta 71 (because of this)
And launched the node process with node --inspect, for attaching the Chrome DevTools.
Moreover, in my code, instead of doing WebAssembly.instantiate in one shot (supplying directly the bitcode), I do it in two steps: WebAssembly.compile first, and then WebAssembly.instantiate. As soon as compile gets executed, there are some "wasm" sources being made available in the DevTools. This is the WebAssembly in wast text form, in which breakpoints can be set before it gets executed by instantiate.
But you can't debug from the original C-source files, Chrome DevTools only shows the decompiled wast yet. This feels like the stone age of debugging, but it is still possible to debug.
Edit 2020: This article https://developers.google.com/web/updates/2019/12/webassembly seems to indicate you should now be able to debug in devtools, from the original C source files. I did not try it, though.
I am having difficulty resolving the electron modules in my web application using Electron v0.32.3 using require. My understanding (although its not very clear in the docs) is that the modules are supposed to be automatically available to require of the application being run in the webview (examples include 'ipc' and 'remote'). I can see that they are there at runtime, but I am not sure how to access them:
I feel like there is some piece to this that I am missing. Other information: my web application is a Durandal 2x SPA that uses require to load modules already. Is there any other kind of setup that is required in the render process requirejs config to access these modules?
It turns out I just didn't understand all of the different processes going on. So with an application that is using a webview inside of a browser-window, there are actually three processes to be concerned about:
Main process - has access to node
Renderer process (browser window) - has access to node by default
Web view process - does not have access to node by default
I was seeing the node modules available to 2) and trying to use them in 3). The webview has the 'nodeintegration' attribute that can be used to enable this:
http://electron.atom.io/docs/v0.34.0/api/web-view-tag/#nodeintegration
However, using a preload script allows for exposing only the necessary node functionality with using nodeintegration:
http://electron.atom.io/docs/v0.34.0/api/web-view-tag/#preload
I went with that solution, setting up communication between the renderer process and the webview process.
I am running an example application that uses native messaging on OS X.
After downloading an example of chrome, I registered an extension and located a native messaging host file at /Library/Google/Chrome/NativeMessagingHosts/com.google.chrome.example.echo.json.
According to the guide, Chrome starts a native messaging host in a separate process.
But I cannot look for that process.
Is there a way for chrome to run host process?
What do I miss?
The sample app provided by Chrome is a packaged app. Once you install it you have to launch it from your browser. And then do ps ax and look for the sample python-script process.
To run the app, start chrome and go to the following URL:
chrome-extension://knldjmfmopnpolahpmmgbagdohdnhkik/main.html
If you've done everything right, it should start the python script and you should see a window.
if its not working, have a look at chrome's console. you could also enable additional chrome logs - see here: http://www.chromium.org/for-testers/enable-logging
I have been seeking solutions for debugging Node.js based web application from days. I had tried to debug with Eclipse + Chrome debugger plugin but failed, I posted the error in this session 'Failed to get tabs for debugging' when trying to debug NodeJs with chrome debugger for Eclipse, but could not find an answer.
However, as Node.js is so popular, I have no doubt that a lot developers have the solution for debugging Node.js server JavaScript code. I appretiate if you could share me your solution of setting up an IDE (edit and debug) for Node.js server JavaScript code, or at least how to debug it.
I would suggest using node-inspector. Here is a good tutorial for setting it up. It allows you to use a browser tab to look at your code, set breakpoints, and step through it. Additionally, you can start node with the flag --debug-brk and it will insert a break point on the first line, if you need to debug something that happens on startup.
There are several tools to debug a node application. A great ressource has been postet on Github recently.
A simple debugging setup might be just adding a breakpoint to your code and start node in debug mode like this:
Example code with use of debugger, a manual breakpoint.
app.get('/foo', function(req, res) {
var something = 123;
debugger; // execution stops if this point is reached
foo(something);
});
Start node in debug mode:
$ node debug app.js
Once you started the application in debug mode you use the application (e.g., navigate to the ressource with your browser) and once a breakpoint occurs, the execution stops and you have a debugger environment in your terminal.
Try to use Weinre (WEb INspector REmote). It's a node app help you debug UI, log for web app on devices.
It hope it can help you.