Debugging

Vonage Cloud Runtime allows you to debug your code locally as if it was deployed on the platform. It works by starting a remote debug server that proxies requests to your local version. You can use your IDE to attach a debugger, set breakpoints and run through the execution of your project line by line.

Debugger Dependencies

You will need to install a file watcher, for example, nodemon globally:

Start a Debug Session using the Terminal

Edit your configuration file (vcr.yml) to add an entrypoint for debug under a root level debug:

Next, open a terminal session in your project directory and run the debug start command:

This will start the server, so once it is done you can start using your application. The debugger will show any incoming and outgoing requests. Code changes you make and save will trigger the debugger to reload automatically.

Injected Environment Variables

When you run your project using vcr debug (or deploy your project to Cloud Runtime), the platform will inject some environment variables for you along with the environment object from your configuration file.

Debug from VSCode

Using VSCode you can attach a debugger to the server to allow you to set breakpoints and step through your code. To do so click on the Run and Debug button, then create a launch.json file. Select nodejs as a preset:

In the launch.json file replace the entire contents of the file with the following:

This will start your application using the npm run debug command and attach the VSCode debugger. Your npm run debug command should run vcr debug.

Click on the start debugging button:

Once your application is running and the debugger is attached you will have access to the debug controls.

Breakpoints

By clicking to the left of a line number you can set a breakpoint in your code, so the program will pause on this line and allow you to inspect the program, step over and so on:

When your breakpoint is hit, VSCode will highlight the line that it has stopped on, and using the debug console you can print out values from your program:

Alternatively, you can use the debug controls to inspect your code even deeper by stepping in and out of functions or continuing past the current line.