Open a new VSCode window, clone the demo repository and open it:
Inside the directory you've chosen to clone the repository, issue in a command window:
# npm install
Open the configuration/config.json file and adjust the port and database connection settings to you own environment.
In VSCode you'll see this (I opened the most important files):
Set a breakpoint in the /api/info handler:
Now start debugging from the VSCode debug tab (start the Launch QEWD Up in debug mode config option):
Now issue a call to the /api/info endpoint in your browser:
You'll see the QEWD workers starting up, the debugger will attach to them and the code stops at your breakpoint:
Now you can inspect all variables, step through your code, ...
To end your debug session, press Ctrl+C in the terminal window at the bottom where QEWD logs its messages. Don't use the debugger's stop button as it will only end your QEWD master process without properly ending the child workers!
In this case, we'll use the second debug launch configuration. First open a command window at the directory where the QEWD-Up server lives and start it in inspect mode:
# node --inspect node_modules/qewd/up/run_native
Now go to VSCode and start the Attach to QEWD Up debug config:
You'll see the debugger has attached in the command window too:
Try again to issue a call in your browser. You see QEWD-Up start its workers, the debugger attaches to them and the debugger will halt on your code breakpoint.
One thing you need to keep in mind in this debugging mode: you can't debug QEWD-Up's startup in this mode because it's already started before the debugger kicks in. When you want to debug the startup code too, use the other launch option.
A powerful feature in this mode: you can debug a remote QEWD Up server by adding the address option in launch.json. See remote debugging for this.
First, create a .vscode/launch.json file in your QEWD-Up project:
{
// Use IntelliSense to learn about possible attributes.
// Hover to view descriptions of existing attributes.
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
"version": "0.2.0",
"configurations": [
{
"type": "node",
"request": "launch",
"name": "Launch QEWD Up server in inspector mode",
"program": "${workspaceFolder}\\node_modules\\qewd\\up\\run_native",
"cwd": "${workspaceFolder}",
"autoAttachChildProcesses": true,
"console": "integratedTerminal"
},
{
"type": "node",
"protocol": "inspector",
"port": 9229,
"request": "attach",
"name": "Attach to QEWD Up server"
}
]
}This launch.json file allows you to debug your server in two ways:
- start your QEWD-Up server within VSCode using VSCode's
integratedTerminal - start your QEWD-Up server as usual in an external console window using a debug option on the commandline
In a Windows environment, there is one option that you must avoid: never use the default "console": "internalConsole" option. Because the VSCode debug console doesn't pass the Ctrl+C (SIGINT) signal to the running master process, your QEWD-Up will not stop gracefully and leave all database connections open. Using "console": "integratedTerminal" is the way to go because you get a full PowerShell command window supporting SIGINT on pressing Ctrl+C to stop the server. Also never use the debugger's red square stop button, only use Ctrl+C in the PowerShell terminal inside VSCode!
Steps:
- inside VSCode, go to the Debug tab
- start debugging using the
Launch QEWD Up server in inspector modesettings
You can debug now your QEWD-Up server completely from the very beginning, including your handler code, request/response hooks, all startup modules like addMiddleware, ...
This debugging method is not suited however on a staging (or production) environment.
Steps:
- open an external command window
- start your QEWD-Up server on the command line using:
the QEWD-Up server starts as usual but will listen for incoming debugging connections from VSCode on debug port 9229
node --inspect node_modules/qewd/up/run_native - head over to your VSCode window and go to the Debug tab
- start debugging using the
Attach to QEWD-Up serversettings
You can debug your handler code now with breakpoints, step by step, ... using all features VSCode's Node debugger provides.
This debugging method is recommended for:
- debugging handlers and/or lifecycle hook functions
- debug a staging (or even production) server
To debug QEWD-Up server startup code however, this debug option is not suited (e.g. when debugging your addMiddleWare code).
In case your server doesn't use the QEWD-Up structure already and you're using QEWD.js, you just need to change the program setting inside launch.json and point it to your own QEWD.js startup script (in most cases the modified node_modules/qewd/example/qewd.js startup file at the root folder of your QEWD.js server):
{
// Use IntelliSense to learn about possible attributes.
// Hover to view descriptions of existing attributes.
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
"version": "0.2.0",
"configurations": [
{
"type": "node",
"request": "launch",
"name": "Launch QEWD Up server in inspector mode",
"program": "${workspaceFolder}\\qewd.js",
"cwd": "${workspaceFolder}",
"autoAttachChildProcesses": true,
"console": "integratedTerminal"
},
{
"type": "node",
"protocol": "inspector",
"port": 9229,
"request": "attach",
"name": "Attach to QEWD Up server"
}
]
}