Cannot debug serverless application in Visual Studio Code

Question

I have tried to debug serverless application developed using serverless framework in VS code. I have followed this article.

But when I trying to debug the code I\'m

Answer 1

Update for 2020:

Do what the other guides state and setup your project with a launch.json file.

The problem I had was that the supposed file "program": "${workspaceRoot}/node_modules/.bin/sls" threw an error.

I changed it to "${workspaceRoot}/node_modules/serverless/bin/serverless" and it worked. Here's the full file:

.vscode/launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Serverless debug",
            "program": "${workspaceRoot}/node_modules/serverless/bin/serverless",
            "args": [
                "invoke",
                "local",
                "-f",
                "hello",
                "--data",
                "{}"
            ]
        }
    ]
}

Be aware that the argument hello is the name of the function I want to debug. I think the intended use case must be that you change that file name for whatever function you want to invoke. Maybe someone could create a VSCode plugin to do this?

Answer 2

To get debugging to work with TypeScript I needed to add outFiles set to the folder where my compiled code goes.

"outFiles": [
    "${workspaceRoot}/dist/**/*.js"
]

I haven't tried to debug straight JS but I would assume it's something like this.

"outFiles": [
    "${workspaceRoot}/**/*.js"
]

Answer 3

I attempted to follow the same article, and experienced the same error. Adding outFiles didn't help, although it did change my error message to:

Cannot launch program 'd:\<path>\node_modules\.bin\sls' because corresponding JavaScript cannot be found.

---

I can't explain why VSCode has a problem with the executable in node_modules/.bin, but if I point at node_modules/serverless/bin instead, things work as expected:

"program": "${workspaceFolder}\\node_modules\\serverless\\bin\\serverless",

---

Here is my full working configuration, where my test event JSON exists in sample-event.json in the project root:

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Debug Lambda",
            "program": "${workspaceFolder}/node_modules/serverless/bin/serverless",
            "args": [
                "invoke",
                "local",
                "-f",
                "<function-name>",
                "--data",
                "{}" // You can use this argument to pass data to the function to help with the debug
            ]
        }
    ]
}

---

Using Serverless ^1.26.1, Node 8.9.4 LTS, VSCode 1.20.1

Answer 4

None of the solutions worked for me so here is my modification as a resource. Also, multiple coworkers were able to attack just by flipping auto-attach to on and using the invoke local keywords.

Below is a snippet featuring the launch.json that eventually worked for me. /w comments for clarity where my function is named Processor.

--function or -f The name of the function in your service that you want to invoke locally.

--path or -p The path to a json file holding input data to be passed to the invoked function as the event. This path is relative to the root directory of the service.

--stage or -s The stage in your service you want to invoke your function in.

• "serverless": "^1.30.3"
• "serverless-plugin-typescript": "^1.1.5",
• node: 8.10.0

• npm: 5.6.0

  {
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Debug Lambda",
            "program": "${workspaceFolder}/node_modules/.bin/sls",
            "args": [
                "invoke",
                "local",
                "-f",
                "Processor",
                "-p",
                "./events/S3toLambda.json",
                "-s",
                "local"
            ],
            "autoAttachChildProcesses": true
        }
    ]
  }