Breakpoints

[inancgumus]

This PR contains experimental features to debug a k6-browser script.

Breakpoint client

This PR adds the ability to pause script execution from the given breakpoints and resume them.

The client pauses the script execution when a breakpoint is hit.

Protocol

command	explanation
get_breakpoints	Client initially requests the breakpoints from the server.
update_breakpoints	Client continuously listens for new breakpoints from the server.
resume	Server can resume the script execution.

get_breakpoints

The client waits for the server to send an initial set of breakpoints before continuing. The reason for "handshaking" an initial breakpoint is to pause the script execution until the server responds with something. Otherwise, the script would immediately continue.

Client

{
    "command": "get_breakpoints"
}

Server

[
    {
        "file": "file:///Users/inanc/grafana/k6browser/main/examples/fillform.js",
        "line": 28
    }
]

update_breakpoints

Server

{
    "command": "update_breakpoints",
    "data": [
        {
            "file": "file:///Users/inanc/grafana/k6browser/main/examples/fillform.js",
            "line": 30
        }
    ]
}

resume

Server

{
    "command": "resume"
}

Activate the client

K6_BROWSER_BREAKPOINT_SERVER_URL=ws://localhost:8080/breakpoint k6 run script.js

Open a DevTools window

For convenience, users may open a DevTools window.

K6_BROWSER_DEBUG=1 k6 ...