How to debug a Singer Tap using VS Code

Question

In creating new Singer Taps using the Meltano SDK, it's not always clear how to setup testing in VS Code.

What's the best way to get the VS Code test features working?

Answer 1

First Method: Unit testing with VS Code "Tests" pane

This method makes unit tests (pytest tests) easy to run in the VS Code "Tests" pane.

Prereqs:

• Python is installed on your machine.
• The Python VS Code extension is installed.
• You've run poetry install at least once.
• You've set the Python interpreter to the Poetry environment via: "Command Palette" > "Python: Select Interpreter" and then select the matching Poetry environment.

Once the above are complete, the "tests" pane should populate with the list of unit tests and you'll have an option in the VS Code GUI to "Run" or "Debug" each test.

Second Method: Integration test by actually invoking the tap

This method actually runs your tap and sends the output to target-json or a similar sample target.

Prereqs:

• Add a main to the bottom of your tap.py to make it invocable:

  if __name__ == "__main__":
    TapGoogleAnalytics.cli()
  

• Install target-jsonl via pipx install target-jsonl or similar.

Replace tap_foobar with the actual name of your tap's library and then paste this into VS Code's launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Python: Current File",
            "type": "python",
            "request": "launch",
            "program": "${workspaceRoot}/tap_foobar/tap.py",
            "console": "integratedTerminal",
            "args": ["--config", ".secrets/config.json", "|", "target-jsonl"],
            "env": { "PYTHONPATH": "${workspaceRoot}"}
        }
    ]
}