[WIP] remote-debug

jhack/main.py

@@ -57,6 +57,7 @@ def main():
     from jhack.utils.tail_charms import tail_events
     from jhack.utils.unbork_juju import unbork_juju
     from jhack.utils.unleash import vanity
+    from jhack.utils.remote_debug import remote_debug
 
     utils = typer.Typer(name="utils", help="Charming utilities.")
     utils.command(name="sync", no_args_is_help=True)(sync_deployed_charm)
@@ -70,6 +71,7 @@ def main():
     utils.command(name="fire", no_args_is_help=True)(simulate_event)
     utils.command(name="pull-cmr", no_args_is_help=True)(integrate.cmr)
     utils.command(name="print-env")(print_env)
+    utils.command(name="remote-debug", no_args_is_help=True)(remote_debug)
 
     jinx = typer.Typer(
         name="jinx",

jhack/utils/remote_debug.py

@@ -0,0 +1,120 @@
+import shlex
+import tempfile
+from pathlib import Path
+
+import typer
+
+from jhack.helpers import get_substrate, JPopen
+from jhack.logger import logger as jhack_logger
+
+logger = jhack_logger.getChild("endpoints")
+
+
+def _upload_text(text: str, target: str, remote_path: str):
+    # use a prefix that juju can 'see' despite the snap confinement!
+    with tempfile.NamedTemporaryFile(
+        dir=Path("~/.local/share/juju/").expanduser(), prefix=".jhack_tmp_"
+    ) as f:
+        Path(f.name).write_text(text)
+        # upload script to charm
+        proc = JPopen(shlex.split(f"juju scp {f.name} {target}:./{remote_path}"))
+        proc.wait()
+
+        if proc.returncode != 0:
+            exit(
+                f"failed uploading to {remote_path};"
+                f"\n stdout={proc.stdout.read()},"
+                f"\n stderr={proc.stderr.read()}"
+            )
+
+
+def _setup_remote_debug(
+    target: str, listen_address: str = "localhost:5678", debugpy_version: str = "1.8.0"
+):
+    sanitized_unit_name = target.replace("/", "-")
+    install_script_name = "install_debugpy.sh"
+
+    if get_substrate() == "k8s":
+        logger.debug("detected kubernetes env")
+
+        install_debugpy_script = f"""#!/bin/bash
+            f.name
+            cd ./agents/unit-{sanitized_unit_name}/charm/venv
+            curl -LO https://github.com/microsoft/debugpy/archive/refs/tags/v{debugpy_version}.zip
+            apt update -y
+            apt install unzip -y
+            unzip ./v{debugpy_version}.zip
+            rm ./v{debugpy_version}.zip
+            mv ./debugpy-{debugpy_version}/src/debugpy/ ./debugpy
+            """
+
+        logger.info("uploading install script...")
+        _upload_text(install_debugpy_script, target, f"./{install_script_name}")
+
+        logger.info("installing... (this may take a little while)")
+
+        # need to make it executable, else juju agent might have trouble later
+        chmod_x_proc = JPopen(
+            shlex.split(f"juju ssh {target} chmod +x ./{install_script_name}")
+        )
+        chmod_x_proc.wait()
+
+        proc = JPopen(shlex.split(f"juju ssh {target} bash ./{install_script_name}"))
+        proc.wait()
+        # proc = JPopen(shlex.split(f"juju ssh {target} ./{install_script_name}"))
+        # proc.wait()
+
+        if proc.returncode != 0:
+            exit(
+                f"failed executing install script \n stdout={proc.stdout.read()} \n stderr={proc.stderr.read()}",
+            )
+
+    else:
+        raise NotImplementedError("not implemented yet for lxd")
+
+    # let's patch dispatch!
+    logger.info("patching dispatch script... (dis-patch or dat-patch?)")
+    new_dispatch_script = """#!/bin/sh                                  
+    # Dispatch injected by jhack's remote-debug tool
+
+    JUJU_DISPATCH_PATH="${JUJU_DISPATCH_PATH:-$0}" PYTHONPATH=lib:venv:$PYTHONPATH \    
+    python3 -m debugpy --listen {listen_address} ./src/charm.py
+    """.replace(
+        "listen_address", listen_address
+    )
+
+    _upload_text(
+        new_dispatch_script,
+        target,
+        "./agents/unit-{sanitized_unit_name}/charm/dispatch",
+    )
+
+    logger.info("debugpy installed on dispatch.")
+
+
+def remote_debug(
+    target: str = typer.Argument(..., help="Juju unit name you want to target."),
+    debugpy_version: str = typer.Option(
+        "1.8.0",
+        "--debugpy-version",
+        "-d",
+        help="Debugpy version to install. See on https://github.com/microsoft/debugpy/releases "
+        "which tags are available.",
+    ),
+    listen_address: str = typer.Option(
+        "localhost:5678",
+        "--listen-address",
+        "-l",
+        help="host:port at which the debugpy server will be listening. Has to match your local "
+        "debugger client configuration.",
+    ),
+):
+    """Set up a remote debugging server (debugpy) on a juju unit.
+
+    Once this is done, you can connect an interactive debugging session from (for example) vscode.
+    """
+    _setup_remote_debug(target, listen_address, debugpy_version)
+
+
+if __name__ == "__main__":
+    _setup_remote_debug("traefik/0")