[Debugger] Adding debupgy as the ray debugger (#42311) (#42361)

- enabled debugpy as the ray debugger for breakpoint and post_mortem debugging
- added flag RAY_DEBUG=1 to enable debugpy. If RAY_DEBUG is not set and RAY_PDB is set, then rpdb will be used.
- used state api to save worker debugging port.

python/ray/util/__init__.py

@@ -6,6 +6,7 @@
 from ray._private.services import get_node_ip_address
 from ray.util import iter
 from ray.util import rpdb as pdb
+from ray.util import debugpy as ray_debugpy
 from ray.util.actor_pool import ActorPool
 from ray.util import accelerators
 from ray.util.annotations import PublicAPI
@@ -62,6 +63,7 @@ def list_named_actors(all_namespaces: bool = False) -> List[str]:
     "get_current_placement_group",
     "get_node_ip_address",
     "remove_placement_group",
+    "ray_debugpy",
     "inspect_serializability",
     "collective",
     "connect",

python/ray/util/debugpy.py

@@ -0,0 +1,131 @@
+import logging
+import os
+import sys
+import threading
+import importlib
+
+import ray
+from ray.util.annotations import DeveloperAPI
+
+log = logging.getLogger(__name__)
+
+POST_MORTEM_ERROR_UUID = "post_mortem_error_uuid"
+
+
+def _try_import_debugpy():
+    try:
+        debugpy = importlib.import_module("debugpy")
+        if not hasattr(debugpy, "__version__") or debugpy.__version__ < "1.8.0":
+            raise ImportError()
+        return debugpy
+    except (ModuleNotFoundError, ImportError):
+        log.error(
+            "Module 'debugpy>=1.8.0' cannot be loaded. "
+            "Ray Debugpy Debugger will not work without 'debugpy>=1.8.0' installed. "
+            "Install this module using 'pip install debugpy==1.8.0' "
+        )
+        return None
+
+
+# A lock to ensure that only one thread can open the debugger port.
+debugger_port_lock = threading.Lock()
+
+
+def _override_breakpoint_hooks():
+    """
+    This method overrides the breakpoint() function to set_trace()
+    so that other threads can reuse the same setup logic.
+    This is based on: https://github.com/microsoft/debugpy/blob/ef9a67fe150179ee4df9997f9273723c26687fab/src/debugpy/_vendored/pydevd/pydev_sitecustomize/sitecustomize.py#L87 # noqa: E501
+    """
+    sys.__breakpointhook__ = set_trace
+    sys.breakpointhook = set_trace
+    import builtins as __builtin__
+
+    __builtin__.breakpoint = set_trace
+
+
+def _ensure_debugger_port_open_thread_safe():
+    """
+    This is a thread safe method that ensure that the debugger port
+    is open, and if not, open it.
+    """
+
+    # The lock is acquired before checking the debugger port so only
+    # one thread can open the debugger port.
+    with debugger_port_lock:
+        debugpy = _try_import_debugpy()
+        if not debugpy:
+            return
+
+        debugger_port = ray._private.worker.global_worker.debugger_port
+        if not debugger_port:
+            (host, port) = debugpy.listen(
+                (ray._private.worker.global_worker.node_ip_address, 0)
+            )
+            ray._private.worker.global_worker.set_debugger_port(port)
+            log.info(f"Ray debugger is listening on {host}:{port}")
+        else:
+            log.info(f"Ray debugger is already open on {debugger_port}")
+
+
+@DeveloperAPI
+def set_trace(breakpoint_uuid=None):
+    """Interrupt the flow of the program and drop into the Ray debugger.
+    Can be used within a Ray task or actor.
+    """
+    debugpy = _try_import_debugpy()
+    if not debugpy:
+        return
+
+    _ensure_debugger_port_open_thread_safe()
+
+    # debugpy overrides the breakpoint() function, so we need to set it back
+    # so other threads can reuse it.
+    _override_breakpoint_hooks()
+
+    with ray._private.worker.global_worker.worker_paused_by_debugger():
+        log.info("Waiting for debugger to attach...")
+        debugpy.wait_for_client()
+
+    log.info("Debugger client is connected")
+    if breakpoint_uuid == POST_MORTEM_ERROR_UUID:
+        _debugpy_excepthook()
+    else:
+        _debugpy_breakpoint()
+
+
+def _debugpy_breakpoint():
+    """
+    Drop the user into the debugger on a breakpoint.
+    """
+    import pydevd
+
+    pydevd.settrace(stop_at_frame=sys._getframe().f_back)
+
+
+def _debugpy_excepthook():
+    """
+    Drop the user into the debugger on an unhandled exception.
+    """
+    import threading
+
+    import pydevd
+
+    py_db = pydevd.get_global_debugger()
+    thread = threading.current_thread()
+    additional_info = py_db.set_additional_thread_info(thread)
+    additional_info.is_tracing += 1
+    try:
+        error = sys.exc_info()
+        py_db.stop_on_unhandled_exception(py_db, thread, additional_info, error)
+        sys.excepthook(error[0], error[1], error[2])
+    finally:
+        additional_info.is_tracing -= 1
+
+
+def _is_ray_debugger_enabled():
+    return "RAY_DEBUG" in os.environ
+
+
+def _post_mortem():
+    return set_trace(POST_MORTEM_ERROR_UUID)

python/ray/util/rpdb.py

@@ -280,6 +280,9 @@ def set_trace(breakpoint_uuid=None):
 
     Can be used within a Ray task or actor.
     """
+    if ray.util.ray_debugpy._is_ray_debugger_enabled():
+        return ray.util.ray_debugpy.set_trace(breakpoint_uuid)
+
     # If there is an active debugger already, we do not want to
     # start another one, so "set_trace" is just a no-op in that case.
     if ray._private.worker.global_worker.debugger_breakpoint == b"":
@@ -301,6 +304,9 @@ def _driver_set_trace():
     This disables Ray driver logs temporarily so that the PDB console is not
     spammed: https://github.com/ray-project/ray/issues/18172
     """
+    if ray.util.ray_debugpy._is_ray_debugger_enabled():
+        return ray.util.ray_debugpy.set_trace()
+
     print("*** Temporarily disabling Ray worker logs ***")
     ray._private.worker._worker_logs_enabled = False
 
@@ -314,10 +320,13 @@ def enable_logging():
 
 
 def _is_ray_debugger_enabled():
-    return "RAY_PDB" in os.environ
+    return "RAY_PDB" in os.environ or ray.util.ray_debugpy._is_ray_debugger_enabled()
 
 
 def _post_mortem():
+    if ray.util.ray_debugpy._is_ray_debugger_enabled():
+        return ray.util.ray_debugpy._post_mortem()
+
     rdb = _connect_ray_pdb(
         host=None,
         port=None,