[Placement Group]Add get all placement group api (#11460)

* add get all interface for placement group

* add get all interface for placement group

* make it work

* fix lint

* fix lint

* fix comment

* add cpp test

* fix python lint

python/ray/includes/global_state_accessor.pxd

@@ -31,3 +31,4 @@ cdef extern from "ray/gcs/gcs_client/global_state_accessor.h" nogil:
         c_bool AddWorkerInfo(const c_string &serialized_string)
         unique_ptr[c_string] GetPlacementGroupInfo(
             const CPlacementGroupID &placement_group_id)
+        c_vector[c_string] GetAllPlacementGroupInfo()

python/ray/includes/global_state_accessor.pxi

@@ -122,6 +122,12 @@ cdef class GlobalStateAccessor:
             result = self.inner.get().AddWorkerInfo(cserialized_string)
         return result
 
+    def get_placement_group_table(self):
+        cdef c_vector[c_string] result
+        with nogil:
+            result = self.inner.get().GetAllPlacementGroupInfo()
+        return result
+
     def get_placement_group_info(self, placement_group_id):
         cdef unique_ptr[c_string] result
         cdef CPlacementGroupID cplacement_group_id = (

python/ray/state.py

@@ -388,8 +388,18 @@ class GlobalState:
                                         FromString(placement_group_info))
                 return self._gen_placement_group_info(placement_group_info)
         else:
-            raise NotImplementedError(
-                "Get all placement group is not implemented yet.")
+            placement_group_table = self.global_state_accessor.\
+                                    get_placement_group_table()
+            results = {}
+            for placement_group_info in placement_group_table:
+                placement_group_table_data = gcs_utils.\
+                    PlacementGroupTableData.FromString(placement_group_info)
+                placement_group_id = binary_to_hex(
+                    placement_group_table_data.placement_group_id)
+                results[placement_group_id] = \
+                    self._gen_placement_group_info(placement_group_table_data)
+
+            return results
 
     def _gen_placement_group_info(self, placement_group_info):
         # This should be imported here, otherwise, it will error doc build.

python/ray/tests/test_placement_group.py

@@ -406,6 +406,7 @@ def test_placement_group_table(ray_start_cluster):
 
     # Now the placement group should be scheduled.
     cluster.add_node(num_cpus=5, num_gpus=1)
+
     cluster.wait_for_nodes()
     actor_1 = Actor.options(
         placement_group=placement_group,
@@ -415,6 +416,28 @@ def test_placement_group_table(ray_start_cluster):
     result = ray.util.placement_group_table(placement_group)
     assert result["state"] == "CREATED"
 
+    # Add tow more placement group for placement group table test.
+    second_strategy = "SPREAD"
+    ray.util.placement_group(
+        name="second_placement_group",
+        strategy=second_strategy,
+        bundles=bundles)
+    ray.util.placement_group(
+        name="third_placement_group",
+        strategy=second_strategy,
+        bundles=bundles)
+
+    placement_group_table = ray.util.placement_group_table()
+    assert len(placement_group_table) == 3
+
+    true_name_set = {"name", "second_placement_group", "third_placement_group"}
+    get_name_set = set()
+
+    for _, placement_group_data in placement_group_table.items():
+        get_name_set.add(placement_group_data["name"])
+
+    assert true_name_set == get_name_set
+
 
 def test_cuda_visible_devices(ray_start_cluster):
     @ray.remote(num_gpus=1)

python/ray/util/placement_group.py

@@ -185,17 +185,18 @@ def remove_placement_group(placement_group: PlacementGroup):
     worker.core_worker.remove_placement_group(placement_group.id)
 
 
-def placement_group_table(placement_group: PlacementGroup) -> dict:
+def placement_group_table(placement_group: PlacementGroup = None) -> list:
     """Get the state of the placement group from GCS.
 
     Args:
         placement_group (PlacementGroup): placement group to see
             states.
     """
-    assert placement_group is not None
     worker = ray.worker.global_worker
     worker.check_connected()
-    return ray.state.state.placement_group_table(placement_group.id)
+    placement_group_id = placement_group.id if (placement_group is
+                                                not None) else None
+    return ray.state.state.placement_group_table(placement_group_id)
 
 
 def get_current_placement_group() -> Optional[PlacementGroup]: