[Core]Add runtime context for python worker (#10309)

* add runtime context for python

* fixed

* code fixed

* test added

* lint

* lint

python/ray/tests/test_runtime_context.py

@@ -0,0 +1,76 @@
+import ray
+import os
+import signal
+import time
+import sys
+
+
+def test_was_current_actor_reconstructed():
+    ray.init()
+
+    @ray.remote(max_restarts=10)
+    class A(object):
+        def __init__(self):
+            self._was_reconstructed = ray.get_runtime_context(
+            ).was_current_actor_reconstructed
+
+        def get_was_reconstructed(self):
+            return self._was_reconstructed
+
+        def update_was_reconstructed(self):
+            return ray.get_runtime_context().was_current_actor_reconstructed
+
+        def get_pid(self):
+            return os.getpid()
+
+        # The following methods is to apply the checkpointable interface.
+        def should_checkpoint(self, checkpoint_context):
+            return False
+
+        def save_checkpoint(self, actor_id, checkpoint_id):
+            pass
+
+        def load_checkpoint(self, actor_id, available_checkpoints):
+            pass
+
+        def checkpoint_expired(self, actor_id, checkpoint_id):
+            pass
+
+    a = A.remote()
+    # `was_reconstructed` should be False when it's called in actor.
+    assert ray.get(a.get_was_reconstructed.remote()) is False
+    # `was_reconstructed` should be False when it's called in a remote method
+    # and the actor never fails.
+    assert ray.get(a.update_was_reconstructed.remote()) is False
+
+    pid = ray.get(a.get_pid.remote())
+    os.kill(pid, signal.SIGKILL)
+    time.sleep(2)
+    # These 2 methods should be return True because
+    # this actor failed and restored.
+    assert ray.get(a.get_was_reconstructed.remote()) is True
+    assert ray.get(a.update_was_reconstructed.remote()) is True
+
+    ray.shutdown()
+
+
+def test_runtime_context_interface():
+    ray.init()
+
+    @ray.remote(max_restarts=10)
+    class A(object):
+        def current_job_id(self):
+            return ray.get_runtime_context().current_job_id
+
+        def current_actor_id(self):
+            return ray.get_runtime_context().current_actor_id
+
+    a = A.remote()
+    assert ray.get(a.current_job_id.remote()) is not None
+    assert ray.get(a.current_actor_id.remote()) is not None
+    ray.shutdown()
+
+
+if __name__ == "__main__":
+    import pytest
+    sys.exit(pytest.main(["-v", __file__]))