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1# gRPC Python Server Reflection
2
3This document shows how to use gRPC Server Reflection in gRPC Python.
4Please see [C++ Server Reflection Tutorial] for general information
5and more examples how to use server reflection.
6
7## Enable server reflection in Python servers
8
9gRPC Python Server Reflection is an add-on library. To use it, first install
10the [grpcio-reflection] PyPI package into your project.
11
12Note that with Python you need to manually register the service
13descriptors with the reflection service implementation when creating a server
14(this isn't necessary with e.g. C++ or Java)
15```python
16# add the following import statement to use server reflection
17from grpc_reflection.v1alpha import reflection
18# ...
19def serve():
20    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
21    helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
22    # the reflection service will be aware of "Greeter" and "ServerReflection" services.
23    SERVICE_NAMES = (
24        helloworld_pb2.DESCRIPTOR.services_by_name['Greeter'].full_name,
25        reflection.SERVICE_NAME,
26    )
27    reflection.enable_server_reflection(SERVICE_NAMES, server)
28    server.add_insecure_port('[::]:50051')
29    server.start()
30```
31
32Please see [greeter_server_with_reflection.py] in the examples directory for the full
33example, which extends the gRPC [Python `Greeter` example] on a reflection-enabled server.
34
35After starting the server, you can verify that the server reflection
36is working properly by using the [`grpc_cli` command line tool]:
37
38 ```sh
39  $ grpc_cli ls localhost:50051
40  ```
41
42  output:
43  ```sh
44  grpc.reflection.v1alpha.ServerReflection
45  helloworld.Greeter
46  ```
47
48  For more examples and instructions how to use the `grpc_cli` tool,
49  please refer to the [`grpc_cli` documentation] and the
50  [C++ Server Reflection Tutorial].
51
52## Additional Resources
53
54The [Server Reflection Protocol] provides detailed
55information about how the server reflection works and describes the server reflection
56protocol in detail.
57
58
59[C++ Server Reflection Tutorial]: ../server_reflection_tutorial.md
60[grpcio-reflection]: https://pypi.org/project/grpcio-reflection/
61[greeter_server_with_reflection.py]: https://github.com/grpc/grpc/blob/master/examples/python/helloworld/greeter_server_with_reflection.py
62[Python `Greeter` example]: https://github.com/grpc/grpc/tree/master/examples/python/helloworld
63[`grpc_cli` command line tool]: https://github.com/grpc/grpc/blob/master/doc/command_line_tool.md
64[`grpc_cli` documentation]: ../command_line_tool.md
65[C++ Server Reflection Tutorial]: ../server_reflection_tutorial.md
66[Server Reflection Protocol]: ../server-reflection.md
67