Support {:all, endpoint} in :services to auto-discover

README.md

@@ -47,14 +47,15 @@ This is written and tested using [grpcurl](https://github.com/fullstorydev/grpcu
   end
   ```
   or both as desired.  `version` is the grpc reflection spec, which can be `v1` or `v1alpha`.  `services` is the services that will be exposed by that server by reflection.  You can expose a service through both services if desired.
-1. Add the reflection supervisor to your supervision tree to host the cached reflection state
+  Instead of using an explicit list of services, you may alternatively use `{:all, MyApp.GrpcEndpoint}`, to include all services from an endpoint. This is a more succint alternative if you want to expose reflection for all services in your endpoint. On the other hand, you lose the fine-grained control of the ehaustive list.
+3. Add the reflection supervisor to your supervision tree to host the cached reflection state
 ```elixir
 children = [
   ...other children,
   GrpcReflection
 ]
 ```
-1. Add your servers to your grpc endpoint
+4. Add your servers to your grpc endpoint
 
 ## interacting with your reflection server
 
@@ -82,7 +83,7 @@ message HelloReply {
 $ grpcurl -plaintext -format text -d 'name: "faker"' localhost:50051 helloworld.Greeter.SayHello
 message: "Hello faker"
 today: <
-  seconds:1708412184 nanos:671267628 
+  seconds:1708412184 nanos:671267628
 >
 ```
 

lib/grpc_reflection.ex

@@ -11,15 +11,15 @@ defmodule GrpcReflection do
   defmodule Helloworld.Reflection.Server do
     use GrpcReflection.Server,
       version: :v1,
-      services: [Helloworld.Greeter.Service]
+      services: [Helloworld.Greeter.Service] # alternatively, `{:all, HelloWorld.Endpoint}` can be used to include all services from the endpoint.
   end
   ```
 
   2. Add the reflection supervisor to your supervision tree
   ```elixir
   children = [
+    GrpcReflection,
     {GRPC.Server.Supervisor, endpoint: Helloworld.Endpoint, port: 50051, start_server: true},
-    GrpcReflection
   ]
   ```
 

lib/grpc_reflection/service/agent.ex

@@ -14,6 +14,12 @@ defmodule GrpcReflection.Service.Agent do
     name = Keyword.get(opts, :name)
     services = Keyword.get(opts, :services)
 
+    services =
+      case services do
+        {:all, endpoint} -> endpoint_services(endpoint)
+        list -> list
+      end
+
     case Builder.build_reflection_tree(services) do
       {:ok, state} ->
         Agent.start_link(fn -> state end, name: name)
@@ -24,6 +30,12 @@ defmodule GrpcReflection.Service.Agent do
     end
   end
 
+  defp endpoint_services(endpoint) do
+    :servers
+    |> endpoint.__meta__()
+    |> Enum.map(fn server -> server.__meta__(:service) end)
+  end
+
   @spec list_services(cfg_t()) :: list(binary)
   def list_services(cfg) do
     name = start_agent_on_first_call(cfg)

test/grpc_reflection_test.exs

@@ -4,7 +4,7 @@
   use GrpcCase
 
   defmodule Service do
     use GrpcReflection.Server, version: :v1
   end
 
   test "adding a service changes responses" do
@@ -68,4 +68,19 @@
                Service.get_by_filename("helloworld.HelloRequest.proto")
     end
   end
+
+  test "server reading services from endpoint" do
+    defmodule AutoServiceDiscoveryServer do
+      use GrpcReflection.Server,
+        version: :v1,
+        services: {:all, GrpcReflection.TestEndpoint.Endpoint}
+    end
+
+    assert AutoServiceDiscoveryServer.list_services() ==
+             [
+               "grpc.reflection.v1alpha.ServerReflection",
+               "grpc.reflection.v1.ServerReflection",
+               "helloworld.Greeter"
+             ]
+  end
 end