GRPC Server: Add README (#87442)

pkg/services/grpcserver/README.md

@@ -0,0 +1,41 @@
+# grpcserver
+
+The `grpcserver` package provides the implementation of the gRPC server for handling remote procedure calls in Grafana. It enables communication between clients and the Grafana server using the gRPC protocol.
+
+## Structure
+
+- `service.go`: This file contains the main configuration of the gRPC service, which implements the `registry.BackgroundService` interface.
+- `interceptors`: This folder contains the middleware functions used for intercepting and modifying gRPC requests and responses.
+- `context`: This folder contains helpers related to getting and setting values in `context.Context`.
+- `health.go`: This provides the implementation of the gRPC health check service, which is automatically registered with the gRPC server.
+- `reflection.go`: This provides the implementation of the gRPC reflection service, which is automatically registered with the gRPC server.
+
+## Usage
+
+Enable the gRPC server in Grafana by setting the `grpcServer` feature toggle to `true` in your `custom.ini` configuration file. 
+
+``` ini
+[feature_toggles]
+grpcServer = true
+```
+
+You can specify the gRPC server specific settings in the `grpc_server` section of the configuration file.
+
+``` ini
+[grpc_server]
+network = "tcp"
+address = "127.0.0.1:10000"
+use_tls = false
+cert_file =
+key_file =
+# this will log the request and response for each unary gRPC call
+enable_logging = false
+# Maximum size of a message that can be received in bytes. If not set, uses the gRPC default (4MiB).
+max_recv_msg_size =
+# Maximum size of a message that can be sent in bytes. If not set, uses the gRPC default (unlimited).
+max_send_msg_size =
+```
+
+## Example Services
+
+View [health.go] and [reflection.go] for examples of how to implement gRPC services in Grafana. These services are currently initialized by the [background service registry](../../registry/backgroundsvcs/background_services.go).