OkGRPC

gRPC Java client and CLI based on gRPC Server Reflection. Can be used to inspect gRPC services and execute RPC methods dynamically without needing a proto file. The client can be directly used from any JVM source code, while the CLI can be executed on command line. No installation necessary, only needs Java 8 or later.

CLI Usage

You can find the latest version on Bintray.

It's also on jcenter.

It's an executable JAR. Run with --help for main CLI usage, and <command> --help for specific command usage.

For brevity, I show java -jar okgrpc-cli-<version>.jar simply as okgrpc-cli below.

Get all services:

$ okgrpc-cli -a localhost:64575 get
com.asarkar.okgrpc.test.GreetingService
grpc.reflection.v1alpha.ServerReflection

Describe a service:

$ okgrpc-cli -a localhost:64575 desc -s com.asarkar.okgrpc.test.GreetingService
name: "com/asarkar/okgrpc/test/greeting_service.proto"
package: "com.asarkar.okgrpc.test"
dependency: "com/asarkar/okgrpc/test/greeting.proto"
service {
  name: "GreetingService"
  method {
    name: "Greet"
    input_type: ".com.asarkar.okgrpc.test.GreetRequest"
    output_type: ".com.asarkar.okgrpc.test.GreetResponse"
    options {
    }
  }
  // more methods elided
}

Describe a method:

$ okgrpc-cli -a localhost:64575 desc -m com.asarkar.okgrpc.test.GreetingService.Greet
name: "Greet"
input_type: ".com.asarkar.okgrpc.test.GreetRequest"
output_type: ".com.asarkar.okgrpc.test.GreetResponse"
options {
}

Describe a type:

$ okgrpc-cli -a localhost:64575 desc -t com.asarkar.okgrpc.test.GreetRequest
name: "GreetRequest"
field {
  name: "greeting"
  number: 1
  label: LABEL_OPTIONAL
  type: TYPE_MESSAGE
  type_name: ".com.asarkar.okgrpc.test.Greeting"
}

Execute a method:

$ okgrpc-cli -a localhost:64575 exec \
  > -h "key: value" \
  > com.asarkar.okgrpc.test.GreetingService.Greet \
  > '{ "greeting": { "name" : "test" } }'
{
  "result": "Hello, test"
}

It is perfectly fine to send multiple requests for client streaming calls; each string needs to be a valid JSON representing the Protobuf request object.

Binary data may be sent in the request as valid UTF-8 encoded string (like Base64). Of course, the server needs to know that and decode accordingly.

It is possible to use local .proto files if reflection isn't enabled on the server.

$ okgrpc-cli -a localhost:64575 exec \
  > --proto-path=<directory in which to search for proto file imports> \
  > --proto-file=<service proto file relative to the proto paths> \
  > com.asarkar.okgrpc.test.GreetingService.Greet \
  > '{ "greeting": { "name" : "test" } }'
{
  "result": "Hello, test"
}

Client Usage

You can find the latest version on Bintray.

It's also on jcenter.

val client = OkGrpcClient.Builder()
    .withChannel(ManagedChannelFactory.getInstance(address))
    .build()

All the methods are defined as extension functions in the OkGrpcClientExtn file, that from Java, will become static methods in OkGrpcClientExtnKt class.

See KDoc for more details.

Contribute

This project is a volunteer effort. You are welcome to send pull requests, ask questions, or create issues. If you like it, you can help by spreading the word!

License

Copyright 2020 Abhijit Sarkar - Released under Apache License v2.0.