Generate protobuf definition bal files using Syntax tree

[madhukaw]

Create a new Protocol Buffers definition file grpc_unary_blocking.proto and add the below service definition.

syntax = "proto3";
import "google/protobuf/wrappers.proto";
service HelloWorld {
	rpc hello (google.protobuf.StringValue)
			returns (google.protobuf.StringValue);
}

Run the command below in Ballerina tools distribution for stub generation.

ballerina grpc --input grpc_unary_blocking.proto  --output stubs

Actual output:

Downloading protoc executor file - protoc-3.9.1-osx-x86_64.exe
Download successfully completed. Executor file path - /var/folders/p8/hxg5f9kd2bj8svp8v12m9tj40000gn/T/protoc-3.9.1-osx-x86_64.exe
Successfully extracted library files.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.github.jknack.handlebars.context.MemberValueResolver (file:/Library/Ballerina/distributions/ballerina-slalpha2/bre/lib/handlebars-4.0.6.jar) to method java.util.Collections$EmptyMap.isEmpty()
WARNING: Please consider reporting this to the maintainers of com.github.jknack.handlebars.context.MemberValueResolver
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Successfully generated ballerina file.

Expected output:

Downloading protoc executor file - protoc-3.9.1-osx-x86_64.exe
Download successfully completed. Executor file path - /var/folders/p8/hxg5f9kd2bj8svp8v12m9tj40000gn/T/protoc-3.9.1-osx-x86_64.exe
Successfully extracted library files.
Successfully generated ballerina file.