Implementing client gen using OkHttp

Dockerfile

@@ -0,0 +1,22 @@
+# Dockerfile for building artifacts
+FROM gradle:5.4.1-jdk8
+MAINTAINER chris@thinkdataworks.com
+
+ENV APPDIR /app
+ENV PROTOC_VERSION 3.5.1
+
+WORKDIR $APPDIR
+RUN mkdir -p $APPDIR
+
+RUN apt-get update -yqq && \
+    apt-get install -yqq build-essential
+
+ENV CLASSPATH ".:/usr/local/lib:$CLASSPATH"
+
+# install protoc; used for protobuff stuff
+RUN curl -OL https://storage.googleapis.com/tdw-static/mirrored/protoc-${PROTOC_VERSION}-linux-x86_64.zip && \
+    unzip protoc-${PROTOC_VERSION}-linux-x86_64.zip -d protoc3 && \
+    mv protoc3/bin/* /usr/local/bin/ && \
+    mv protoc3/include/* /usr/local/include/
+
+COPY . $APPDIR

README.md

@@ -38,6 +38,12 @@ To build the various components, run the following:
     git clone git@github.com:devork/flit.git
     cd flit
     ./gradlew clean build pack
+
+### Building with docker
+
+```bash
+    $ docker-compose run gen ./gradlew build pack 
+```
 
 ### Installation
 
@@ -66,7 +72,7 @@ The flit plugin accepts the following plugin parameters:
 
 | Name          | Required  | Type                          | Description                                               |
 |:--------------|:---------:|:------------------------------|:----------------------------------------------------------|
-| `target`      | Y         | `enum[server]`                | The type of target to generate e.g. server, client etc    |
+| `target`      | Y         | `enum[server,client]`                | The type of target to generate e.g. server, client etc    |
 | `type`        | Y         | `enum[spring,undertow,boot]`  | Type of target to generate                                |
 | `context`     | N         | `string`                      | Base context for routing, default is `/twirp`             |
 

docker-compose.yml

@@ -0,0 +1,8 @@
+version: "3.4"
+
+services:
+  gen:
+    build: .
+    volumes:
+      - .:/app
+    command: sleep 10000

plugin/build.gradle

@@ -40,6 +40,7 @@ dependencies {
     compile 'com.google.protobuf:protobuf-java:3.5.1'
     compile 'com.google.protobuf:protobuf-java-util:3.5.1'
     compile 'com.squareup:javapoet:1.11.1'
+    compile group: 'com.squareup.okhttp3', name: 'okhttp', version: '4.0.0'
 
     compileOnly('org.projectlombok:lombok:+')
 

plugin/gradle.properties

@@ -1 +1 @@
-version=1.0.0
+version=1.1.0

plugin/src/main/java/com/flit/protoc/Plugin.java

@@ -2,6 +2,7 @@
 
 import com.flit.protoc.gen.Generator;
 import com.flit.protoc.gen.GeneratorException;
+import com.flit.protoc.gen.client.okhttp.OkHttpGenerator;
 import com.flit.protoc.gen.server.spring.SpringGenerator;
 import com.flit.protoc.gen.server.undertow.UndertowGenerator;
 import com.google.protobuf.compiler.PluginProtos.CodeGeneratorRequest;
@@ -53,6 +54,13 @@ private Generator resolveGenerator(Map<String, Parameter> params) {
           default:
             throw new GeneratorException("Unknown server type: " + params.get(PARAM_TYPE).getValue());
         }
+      case "client":
+        switch(params.get(PARAM_TYPE).getValue()) {
+          case "okhttp":
+            return new OkHttpGenerator();
+          default:
+            throw new GeneratorException("Unknown client type: " + params.get(PARAM_TYPE).getValue());
+        }
       default:
         throw new GeneratorException("Unknown target type: " + params.get(PARAM_TARGET).getValue());
     }

plugin/src/main/java/com/flit/protoc/gen/server/BaseGenerator.java → plugin/src/main/java/com/flit/protoc/gen/BaseGenerator.java

@@ -1,4 +1,4 @@
-package com.flit.protoc.gen.server;
+package com.flit.protoc.gen;
 
 import com.google.protobuf.DescriptorProtos;
 import com.google.protobuf.compiler.PluginProtos;

plugin/src/main/java/com/flit/protoc/gen/server/TypeMapper.java → plugin/src/main/java/com/flit/protoc/gen/TypeMapper.java

@@ -1,4 +1,4 @@
-package com.flit.protoc.gen.server;
+package com.flit.protoc.gen;
 
 import com.google.protobuf.DescriptorProtos;
 import com.squareup.javapoet.ClassName;

plugin/src/main/java/com/flit/protoc/gen/client/BaseClientGenerator.java

@@ -0,0 +1,38 @@
+package com.flit.protoc.gen.client;
+
+import com.flit.protoc.Parameter;
+import com.flit.protoc.gen.BaseGenerator;
+import com.flit.protoc.gen.Generator;
+import com.flit.protoc.gen.TypeMapper;
+import com.google.protobuf.DescriptorProtos;
+import com.google.protobuf.compiler.PluginProtos;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import static com.flit.protoc.Parameter.PARAM_CONTEXT;
+
+public abstract class BaseClientGenerator implements Generator {
+    @Override public List<PluginProtos.CodeGeneratorResponse.File> generate(PluginProtos.CodeGeneratorRequest request, Map<String, Parameter> params) {
+        List<PluginProtos.CodeGeneratorResponse.File> files = new ArrayList<>();
+        String context = getContext(params);
+        TypeMapper mapper = new TypeMapper(request.getProtoFileList());
+        request.getProtoFileList().forEach(proto -> {
+            proto.getServiceList().forEach(s -> {
+                files.addAll(new ClientGenerator(proto, s, mapper).getFiles());
+                files.addAll(getRpcGenerator(proto, s, context, mapper).getFiles());
+            });
+        });
+        return files;
+    }
+
+    private static String getContext(Map<String, Parameter> params) {
+        if (params.containsKey(PARAM_CONTEXT)) {
+            return params.get(PARAM_CONTEXT).getValue();
+        }
+        return null;
+    }
+
+    protected abstract BaseGenerator getRpcGenerator(DescriptorProtos.FileDescriptorProto proto, DescriptorProtos.ServiceDescriptorProto service, String context, TypeMapper mapper);
+}

plugin/src/main/java/com/flit/protoc/gen/client/ClientGenerator.java

@@ -0,0 +1,38 @@
+package com.flit.protoc.gen.client;
+
+import com.flit.protoc.gen.BaseGenerator;
+import com.flit.protoc.gen.TypeMapper;
+import com.google.protobuf.DescriptorProtos;
+import com.google.protobuf.compiler.PluginProtos;
+import com.squareup.javapoet.ClassName;
+import com.squareup.javapoet.MethodSpec;
+import com.squareup.javapoet.TypeSpec;
+
+import javax.lang.model.element.Modifier;
+import java.util.Collections;
+import java.util.List;
+
+public class ClientGenerator extends BaseGenerator {
+    private final TypeSpec.Builder rpcInterface;
+
+    public ClientGenerator(DescriptorProtos.FileDescriptorProto proto, DescriptorProtos.ServiceDescriptorProto s, TypeMapper mapper) {
+        super(proto, s, mapper);
+        rpcInterface = TypeSpec.interfaceBuilder(ClassName.get(javaPackage, "Rpc" + service.getName()));
+        rpcInterface.addModifiers(Modifier.PUBLIC);
+        service.getMethodList().forEach(this::addDispatchMethod);
+    }
+
+    private void addDispatchMethod(DescriptorProtos.MethodDescriptorProto m) {
+        rpcInterface.addMethod(MethodSpec.methodBuilder("dispatch" + m.getName())
+                .addParameter(mapper.get(m.getInputType()), "in")
+                .addModifiers(Modifier.PUBLIC, Modifier.ABSTRACT)
+                .returns(mapper.get(m.getOutputType()))
+                .addException(Exception.class)
+                .build());
+    }
+
+    @Override
+    public List<PluginProtos.CodeGeneratorResponse.File> getFiles() {
+        return Collections.singletonList(toFile(getServiceInterface(), rpcInterface.build()));
+    }
+}

plugin/src/main/java/com/flit/protoc/gen/client/Types.java

@@ -0,0 +1,20 @@
+package com.flit.protoc.gen.client;
+
+import com.squareup.javapoet.ClassName;
+import com.squareup.javapoet.ParameterizedTypeName;
+
+import java.util.function.Function;
+
+public class Types {
+    public static final ClassName String = ClassName.get(String.class);
+    public static final ClassName OkHttpClient = ClassName.bestGuess("okhttp3.OkHttpClient");
+    public static final ClassName Exception = ClassName.get(java.lang.Exception.class);
+    public static final ClassName RequestBody = ClassName.bestGuess("okhttp3.RequestBody");
+    public static final ClassName RequestBuilder = ClassName.bestGuess("okhttp3.Request.Builder");
+    public static final ClassName MediaType = ClassName.bestGuess("okhttp3.MediaType");
+    public static final ClassName InputStream = ClassName.bestGuess("java.io.InputStream");
+    public static final ClassName HttpUrl = ClassName.bestGuess("okhttp3.HttpUrl");
+    public static final ClassName Request = ClassName.bestGuess("okhttp3.Request");
+    public static final ClassName Response = ClassName.bestGuess("okhttp3.Response");
+    public static final ParameterizedTypeName BeforeRequestFunction = ParameterizedTypeName.get(ClassName.bestGuess("java.util.function.Function"), ClassName.bestGuess("BeforeRequestPayload"), RequestBuilder);
+}

plugin/src/main/java/com/flit/protoc/gen/client/okhttp/OkHttpGenerator.java

@@ -0,0 +1,14 @@
+package com.flit.protoc.gen.client.okhttp;
+
+import com.flit.protoc.gen.BaseGenerator;
+import com.flit.protoc.gen.client.BaseClientGenerator;
+import com.flit.protoc.gen.TypeMapper;
+import com.google.protobuf.DescriptorProtos;
+
+public class OkHttpGenerator extends BaseClientGenerator {
+    @Override
+    protected BaseGenerator getRpcGenerator(
+            DescriptorProtos.FileDescriptorProto proto, DescriptorProtos.ServiceDescriptorProto service, String context, TypeMapper mapper) {
+        return new RpcGenerator(proto, service, context, mapper);
+    }
+}

plugin/src/main/java/com/flit/protoc/gen/client/okhttp/RpcGenerator.java

@@ -0,0 +1,129 @@
+package com.flit.protoc.gen.client.okhttp;
+
+import com.flit.protoc.gen.BaseGenerator;
+import com.flit.protoc.gen.TypeMapper;
+import com.google.protobuf.DescriptorProtos;
+import com.google.protobuf.compiler.PluginProtos;
+import com.squareup.javapoet.*;
+
+import java.util.Collections;
+import java.util.List;
+
+import static com.flit.protoc.gen.server.Types.ErrorCode;
+import static com.flit.protoc.gen.server.Types.FlitException;
+import static javax.lang.model.element.Modifier.*;
+import static com.flit.protoc.gen.client.Types.*;
+
+public class RpcGenerator extends BaseGenerator {
+    private final String context;
+    private final TypeSpec.Builder rpcDispatcher;
+
+    RpcGenerator(DescriptorProtos.FileDescriptorProto proto, DescriptorProtos.ServiceDescriptorProto service, String context, TypeMapper mapper) {
+        super(proto, service, mapper);
+        this.context = getContext(context);
+        rpcDispatcher = TypeSpec.classBuilder(getClientName(service))
+                .addModifiers(PUBLIC);
+        addRequestPayload();
+        addStaticFields();
+        addInstanceFields();
+        addConstructor();
+        addBeforeRequestFunctionSetter();
+        service.getMethodList().forEach(this::writeDispatchMethod);
+    }
+
+    private ClassName getClientName(DescriptorProtos.ServiceDescriptorProto service) {
+        return ClassName.get(javaPackage, "Rpc" + service.getName() + "Dispatcher");
+    }
+
+    private void addBeforeRequestFunctionSetter() {
+        rpcDispatcher.addMethod(
+        MethodSpec.methodBuilder("setBeforeRequest")
+        .addModifiers(PUBLIC)
+        .addParameter(BeforeRequestFunction, "beforeRequest")
+        .addStatement("this.beforeRequest = beforeRequest")
+        .build()
+        );
+    }
+
+    private void addRequestPayload() {
+        // Add inner class for request payload
+        TypeSpec.Builder payloadBuilder = TypeSpec.classBuilder("BeforeRequestPayload").addModifiers(PUBLIC);
+        payloadBuilder.addMethod(MethodSpec.constructorBuilder()
+        .addModifiers(PUBLIC)
+        .addParameter(RequestBuilder, "builder")
+        .addParameter(HttpUrl, "url")
+        .addStatement("this.builder = builder")
+        .addStatement("this.url = url")
+        .build());
+        payloadBuilder.addField(FieldSpec.builder(RequestBuilder, "builder").addModifiers(PUBLIC).build());
+        payloadBuilder.addField(FieldSpec.builder(HttpUrl, "url").addModifiers(PUBLIC).build());
+
+        // Add to dispatcher
+        rpcDispatcher.addType(payloadBuilder.build());
+    }
+
+    private void addStaticFields() {
+        // Add service path prix
+        rpcDispatcher.addField(FieldSpec.builder(String, "SERVICE_PATH_PREFIX")
+        .addModifiers(PUBLIC, STATIC, FINAL)
+        .initializer("\"$L/$L$L/\"", context, proto.hasPackage() ? proto.getPackage() + "." : "", service.getName())
+        .build());
+    }
+
+    private void addInstanceFields() {
+        rpcDispatcher.addField(FieldSpec.builder(String, "baseAddress").addModifiers(PRIVATE, FINAL).build());
+        rpcDispatcher.addField(FieldSpec.builder(OkHttpClient, "client").addModifiers(PRIVATE).build());
+        rpcDispatcher.addField(FieldSpec.builder(BeforeRequestFunction, "beforeRequest").build());
+    }
+
+    private void addConstructor() {
+        rpcDispatcher.addMethod(MethodSpec.constructorBuilder()
+        .addModifiers(PUBLIC)
+        .addParameter(String, "address")
+        .addParameter(OkHttpClient, "client")
+        .addStatement("this.baseAddress = address")
+        .addStatement("this.client = client")
+        .build());
+    }
+
+    private void writeDispatchMethod(DescriptorProtos.MethodDescriptorProto m) {
+        ClassName inputType = mapper.get(m.getInputType());
+        ClassName outputType = mapper.get(m.getOutputType());
+        rpcDispatcher.addMethod(
+          MethodSpec.methodBuilder("dispatch" + m.getName())
+          .addModifiers(PUBLIC)
+          .addParameter(inputType, "in")
+          .returns(outputType)
+          .addException(Exception)
+          .addStatement("$T url = $T.parse(baseAddress + SERVICE_PATH_PREFIX + $S)", HttpUrl, HttpUrl, m.getName())
+          .addStatement("$T requestBody = $T.create(in.toByteArray(), $T.get(\"application/protobuf\"))", RequestBody, RequestBody, MediaType)
+          .addStatement("$T builder = new $T()", RequestBuilder, RequestBuilder)
+          .beginControlFlow("if(beforeRequest != null)")
+          .addStatement("builder = beforeRequest.apply(new BeforeRequestPayload(builder, url))")
+          .endControlFlow()
+          .addStatement("builder.addHeader(\"Accept\", \"application/protobuf\")")
+          .addStatement("builder.addHeader(\"Content-Type\", \"application/protobuf\")")
+          .addStatement("builder.addHeader(\"Flit-Version\", \"v1.1.0\")")
+          .addStatement("builder.url(url)")
+          .addStatement("builder.post(requestBody)")
+          .addStatement("$T request = builder.build()", Request)
+          .addStatement("String responseString")
+          .addStatement("$T responseStream", InputStream)
+          .beginControlFlow("try($T response = client.newCall(request).execute())", Response)
+          .beginControlFlow("if(response.code() != 200)")
+          .addStatement("responseString = response.body().string()")
+          .addStatement("throw $T.builder().withErrorCode($T.INTERNAL).withMeta(\"message\", responseString).withMessage(\"RPC error\").build()", FlitException, ErrorCode)
+          .nextControlFlow("else")
+          .addStatement("responseStream = response.body().byteStream()")
+          .addStatement("return $T.parseFrom(responseStream)", outputType)
+          .endControlFlow()
+          .endControlFlow()
+          .build()
+        );
+    }
+
+    @Override
+    public List<PluginProtos.CodeGeneratorResponse.File> getFiles() {
+        return Collections.singletonList(toFile(getClientName(service), rpcDispatcher.build()));
+    }
+}

plugin/src/main/java/com/flit/protoc/gen/server/BaseServerGenerator.java

@@ -1,7 +1,9 @@
 package com.flit.protoc.gen.server;
 
 import com.flit.protoc.Parameter;
+import com.flit.protoc.gen.BaseGenerator;
 import com.flit.protoc.gen.Generator;
+import com.flit.protoc.gen.TypeMapper;
 import com.google.protobuf.DescriptorProtos.FileDescriptorProto;
 import com.google.protobuf.DescriptorProtos.ServiceDescriptorProto;
 import com.google.protobuf.compiler.PluginProtos.CodeGeneratorRequest;

plugin/src/main/java/com/flit/protoc/gen/server/ServiceGenerator.java

@@ -1,5 +1,7 @@
 package com.flit.protoc.gen.server;
 
+import com.flit.protoc.gen.BaseGenerator;
+import com.flit.protoc.gen.TypeMapper;
 import com.google.protobuf.DescriptorProtos;
 import com.google.protobuf.compiler.PluginProtos;
 import com.squareup.javapoet.ClassName;
@@ -34,7 +36,8 @@ private void addHandleMethod(DescriptorProtos.MethodDescriptorProto m) {
       .build());
   }
 
-  @Override public List<PluginProtos.CodeGeneratorResponse.File> getFiles() {
+  @Override
+  public List<PluginProtos.CodeGeneratorResponse.File> getFiles() {
     return Collections.singletonList(toFile(getServiceInterface(), rpcInterface.build()));
   }
 }

plugin/src/main/java/com/flit/protoc/gen/server/spring/RpcGenerator.java

@@ -1,7 +1,7 @@
 package com.flit.protoc.gen.server.spring;
 
-import com.flit.protoc.gen.server.BaseGenerator;
-import com.flit.protoc.gen.server.TypeMapper;
+import com.flit.protoc.gen.BaseGenerator;
+import com.flit.protoc.gen.TypeMapper;
 import com.flit.protoc.gen.server.Types;
 import com.google.protobuf.DescriptorProtos;
 import com.google.protobuf.compiler.PluginProtos;

plugin/src/main/java/com/flit/protoc/gen/server/spring/SpringGenerator.java

@@ -1,8 +1,8 @@
 package com.flit.protoc.gen.server.spring;
 
-import com.flit.protoc.gen.server.BaseGenerator;
+import com.flit.protoc.gen.BaseGenerator;
 import com.flit.protoc.gen.server.BaseServerGenerator;
-import com.flit.protoc.gen.server.TypeMapper;
+import com.flit.protoc.gen.TypeMapper;
 import com.google.protobuf.DescriptorProtos.FileDescriptorProto;
 import com.google.protobuf.DescriptorProtos.ServiceDescriptorProto;