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protoc-gen-jersey developed by FullContact
package com.fullcontact.rpc.jersey;
import com.fullcontact.rpc.jersey.util.ProtobufDescriptorJavaUtil;
import com.fullcontact.rpc.jersey.yaml.YamlHttpConfig;
import com.fullcontact.rpc.jersey.yaml.YamlHttpRule;
import com.github.mustachejava.DefaultMustacheFactory;
import com.github.mustachejava.Mustache;
import com.github.mustachejava.MustacheFactory;
import com.google.api.AnnotationsProto;
import com.google.api.HttpRule;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.CaseFormat;
import com.google.common.base.CharMatcher;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import com.google.protobuf.*;
import com.google.protobuf.compiler.PluginProtos;
import lombok.Builder;
import lombok.Value;
import java.io.*;
import java.util.*;
import java.util.stream.Collectors;
/**
* Jersey JSON/proto REST gRPC gateway compiler
*
* For every gRPC method annotated with google.api.http options, this compiler emits a Jersey resource method.
*
* @author Michael Rose (xorlev)
*/
public class CodeGenerator {
public PluginProtos.CodeGeneratorResponse generate(PluginProtos.CodeGeneratorRequest request)
throws Descriptors.DescriptorValidationException {
Set options = Sets.newHashSet(Splitter.on(',').split(request.getParameter()));
boolean isProxy = options.contains("proxy");
Map lookup = new HashMap<>();
PluginProtos.CodeGeneratorResponse.Builder response = PluginProtos.CodeGeneratorResponse.newBuilder();
List fileDescriptors = Lists.newArrayList(
DescriptorProtos.MethodOptions.getDescriptor().getFile(),
AnnotationsProto.getDescriptor(),
HttpRule.getDescriptor().getFile()
);
Optional yamlConfig = YamlHttpConfig.getFromOptions(options);
for(DescriptorProtos.FileDescriptorProto fdProto : request.getProtoFileList()) {
// Descriptors are provided in dependency-topological order
// each time we collect a new FileDescriptor, we add it to a
// mutable list of descriptors and append the entire dependency
// chain to each new FileDescriptor to allow crossLink() to function.
// TODO(xorlev): might have to be more selective about deps in future
Descriptors.FileDescriptor fd = Descriptors.FileDescriptor.buildFrom(
fdProto, fileDescriptors.toArray(new Descriptors.FileDescriptor[] {})
);
fileDescriptors.add(fd);
// if type starts with a ".", it's in this package
// otherwise it's fully qualified
String protoPackage = fdProto.getPackage();
for(DescriptorProtos.DescriptorProto d : fdProto.getMessageTypeList()) {
String prefix = ".";
if(!Strings.isNullOrEmpty(protoPackage)) {
prefix += protoPackage + ".";
}
lookup.put(prefix + d.getName(), fd.findMessageTypeByName(d.getName()));
}
// Find RPC methods with HTTP extensions
List methodsToGenerate = new ArrayList<>();
for(Descriptors.ServiceDescriptor serviceDescriptor : fd.getServices()) {
DescriptorProtos.ServiceDescriptorProto serviceDescriptorProto = serviceDescriptor.toProto();
for(DescriptorProtos.MethodDescriptorProto methodProto : serviceDescriptorProto.getMethodList()) {
String fullMethodName = serviceDescriptor.getFullName() +"." + methodProto.getName();
if(yamlConfig.isPresent()) { //Check to see if the rules are defined in the YAML
for(YamlHttpRule rule : yamlConfig.get().getRules()) {
if(rule.getSelector().equals(fullMethodName) || rule.getSelector().equals("*")) { //TODO: com.foo.*
DescriptorProtos.MethodOptions yamlOptions = DescriptorProtos.MethodOptions.newBuilder()
.setExtension(AnnotationsProto.http, rule.buildHttpRule())
.build();
methodProto = DescriptorProtos.MethodDescriptorProto.newBuilder()
.mergeFrom(methodProto)
.setOptions(yamlOptions)
.build();
}
}
}
if(methodProto.getOptions().hasExtension(AnnotationsProto.http)) {
// TODO(xorlev): support server streaming
if(methodProto.getServerStreaming() || methodProto.getClientStreaming())
throw new IllegalArgumentException("http annotations cannot be used with streaming methods");
methodsToGenerate.add(new ServiceAndMethod(serviceDescriptor, methodProto));
}
}
}
if(!methodsToGenerate.isEmpty())
generateResource(response, lookup, fdProto, methodsToGenerate, isProxy);
}
return response.build();
}
private void generateResource(
PluginProtos.CodeGeneratorResponse.Builder response,
Map descriptorTable,
DescriptorProtos.FileDescriptorProto fileDescriptorProto,
List generate,
boolean isProxy) {
ResourceToGenerate r = buildResourceSpec(descriptorTable, fileDescriptorProto, generate, isProxy);
MustacheFactory mf = new DefaultMustacheFactory();
Mustache mustache = mf.compile("resource.tmpl.java");
StringWriter writer = new StringWriter();
mustache.execute(writer, r);
response.addFile(PluginProtos.CodeGeneratorResponse.File.newBuilder()
.setContent(writer.toString())
.setName(r.getFileName())
.build());
System.err.println(writer.toString());
}
/**
* Creates a generator spec for a given service resource and all of the methods.
*
* @param descriptorTable mapping of proto.path.MessageType to the descriptor instance
* @param fileDescriptorProto file descriptor of the origin service
* @param methodSpecs list of methods in the given service
* @param isProxy should this resource use client stubs or implbase?
* @return
*/
@VisibleForTesting
ResourceToGenerate buildResourceSpec(
Map descriptorTable,
DescriptorProtos.FileDescriptorProto fileDescriptorProto,
List methodSpecs,
boolean isProxy) {
Descriptors.ServiceDescriptor serviceDescriptor = methodSpecs.get(0).getServiceDescriptor();
DescriptorProtos.ServiceDescriptorProto sdp = methodSpecs.get(0).getServiceDescriptor().toProto();
String packageName = ProtobufDescriptorJavaUtil.javaPackage(fileDescriptorProto);
String className = ProtobufDescriptorJavaUtil.jerseyResourceClassName(sdp);
String grpcImplClass = (isProxy)?
ProtobufDescriptorJavaUtil.grpcStubClass(fileDescriptorProto, sdp):
ProtobufDescriptorJavaUtil.grpcImplBaseClass(fileDescriptorProto, sdp);
String fileName = packageName.replace('.', '/') + "/" + className + ".java";
ImmutableList.Builder methods = ImmutableList.builder();
for(ServiceAndMethod sam : methodSpecs) {
Descriptors.Descriptor inputDescriptor = descriptorTable.get(sam.getMethodDescriptor().getInputType());
Descriptors.Descriptor outputDescriptor = descriptorTable.get(sam.getMethodDescriptor().getOutputType());
List methodToGenerate = parseRule(sam, inputDescriptor, outputDescriptor);
methods.addAll(methodToGenerate);
}
return ResourceToGenerate
.builder()
.serviceDescriptor(serviceDescriptor)
.javaPackage(ProtobufDescriptorJavaUtil.javaPackage(fileDescriptorProto))
.className(className)
.grpcStub(grpcImplClass)
.methods(methods.build())
.parseHeaders(isProxy)
.fileName(fileName)
.build();
}
/**
* Generates a {@link ResourceMethodToGenerate} spec from the {@link ServiceAndMethod} plus the input/output RPC
* message descriptors
*
* @param sam named tuple of (service descriptor proto, method descriptor proto)
* @param inputDescriptor RPC input descriptor
* @param outputDescriptor RPC output descriptor
* @return list of handlers to handle the given RPC method. Usually a single result, but can be multiple if
* additional_bindings is defined.
*/
@VisibleForTesting
ImmutableList parseRule(ServiceAndMethod sam,
Descriptors.Descriptor inputDescriptor,
Descriptors.Descriptor outputDescriptor) {
HttpRule baseRule = sam.getMethodDescriptor().getOptions().getExtension(AnnotationsProto.http);
ImmutableList rules = ImmutableList.builder()
.add(baseRule)
.addAll(baseRule.getAdditionalBindingsList())
.build();
ImmutableList.Builder methodsToGenerate = ImmutableList.builder();
int methodIndex = 0;
for(HttpRule rule : rules) {
String method = rule.getPatternCase().toString();
String path = "";
switch(rule.getPatternCase()) {
case GET:
path = rule.getGet();
break;
case PUT:
path = rule.getPut();
break;
case POST:
path = rule.getPost();
break;
case DELETE:
path = rule.getDelete();
break;
case PATCH:
path = rule.getPatch();
break;
case CUSTOM:
throw new IllegalArgumentException("Jersey compiler does not support custom HTTP verbs.");
case PATTERN_NOT_SET:
throw new IllegalArgumentException("Pattern (GET,PUT,POST,DELETE,PATCH) must be set.");
}
if(path.trim().isEmpty())
throw new IllegalArgumentException("rule path must be set");
// TODO(xorlev): check for URL overlap
PathParser.ParsedPath parsedPath = PathParser.parse(path);
ImmutableList pathParams = parsePathParams(inputDescriptor, parsedPath);
String bodyFieldPath = Strings.emptyToNull(rule.getBody());
if(bodyFieldPath != null && !bodyFieldPath.equals("*")) {
ImmutableList fieldDescriptor =
ProtobufDescriptorJavaUtil.fieldPath(inputDescriptor, bodyFieldPath);
if(fieldDescriptor.isEmpty()) {
List pathSegments = Splitter.on('.').omitEmptyStrings().trimResults().splitToList(path);
while(!pathSegments.isEmpty()) {
pathSegments.remove(pathSegments.size() - 1);
fieldDescriptor = ProtobufDescriptorJavaUtil.fieldPath(inputDescriptor, bodyFieldPath);
if(!fieldDescriptor.isEmpty()) {
// TODO: remove bodyFieldPath segments until we have a fieldDescriptor
List availableFields = Iterables.getLast(fieldDescriptor).getMessageType()
.getFields()
.stream()
.map(Descriptors.FieldDescriptor::getName)
.collect(Collectors.toList());
throw new IllegalArgumentException("'body' attribute refers to non-existent field " +
"'" + bodyFieldPath + "'. Available fields: " +
availableFields);
}
}
}
}
methodsToGenerate.add(new ResourceMethodToGenerate(
sam.getMethodDescriptor().getName(),
method,
parsedPath.toPath(),
pathParams,
bodyFieldPath,
ProtobufDescriptorJavaUtil.genClassName(inputDescriptor),
ProtobufDescriptorJavaUtil.genClassName(outputDescriptor),
methodIndex++
));
}
return methodsToGenerate.build();
}
public static ImmutableList parsePathParams(Descriptors.Descriptor inputDescriptor, PathParser.ParsedPath path) {
ImmutableList.Builder pathParams = ImmutableList.builder();
path.visit(new PathParser.EmptySegmentVisitor() {
@Override
public void visit(PathParser.NamedVariable namedVariable) {
ImmutableList fieldDescriptor =
ProtobufDescriptorJavaUtil.fieldPath(inputDescriptor, namedVariable.getName());
if(fieldDescriptor.isEmpty())
throw new IllegalArgumentException("Couldn't find path param: " + namedVariable.getName()
+ " in input type: " + inputDescriptor.toProto());
Descriptors.FieldDescriptor descriptor = Iterables.getLast(fieldDescriptor);
if(descriptor.isMapField() || descriptor.isRepeated())
throw new IllegalArgumentException(
"Cannot map path param '" + namedVariable.getName() + "' as URL mapping is not supported " +
"for map or repeated field types."
);
pathParams.add(new PathParam(namedVariable.getName(), fieldDescriptor));
}
});
return pathParams.build();
}
@Value
@Builder
static class ResourceToGenerate {
Descriptors.ServiceDescriptor serviceDescriptor;
String javaPackage;
String className;
String grpcStub; // fully-qualified class name;
List methods;
boolean parseHeaders;
String fileName;
String sourceProtoFile() {
return serviceDescriptor.getFile().getName();
}
}
@Value
static class PathParam {
String name;
ImmutableList fieldDescriptor;
String nameSanitized() {
return CharMatcher.javaLetterOrDigit().retainFrom(name);
}
List descriptorPath() {
return fieldDescriptor.stream()
.map(Descriptors.FieldDescriptor::getName)
.collect(Collectors.toList());
}
String descriptorJoined() {
return Joiner.on(',').join(descriptorPath());
}
}
@Value
static class ResourceMethodToGenerate {
String methodName;
String method; // GET, POST...
String path;
List pathParams;
String bodyFieldPath;
String requestType;
String responseType;
int methodIndex;
String methodNameLower() {
return CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_CAMEL, methodName);
}
}
/**
* Named tuple of (service descriptor, method descriptor proto)
*/
@Value
static class ServiceAndMethod {
Descriptors.ServiceDescriptor serviceDescriptor;
DescriptorProtos.MethodDescriptorProto methodDescriptor;
}
}