When working with gRPC, we need to generate the gRPC client and server interfaces from our .proto service definition via protocol buffer compiler (protoc) or using Gradle or Maven protoc build plugin.
Flow now: protobuf file -> java code -> gRPC client.
So, is there any way to skip this step?
How to create a generic gRPC client that can call the server directly from the protobuf file without compile into java code?
Or, is there a way to Generated Code at runtime?
Flow expect: protobuf file -> gRPC client.
I want to build a generic gRPC client system with the input are protobuf files along with description of method, package, message request ... without having to compile again for each protobuf.
Thank you very much.
Protobuf systems really need protoc to be run. However, the generated code could be skipped. Instead of passing something like --java_out and --grpc_java_out to protoc you can pass --descriptor_set_out=FILE which will parse the .proto file into a descriptor file. A descriptor file is a proto-encoded FileDescriptorSet. This is the same basic format as used with the reflection service.
Once you have a descriptor, you can load it a FileDescriptor at a time and create a DynamicMessage.
Then for the gRPC piece, you need to create a gRPC MethodDescriptor.
static MethodDescriptor from(
Descriptors.MethodDescriptor methodDesc
) {
return MethodDescriptor.<DynamicMessage, DynamicMessage>newBuilder()
// UNKNOWN is fine, but the "correct" value can be computed from
// methodDesc.toProto().getClientStreaming()/getServerStreaming()
.setType(getMethodTypeFromDesc(methodDesc))
.setFullMethodName(MethodDescriptor.generateFullMethodName(
serviceDesc.getFullName(), methodDesc.getName()))
.setRequestMarshaller(ProtoUtils.marshaller(
DynamicMessage.getDefaultInstance(methodDesc.getInputType())))
.setResponseMarshaller(ProtoUtils.marshaller(
DynamicMessage.getDefaultInstance(methodDesc.getOutputType())))
.build();
static MethodDescriptor.MethodType getMethodTypeFromDesc(
Descriptors.MethodDescriptor methodDesc
) {
if (!methodDesc.isServerStreaming()
&& !methodDesc.isClientStreaming()) {
return MethodDescriptor.MethodType.UNARY;
} else if (methodDesc.isServerStreaming()
&& !methodDesc.isClientStreaming()) {
return MethodDescriptor.MethodType.SERVER_STREAMING;
} else if (!methodDesc.isServerStreaming()) {
return MethodDescriptor.MethodType.CLIENT_STREAMING);
} else {
return MethodDescriptor.MethodType.BIDI_STREAMING);
}
}
At that point you have everything you need and can call Channel.newCall(method, CallOptions.DEFAULT) in gRPC. You're also free to use ClientCalls to use something more similar to the stub APIs.
So dynamic calls are definitely possible, and is used for things like grpcurl. But it also is not easy and so is generally only done when necessary.
I did it in Java, and the step is:
Call reflection service to get FileDescriptorProto list by method name
Get FileDescriptor of method from FileDescriptorProto list by package name, service name
Get MethodDescriptor from ServiceDescriptor which get from the FileDescriptor
Generate a MethodDescriptor<DynamicMessage, DynamicMessage> by MethodDescriptor
Build request DynamicMessage from content like JSON or others
Call method
Parse response content to JSON from DynamicMessage response
You can reference the full sample in project helloworlde/grpc-java-sample#reflection
And proto is:
syntax = "proto3";
package io.github.helloworlde.grpc;
option go_package = "api;grpc_gateway";
option java_package = "io.github.helloworlde.grpc";
option java_multiple_files = true;
option java_outer_classname = "HelloWorldGrpc";
service HelloService{
rpc SayHello(HelloMessage) returns (HelloResponse){
}
}
message HelloMessage {
string message = 2;
}
message HelloResponse {
string message = 1;
}
Start server for this proto by yourself, and the full code in Java just like:
import com.google.protobuf.ByteString;
import com.google.protobuf.DescriptorProtos;
import com.google.protobuf.Descriptors;
import com.google.protobuf.DynamicMessage;
import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.TypeRegistry;
import com.google.protobuf.util.JsonFormat;
import io.grpc.CallOptions;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.MethodDescriptor;
import io.grpc.protobuf.ProtoUtils;
import io.grpc.reflection.v1alpha.ServerReflectionGrpc;
import io.grpc.reflection.v1alpha.ServerReflectionRequest;
import io.grpc.reflection.v1alpha.ServerReflectionResponse;
import io.grpc.stub.ClientCalls;
import io.grpc.stub.StreamObserver;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
#Slf4j
public class ReflectionCall {
public static void main(String[] args) throws InterruptedException {
// 反射方法的格式只支持 package.service.method 或者 package.service
String methodSymbol = "io.github.helloworlde.grpc.HelloService.SayHello";
String requestContent = "{\"message\": \"Reflection\"}";
// 构建 Channel
ManagedChannel channel = ManagedChannelBuilder.forAddress("127.0.0.1", 9090)
.usePlaintext()
.build();
// 使用 Channel 构建 BlockingStub
ServerReflectionGrpc.ServerReflectionStub reflectionStub = ServerReflectionGrpc.newStub(channel);
// 响应观察器
StreamObserver<ServerReflectionResponse> streamObserver = new StreamObserver<ServerReflectionResponse>() {
#Override
public void onNext(ServerReflectionResponse response) {
try {
// 只需要关注文件描述类型的响应
if (response.getMessageResponseCase() == ServerReflectionResponse.MessageResponseCase.FILE_DESCRIPTOR_RESPONSE) {
List<ByteString> fileDescriptorProtoList = response.getFileDescriptorResponse().getFileDescriptorProtoList();
handleResponse(fileDescriptorProtoList, channel, methodSymbol, requestContent);
} else {
log.warn("未知响应类型: " + response.getMessageResponseCase());
}
} catch (Exception e) {
log.error("处理响应失败: {}", e.getMessage(), e);
}
}
#Override
public void onError(Throwable t) {
}
#Override
public void onCompleted() {
log.info("Complete");
}
};
// 请求观察器
StreamObserver<ServerReflectionRequest> requestStreamObserver = reflectionStub.serverReflectionInfo(streamObserver);
// 构建并发送获取方法文件描述请求
ServerReflectionRequest getFileContainingSymbolRequest = ServerReflectionRequest.newBuilder()
.setFileContainingSymbol(methodSymbol)
.build();
requestStreamObserver.onNext(getFileContainingSymbolRequest);
channel.awaitTermination(10, TimeUnit.SECONDS);
}
/**
* 处理响应
*/
private static void handleResponse(List<ByteString> fileDescriptorProtoList,
ManagedChannel channel,
String methodFullName,
String requestContent) {
try {
// 解析方法和服务名称
String fullServiceName = extraPrefix(methodFullName);
String methodName = extraSuffix(methodFullName);
String packageName = extraPrefix(fullServiceName);
String serviceName = extraSuffix(fullServiceName);
// 根据响应解析 FileDescriptor
Descriptors.FileDescriptor fileDescriptor = getFileDescriptor(fileDescriptorProtoList, packageName, serviceName);
// 查找服务描述
Descriptors.ServiceDescriptor serviceDescriptor = fileDescriptor.getFile().findServiceByName(serviceName);
// 查找方法描述
Descriptors.MethodDescriptor methodDescriptor = serviceDescriptor.findMethodByName(methodName);
// 发起请求
executeCall(channel, fileDescriptor, methodDescriptor, requestContent);
} catch (Exception e) {
log.error(e.getMessage(), e);
}
}
/**
* 解析并查找方法对应的文件描述
*/
private static Descriptors.FileDescriptor getFileDescriptor(List<ByteString> fileDescriptorProtoList,
String packageName,
String serviceName) throws Exception {
Map<String, DescriptorProtos.FileDescriptorProto> fileDescriptorProtoMap =
fileDescriptorProtoList.stream()
.map(bs -> {
try {
return DescriptorProtos.FileDescriptorProto.parseFrom(bs);
} catch (InvalidProtocolBufferException e) {
e.printStackTrace();
}
return null;
})
.filter(Objects::nonNull)
.collect(Collectors.toMap(DescriptorProtos.FileDescriptorProto::getName, f -> f));
if (fileDescriptorProtoMap.isEmpty()) {
log.error("服务不存在");
throw new IllegalArgumentException("方法的文件描述不存在");
}
// 查找服务对应的 Proto 描述
DescriptorProtos.FileDescriptorProto fileDescriptorProto = findServiceFileDescriptorProto(packageName, serviceName, fileDescriptorProtoMap);
// 获取这个 Proto 的依赖
Descriptors.FileDescriptor[] dependencies = getDependencies(fileDescriptorProto, fileDescriptorProtoMap);
// 生成 Proto 的 FileDescriptor
return Descriptors.FileDescriptor.buildFrom(fileDescriptorProto, dependencies);
}
/**
* 根据包名和服务名查找相应的文件描述
*/
private static DescriptorProtos.FileDescriptorProto findServiceFileDescriptorProto(String packageName,
String serviceName,
Map<String, DescriptorProtos.FileDescriptorProto> fileDescriptorProtoMap) {
for (DescriptorProtos.FileDescriptorProto proto : fileDescriptorProtoMap.values()) {
if (proto.getPackage().equals(packageName)) {
boolean exist = proto.getServiceList()
.stream()
.anyMatch(s -> serviceName.equals(s.getName()));
if (exist) {
return proto;
}
}
}
throw new IllegalArgumentException("服务不存在");
}
/**
* 获取前缀
*/
private static String extraPrefix(String content) {
int index = content.lastIndexOf(".");
return content.substring(0, index);
}
/**
* 获取后缀
*/
private static String extraSuffix(String content) {
int index = content.lastIndexOf(".");
return content.substring(index + 1);
}
/**
* 获取依赖类型
*/
private static Descriptors.FileDescriptor[] getDependencies(DescriptorProtos.FileDescriptorProto proto,
Map<String, DescriptorProtos.FileDescriptorProto> finalDescriptorProtoMap) {
return proto.getDependencyList()
.stream()
.map(finalDescriptorProtoMap::get)
.map(f -> toFileDescriptor(f, getDependencies(f, finalDescriptorProtoMap)))
.toArray(Descriptors.FileDescriptor[]::new);
}
/**
* 将 FileDescriptorProto 转为 FileDescriptor
*/
#SneakyThrows
private static Descriptors.FileDescriptor toFileDescriptor(DescriptorProtos.FileDescriptorProto fileDescriptorProto,
Descriptors.FileDescriptor[] dependencies) {
return Descriptors.FileDescriptor.buildFrom(fileDescriptorProto, dependencies);
}
/**
* 执行方法调用
*/
private static void executeCall(ManagedChannel channel,
Descriptors.FileDescriptor fileDescriptor,
Descriptors.MethodDescriptor originMethodDescriptor,
String requestContent) throws Exception {
// 重新生成 MethodDescriptor
MethodDescriptor<DynamicMessage, DynamicMessage> methodDescriptor = generateMethodDescriptor(originMethodDescriptor);
CallOptions callOptions = CallOptions.DEFAULT;
TypeRegistry registry = TypeRegistry.newBuilder()
.add(fileDescriptor.getMessageTypes())
.build();
// 将请求内容由 JSON 字符串转为相应的类型
JsonFormat.Parser parser = JsonFormat.parser().usingTypeRegistry(registry);
DynamicMessage.Builder messageBuilder = DynamicMessage.newBuilder(originMethodDescriptor.getInputType());
parser.merge(requestContent, messageBuilder);
DynamicMessage requestMessage = messageBuilder.build();
// 调用，调用方式可以通过 originMethodDescriptor.isClientStreaming() 和 originMethodDescriptor.isServerStreaming() 推断
DynamicMessage response = ClientCalls.blockingUnaryCall(channel, methodDescriptor, callOptions, requestMessage);
// 将响应解析为 JSON 字符串
JsonFormat.Printer printer = JsonFormat.printer()
.usingTypeRegistry(registry)
.includingDefaultValueFields();
String responseContent = printer.print(response);
log.info("响应: {}", responseContent);
}
/**
* 重新生成方法描述
*/
private static MethodDescriptor<DynamicMessage, DynamicMessage> generateMethodDescriptor(Descriptors.MethodDescriptor originMethodDescriptor) {
// 生成方法全名
String fullMethodName = MethodDescriptor.generateFullMethodName(originMethodDescriptor.getService().getFullName(), originMethodDescriptor.getName());
// 请求和响应类型
MethodDescriptor.Marshaller<DynamicMessage> inputTypeMarshaller = ProtoUtils.marshaller(DynamicMessage.newBuilder(originMethodDescriptor.getInputType())
.buildPartial());
MethodDescriptor.Marshaller<DynamicMessage> outputTypeMarshaller = ProtoUtils.marshaller(DynamicMessage.newBuilder(originMethodDescriptor.getOutputType())
.buildPartial());
// 生成方法描述, originMethodDescriptor 的 fullMethodName 不正确
return MethodDescriptor.<DynamicMessage, DynamicMessage>newBuilder()
.setFullMethodName(fullMethodName)
.setRequestMarshaller(inputTypeMarshaller)
.setResponseMarshaller(outputTypeMarshaller)
// 使用 UNKNOWN，自动修改
.setType(MethodDescriptor.MethodType.UNKNOWN)
.build();
}
}
There isn't much to prevent this technically. The two big hurdles are:
having a runtime-callable parser for reading the .proto, and
having a general purpose gRPC client available that takes things like the service method name as literals
Both are possible, but neither is trivial.
For 1, the crude way would be to shell/invoke protoc using the descriptor-set option to generate a schema binary, then deserialize that as a FileDescriptorSet (from descriptor.proto); this model gives you access to how protoc sees the file. Some platforms also have native parsers (essentially reimplementing protoc as a library in that platform), for example protobuf-net.Reflection does this in .NET-land
For 2, here's an implementation of that in C#. The approach should be fairly portable to Java, even if the details vary. You can look at a generated implementation to see how it works in any particular language.
(Sorry that the specific examples are C#/.NET, but that's where I live; the approaches should be portable, even if the specific code: not directly)
technically both are possible.
The codegen is simply generating a handful of classes; mainly protobuf messages, grpc method descriptors and stubs. You can implement it or check in the generated code to bypass the codegen. i am not sure what is the benefit of doing this tbh. Also, it will be very annoying if the proto is changed.
It is also possible to do it dynamically using byte codegen as long as you check-in some interfaces/abstract classes to represent those generated stub/method descriptors and protobuf messages. you have to make sure those non dynamic code is in sync with the proto definition though (most likely runtime check/exception).
How can I deploy web pages along with my Restful Project in Embedded Jetty?
I have already setup my Jetty Project to deploy RESTFUL using embedded jetty.
public class App {
private static Server server;
public static void main(String...s) {
initJetty();
}
private static void initJetty(){
try {
URI baseUri = UriBuilder.fromPath(System.getProperty("jetty.uri", "http://127.0.0.1:32081")).build();
server = JettyHttpContainerFactory.createServer(baseUri, new AppResourceConfig());
server.start();
} catch(Exception ex){
stopJetty();
}
}
private static void stopJetty() {
if(server != null){
try {
server.stop();
} catch (Exception e) {
}
}
}
}
public class AppResourceConfig extends ResourceConfig {
private static final String REST_BASE_PACKAGE = "com.dinesh.client.endpoints";
public AppResourceConfig(){
//Base package suffices as it scans all the subpackages recursively.
packages(REST_BASE_PACKAGE)
.register(MultiPartFeature.class)
.register(MoxyJsonFeature.class);
}
}
How can I deploy web pages on the same port using embedded jetty? I want to be able to deploy it using the java -jar command on my terminal.
Try using jetty runner for war/jar/ear
java -jar jetty-runner-9.4.0.M1.jar jetty-app/target/jetty-app.war
I try to get some data from a dbus service and work with it in Java.
I can get the information in cli with the following command:
dbus-send --print-reply --system --dest=com.victronenergy.solarcharger.ttyUSB0 /Dc/0/Voltage com.victronenergy.BusItem.GetValue
The result is:
method return time=1538903662.321580 sender=:1.14 -> destination=:1.806 serial=335692 reply_serial=2
variant double 13.43
What I tried to get this data in Java, is:
After hours of reading, I created an Interface.
package javadbus;
import java.util.Map;
import org.freedesktop.dbus.DBusInterface;
import org.freedesktop.dbus.DBusSignal;
import org.freedesktop.dbus.Variant;
import org.freedesktop.dbus.exceptions.DBusException;
public interface BusItem extends DBusInterface
{
public static class PropertiesChanged extends DBusSignal
{
public final Map<String,Variant> changes;
public PropertiesChanged(String path, Map<String,Variant> changes) throws DBusException
{
super(path, changes);
this.changes = changes;
}
}
public String GetDescription(String language, int length);
public Variant GetValue();
public String GetText();
public int SetValue(Variant value);
public Variant GetMin();
public Variant GetMax();
public int SetDefault();
public Variant GetDefault();
}
Here I call getConnection() and getRemoteObject() successfully.
package javadbus;
import org.freedesktop.dbus.DBusConnection;
import org.freedesktop.dbus.exceptions.DBusException;
import org.freedesktop.dbus.Variant;
public class VictronEnergyDBusSolarCharger {
private String port;
private DBusConnection conn;
public VictronEnergyDBusSolarCharger(String port) {
this.port = port;
try {
this.conn = DBusConnection.getConnection(DBusConnection.SYSTEM);
} catch (DBusException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private String getData(String item) {
BusItem bi;
String data = null;
Variant vData = null;
try {
bi = (BusItem)conn.getRemoteObject("com.victronenergy.solarcharger." + this.port, item, BusItem.class);
vData = bi.GetValue();
//data = bi.GetText();
} catch (DBusException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return data;
}
...
}
It was a big task to resolve all dependecies and get the code compiled. But finaly I did it. So, javac now runs without errors.
But if I try to call the Method GetValue(), I get the following Exception:
[Sender] INFO org.freedesktop.dbus.MessageWriter - <= MethodCall(0,1) { Path=>/org/freedesktop/DBus, Interface=>org.freedesktop.DBus, Member=>Hello, Destination=>org.freedesktop.DBus } { }
[Sender] INFO org.freedesktop.dbus.MessageWriter - <= MethodCall(0,3) { Path=>/Dc/0/Voltage, Interface=>javadbus.BusItem, Member=>GetValue, Destination=>com.victronenergy.solarcharger.ttyUSB0 } { }
Exception in thread "main" org.freedesktop.DBus$Error$UnknownMethod: Method "GetValue" with signature "" on interface "javadbus.BusItem" doesn't exist
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.freedesktop.dbus.Error.getException(Error.java:141)
at org.freedesktop.dbus.Error.throwException(Error.java:171)
at org.freedesktop.dbus.RemoteInvocationHandler.executeRemoteMethod(RemoteInvocationHandler.java:158)
at org.freedesktop.dbus.RemoteInvocationHandler.invoke(RemoteInvocationHandler.java:222)
at com.sun.proxy.$Proxy1.GetValue(Unknown Source)
at javadbus.VictronEnergyDBusSolarCharger.getData(VictronEnergyDBusSolarCharger.java:28)
at javadbus.VictronEnergyDBusSolarCharger.getDcV(VictronEnergyDBusSolarCharger.java:38)
at javadbus.MainClass.main(MainClass.java:7)
Is it necessary to make a implementation of this Method GetValue? But why e.g. how should I do this? I only want to get this Information and not provide it like a Server.
Why was it a big task to get all dependencies?
dbus-java library and dependencies are all available at maven central, so a proper maven project should just work out-of-the-box.
Back to topic:
You don't have to implement GetValue(), but you need a suitable java interface for BusItem.
As far as I can see in the documentation of victronenergy (https://www.victronenergy.com/live/open_source:ccgx:d-bus) , your interface is not correct.
You provide SetDefault()/GetDefault() methods, which are only available on com.victronenergy.settings Objects, but you want to retrieve a com.victronenergy.BusItem (no part of the com.victronenergy.settings package).
This is one error. The second error is: you use the wrong package name for your BusItem class.
In your case DBus will try to resolve an object with the path javadbus.BusItem which is not provided by the connected BusAddress com.victronenergy.solarcharger.ttyUSB0.
The BusItem class has to be in package com.victronenergy or you have to use the annotation #DBusInterfaceName("com.victronenergy.BusItem").
The annotation will tell the DBus library to ignore the java package/class name and use the one provided in the annotation.
The Inteface BusItem had been created by CreateInterface-Script from https://dbus.freedesktop.org/doc/dbus-java/dbus-java/dbus-javase10.html and the XML from Introspect()
But you solved my real problem. I used the annotation #DBusInterfaceName("com.victronenergy.BusItem") now. No Exception anymore an i get data from my solarcharger. Thank you so much!
I try to perform a read opertion on Elasticsearch index right after it was created. Here is simple code to reproduce this situation:
import org.elasticsearch.action.admin.indices.exists.indices.IndicesExistsResponse;
import org.elasticsearch.client.Client;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import static java.net.InetAddress.getLoopbackAddress;
public class ElasticIssue {
static String index = "my_index";
public static void main(String[] args) {
final Client c = getClient();
deleteIndexIfExists(c);
createIndex(c);
//refresh(c);
//flush(c);
//delay();
//indexDoc(c);
getDoc(c);
}
static void getDoc(Client client) {
client.prepareGet(index, "some-type", "1").get();
}
static void indexDoc(Client client) {
client.prepareIndex(index, "another-type", "25").setSource("{}").get();
}
static void createIndex(Client client) {
client.admin().indices().prepareCreate(index).get();
}
static void delay() {
try {Thread.sleep(3000);} catch (InterruptedException e) {}
}
static void flush(Client client) {
client.admin().indices().prepareFlush(index).get();
}
private static void refresh(Client client) {
client.admin().indices().prepareRefresh(index).get();
}
static void deleteIndexIfExists(Client client) {
final IndicesExistsResponse response = client.admin().indices().prepareExists(index).get();
if (response.isExists()) {
deleteIndex(client);
}
}
static void deleteIndex(Client client) {
client.admin().indices().prepareDelete(index).get();
}
static Client getClient() {
final Settings settings = Settings.builder()
.put("cluster.name", "elasticsearch") //default name
.put("node.name", "my-node")
.build();
return TransportClient.builder()
.settings(settings)
.build()
.addTransportAddress(new InetSocketTransportAddress(getLoopbackAddress(), 9300));
}
}
And then I get the following error:
Exception in thread "main" NoShardAvailableActionException[No shard available for [get [my_index][some-type][1]: routing [null]]]; nested: RemoteTransportException[[my-node][172.17.0.2:9300][indices:data/read/get[s]]]; nested: IllegalIndexShardStateException[CurrentState[RECOVERING] operations only allowed when shard state is one of [POST_RECOVERY, STARTED, RELOCATED]];
at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction.perform(TransportSingleShardAction.java:199)
at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction.onFailure(TransportSingleShardAction.java:186)
at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction.access$1300(TransportSingleShardAction.java:115)
at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction$2.handleException(TransportSingleShardAction.java:240)
at org.elasticsearch.transport.TransportService$DirectResponseChannel.processException(TransportService.java:855)
at org.elasticsearch.transport.TransportService$DirectResponseChannel.sendResponse(TransportService.java:833)
at org.elasticsearch.transport.TransportService$4.onFailure(TransportService.java:387)
at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:39)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: RemoteTransportException[[my-node][172.17.0.2:9300][indices:data/read/get[s]]]; nested: IllegalIndexShardStateException[CurrentState[RECOVERING] operations only allowed when shard state is one of [POST_RECOVERY, STARTED, RELOCATED]];
Caused by: [my_index][[my_index][3]] IllegalIndexShardStateException[CurrentState[RECOVERING] operations only allowed when shard state is one of [POST_RECOVERY, STARTED, RELOCATED]]
at org.elasticsearch.index.shard.IndexShard.readAllowed(IndexShard.java:1035)
at org.elasticsearch.index.shard.IndexShard.get(IndexShard.java:651)
at org.elasticsearch.index.get.ShardGetService.innerGet(ShardGetService.java:173)
at org.elasticsearch.index.get.ShardGetService.get(ShardGetService.java:86)
at org.elasticsearch.action.get.TransportGetAction.shardOperation(TransportGetAction.java:101)
at org.elasticsearch.action.get.TransportGetAction.shardOperation(TransportGetAction.java:44)
at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$ShardTransportHandler.messageReceived(TransportSingleShardAction.java:282)
at org.elasticsearch.action.support.single.shard.TransportSingleShardAction$ShardTransportHandler.messageReceived(TransportSingleShardAction.java:275)
at org.elasticsearch.transport.TransportRequestHandler.messageReceived(TransportRequestHandler.java:33)
at org.elasticsearch.transport.RequestHandlerRegistry.processMessageReceived(RequestHandlerRegistry.java:75)
at org.elasticsearch.transport.TransportService$4.doRun(TransportService.java:376)
at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
It seems like Elasticsearch index creation was not complete despite response was already returned. That is a bit frustrating. And if I do any of: delay, index any doc, refresh index, flush index (uncomment any line for this); then read operation performs successfully.
What is the explanation of this behavior? What is a recommended way to make sure that index is ready to work? Listed solutions are found by experiment.
I'am using Elasticsearch 2.3.3 and Java 8. All communication with Elasticsearch is done using Transport protocol (with Java api).
For easier setup here is docker command to get container with all necessary settings:
docker run -p 9200:9200 -p 9300:9300 elasticsearch:2.3.3 -Des.node.name="my-node"
Here is Maven dependency for Elasticsearch Java API:
<dependency>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>2.3.3</version>
</dependency>
You need to wait till the index is created. This is what you can do to wait till the health of index is in yellow status.
After index creation function call the below function :
static void indexStatusCheck(Client client) {
ClusterHealthResponse response = client.admin().cluster().prepareHealth().setIndices(index).setWaitForYellowStatus().get();
if (response.getStatus() == ClusterHealthStatus.RED) {
throw Exception("Index not ready");
}
}
Then you can proceed with the getDoc() call.
I have inherited some Java RMI client/server code, and while it runs fine on one machine, I haven't been able to get it to run in my dev environment.
The problem is when I run the server using the following java.exe -Djava.security.policy=conf\server.policy -SRC;. -Djava.library.path=. org.prog.rmi.RmiServer
I get the following error:
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.lang.ClassNotFoundException: org.prog.rmi.RmiServer_Stub (no security manager: RMI class loader disabled)
at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:396)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:250)
at sun.rmi.transport.Transport$1.run(Transport.java:159)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
...
My server.policy file is
grant {
permission java.security.AllPermission;
};
And my java code:
package org.prog.rmi;
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.RMISecurityManager;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.registry.*;
public class RmiServer extends UnicastRemoteObject
implements RmiServerIntf {
private BatchApi bapi;
private String iniFileLocation;
private String layoutOption;
private int addressCount = 0;
private RefInt apiHandle = new RefInt();
public RmiServer(String iniFileLocation,String layoutOption) throws RemoteException
{ super();
this.iniFileLocation = iniFileLocation;
this.layoutOption = layoutOption;
initAPI();
startupAPI();
openAPI();
}
public static void main(String args[])
{
System.out.println("RMI server started");
// Create and install a security manager
if (System.getSecurityManager() == null)
{
System.setSecurityManager(new RMISecurityManager());
System.out.println("Security manager installed.");
}
else
System.out.println("Security manager already exists.");
try //special exception handler for registry creation
{
LocateRegistry.createRegistry(1099);
System.out.println("java RMI registry created.");
}
catch (RemoteException e)
{
//do nothing, error means registry already exists
System.out.println("java RMI registry already exists.");
}
try
{
//Instantiate RmiServer
for (String arg: args){
System.out.println(arg);
}
RmiServer obj = new RmiServer(args[0],args[1]);
// Bind this object instance to the name "RmiServer"
Naming.rebind("//127.0.0.1/RmiServer", obj);
System.out.println("PeerServer bound in registry");
}
catch (Exception e)
{
System.err.println("RMI server exception:");
e.printStackTrace();
}
}
}
I've seen solutions relating to the java.rmi.server.codebase but didn't have any luck setting this either
You haven't regenerated the stub with rmic, or the Registry doesn't have access to it via its classpath.
After some further investigation and following RMI tutorials it appeared that there was a problem with the RMI registration server on port 1099.
When I stared the RMI registration server on another port (e.g. 2005) and changed these lines of code
LocateRegistry.createRegistry(2005);
and
Naming.rebind("//127.0.0.1:2055/RmiServer", obj);
This ran sucessfully without errors and my client was able to connect.
I hope this answer helps others with this error. Let me know if anyone needs any more detailed information.