We have a use case where, we have many RPC defined in different-different .proto files , and we generate a java based grpc stub code by using google's protobuf-java & protoc-gen-grpc-java as gradle plugin.
The requirement is we want to generate a new Service which flips the request, response and add stream to new flipped rpc.
So for example :
service Greeter {
// Sends a greeting
rpc SayHello (HelloRequest) returns (HelloReply) {}
}
// The request message containing the user's name.
message HelloRequest {
string name = 1;
}
// The response message containing the greetings
message HelloReply {
string message = 1;
}
to be converted to like
service Greeter {
// Sends a greeting
rpc SayHello (HelloRequest) returns (HelloReply) {}
rpc SayHelloStreaming (stream HelloReply) returns (stream HelloRequest) {}
}
// The request message containing the user's name.
message HelloRequest {
string name = 1;
}
// The response message containing the greetings
message HelloReply {
string message = 1;
}
In java generated code I should be having 2 services for each original service. We just want the final java generated code to be having 2 services, the parser may/may not update original .proto files.
Is this customization possible with current protoc ? Can we extend the plugin and write ours -> Can someone please give some pointers.
Your question is unclear to me.
Revising proto files is a fundamental requirement of gRPC.
The Java tutorial on https://grpc.io includes an example of adding a method to a service. In part, this is because adding|removing|updating methods|messages|fields is a common behavior.
NOTE To clarify nomenclature, in your example, you're proposing adding a method to an existing service (definition). If you consider the proto as defining an API, this represents a non-breaking change. See Versioning gRPC services for a good overview. Existing clients will continue to work (they are only aware of SayHello) while new clients will be aware of SayHelloStreaming too.
Related
I have a gRPC service simmilar to below
// The greeting service definition.
service Greeter {
// Sends a greeting
rpc SayHello (HelloRequest) returns (HelloReply) {}
}
// The request message containing the user's name.
message HelloRequest {
string name = 1;
}
// The response message containing the greetings
message HelloReply {
string message = 1;
}
I need the client to maintain a long living gRPC connection to the server so that if the server goes down, the client can reconnect and issue SayHello() again.
Based on my understanding there are a few options:
Pass in a statsHandler to grpc.Dial and add retry logic in HandleConn()
Add a new ClientStreaming API that maybe sends a message every few seconds. Check for server side stream close errors and implement retry logic.
Not sure if there is a recommended way for my use case and would appreciate any help.
I have a microservices based application and wish to create a service that captures all Fault events with their message payloads (as json) and stores them in a database for later analysis and potential resubmission. I have created a Fault consumer and can capture the Fault but am unable to generically extract the message payload as json.
public Task Consume(ConsumeContext<Fault> context)
{
if (context is PipeContext pipeContext)
{
var result = pipeContext.TryGetPayload(out ConsumeContext<Fault> payload2);
var serCont = context.SerializerContext;
}
Console.WriteLine($"A message faulted:{context.Message.FaultedMessageId} " +
$"{context.Message.Exceptions} " +
$"{context.ConversationId}"
);
return Task.CompletedTask;
}
I can see the full details I want in the context.SerializerContext._message but this is unaccessable.
context.SerializerContext._message
I saw you comment for a similar question:
If you did want to later get the actual fault message, you could use
consumeContext.TryGetMessage<Fault>(out var faultContext) and if it
was present you'd get it back.
I don't have "T" from every service and therefore want to handle all Faults a JSON.
Is there a way I can capture the full Fault with the message, ideally as json, without having access to every T across my system?
I am on MassTransit 8.
Thanks
If you have the message type (T), you can use TryGetMessage<Fault<T>> and it will return the message type deserialized.
If you don't, or if you want to deal with the JSON in a message directly, using V8 you can get the actual JsonElement from the deserializer and navigate the JSON yourself:
var jsonElement = context.TryGetMessage<JsonElement>()
Previous answer, but for Newtonsoft: https://stackoverflow.com/a/46779547/1882
I am implementing a simple client-server grpc-c++ based application. In the Hello rpc, I am taking the request and sending the fields of another message called SeverInfo as response. The problem is I exactly don't know how to send this ServerInfo data to a client from server side. We basically use set_fieldname(ex: set_name) for general datatypes to send the data but how should we send this serverInfo data to HelloResponse and then to HelloRequest. Can somebody please help me??
Below I am attaching the proto file.
syntax = "proto3";
package sample;
service Sample {
rpc Hello(HelloRequest) returns (HelloReply){}
}
message HelloRequest {
string name = 1;
}
message HelloReply {
ServerInfo sinfo = 1;
}
message ServerInfo {
string name = 1;
string os = 2;
}
you can define another rpc in your service definitions like
service Sample {
rpc Hello(HelloRequest) returns (HelloReply){}
rpc GetServerInfo(HelloRequest) returns (ServerInfo){}
}
would that work for you?
Here is the answer that worked for me. Thank you.
ServerInfo* serverinfo=new ServerInfo();
serverinfo->set_name("");
serverinfo->set_os("");
HelloReply* rep;
rep->set_allocated_server(serverinfo);
I have a java spring integration project that is receving emails through the below code:
ClassPathXmlApplicationContext ac =
new ClassPathXmlApplicationContext(
"/integration/gmail-imap-idle-config.xml");
DirectChannel inputChannel = ac.getBean("receiveChannel", DirectChannel.class);
inputChannel.subscribe(message -> {
org.springframework.messaging.Message<MimeMailMessage> received =
(org.springframework.messaging.Message<MimeMailMessage>) message;
log.info("content" + message);
List<String> sentences = null;
try {
} catch (Exception e) {
}
I get the email, and I can get the subject, but I can never actually extract the message body. How do I do this?
Thank you!
You have to use this option on the channel adapter:
simple-content="true"
See its description:
When 'true', messages produced by the source will be rendered by 'MimeMessage.getContent()'
which is usually just the body for a simple text email. When false (default) the content
is rendered by the 'getContent()' method on the actual message returned by the underlying
javamail implementation.
For example, an IMAP message is rendered with some message headers.
This attribute is provided so that users can enable the previous behavior, which just
rendered the body.
But still it is doubtful, since I see in case of GMail message it is never simple. The content is a MimeMultipart and we need to read its parts to get access to the real body.
So, this is how you should change your code as well:
log.info("content" + ((MimeMultipart) ((MimeMessage) message.getPayload()).getContent()).getBodyPart(0).getContent());
I'm new to ZeroMQ (and to networking in general), and have a question about using ZeroMQ in a setup where multiple clients connect to a single server. My situation is as follows:
--1 server
--multiple clients
--Clients send messages to server: I've already figured out how to do this part.
--Server sends messages to a specific client: This is the part I'm having trouble with. When certain events get handled on the server, the server will need to send a message to a specific client -- not all clients. In other words, the server will need to be able to choose which client to send a given message to.
Right now, this is my server code:
using (NetMQContext ctx = NetMQContext.Create())
{
using (var server = ctx.CreateResponseSocket())
{
server.Bind(#"tcp://127.0.0.1:5555");
while (true)
{
string fromClientMessage = server.ReceiveString();
Console.WriteLine("From Client: {0}", fromClientMessage);
server.Send("ack"); // There is no overload for the 'Send'
method that takes an IP address as an argument!
}
}
}
I have a feeling that the problem is that my design is wrong, and that the ResponseSocket type isn't meant to be used in the way that I want to use it. Since I'm new to this, any advice is very much appreciated!
when using the Response socket you always replying to the client that sent you the message. So the Request-Response socket types together are just simple request response.
To more complicated scenarios you probably want to use Dealer-Router.
With router the first frame of each message is the routing id (the identity of the client that sent you the message)
so your example with router will look like:
using (NetMQContext ctx = NetMQContext.Create())
{
using (var server = ctx.CreateRouterSocket())
{
server.Bind(#"tcp://127.0.0.1:5555");
while (true)
{
byte[] routingId = server.Receive();
string fromClientMessage = server.ReceiveString();
Console.WriteLine("From Client: {0}", fromClientMessage);
server.SendMore(routingId).Send("ack");
}
}
}
I also suggest to read the zeromq guide, it will probably answer most of your questions.