forked from grpc/grpc-java
/
RetryingHelloWorldServer.java
111 lines (98 loc) · 3.78 KB
/
RetryingHelloWorldServer.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
/*
* Copyright 2019 The gRPC Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.grpc.examples.retrying;
import io.grpc.*;
import java.text.DecimalFormat;
import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;
import io.grpc.examples.helloworld.GreeterGrpc;
import io.grpc.examples.helloworld.HelloReply;
import io.grpc.examples.helloworld.HelloRequest;
import io.grpc.stub.StreamObserver;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;
/**
* A HelloWorld server that responds to requests with UNAVAILABLE with a given percentage.
*/
public class RetryingHelloWorldServer {
private static final Logger logger = Logger.getLogger(RetryingHelloWorldServer.class.getName());
private static final float unavailablePercentage = 0.5F;
private static Random random = new Random();
private Server server;
private void start() throws IOException {
/* The port on which the server should run */
int port = 50051;
server = ServerBuilder.forPort(port)
.addService(new GreeterImpl())
.build()
.start();
logger.info("Server started, listening on " + port);
DecimalFormat df = new DecimalFormat("#%");
logger.info("Responding as UNAVAILABLE to " + df.format(unavailablePercentage) + " requests");
Runtime.getRuntime().addShutdownHook(new Thread() {
@Override
public void run() {
// Use stderr here since the logger may have been reset by its JVM shutdown hook.
System.err.println("*** shutting down gRPC server since JVM is shutting down");
try {
RetryingHelloWorldServer.this.stop();
} catch (InterruptedException e) {
e.printStackTrace(System.err);
}
System.err.println("*** server shut down");
}
});
}
private void stop() throws InterruptedException {
if (server != null) {
server.shutdown().awaitTermination(30, TimeUnit.SECONDS);
}
}
/**
* Await termination on the main thread since the grpc library uses daemon threads.
*/
private void blockUntilShutdown() throws InterruptedException {
if (server != null) {
server.awaitTermination();
}
}
/**
* Main launches the server from the command line.
*/
public static void main(String[] args) throws IOException, InterruptedException {
final RetryingHelloWorldServer server = new RetryingHelloWorldServer();
server.start();
server.blockUntilShutdown();
}
static class GreeterImpl extends GreeterGrpc.GreeterImplBase {
AtomicInteger retryCounter = new AtomicInteger(0);
@Override
public void sayHello(HelloRequest request, StreamObserver<HelloReply> responseObserver) {
int count = retryCounter.incrementAndGet();
if (random.nextFloat() < unavailablePercentage) {
logger.info("Returning stubbed UNAVAILABLE error. count: " + count);
responseObserver.onError(Status.UNAVAILABLE
.withDescription("Greeter temporarily unavailable...").asRuntimeException());
} else {
logger.info("Returning successful Hello response, count: " + count);
HelloReply reply = HelloReply.newBuilder().setMessage("Hello " + request.getName()).build();
responseObserver.onNext(reply);
responseObserver.onCompleted();
}
}
}
}