/
RetryingHelloWorldClient.java
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/
RetryingHelloWorldClient.java
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/*
* Copyright 2020 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 static java.nio.charset.StandardCharsets.UTF_8;
import com.google.gson.Gson;
import com.google.gson.stream.JsonReader;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.StatusRuntimeException;
import io.grpc.examples.helloworld.GreeterGrpc;
import io.grpc.examples.helloworld.HelloReply;
import io.grpc.examples.helloworld.HelloRequest;
import java.io.InputStreamReader;
import java.util.Map;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A client that requests a greeting from the {@link RetryingHelloWorldServer} with a retrying policy.
*/
public class RetryingHelloWorldClient {
static final String ENV_DISABLE_RETRYING = "DISABLE_RETRYING_IN_RETRYING_EXAMPLE";
private static final Logger logger = Logger.getLogger(RetryingHelloWorldClient.class.getName());
private final boolean enableRetries;
private final ManagedChannel channel;
private final GreeterGrpc.GreeterBlockingStub blockingStub;
private final AtomicInteger totalRpcs = new AtomicInteger();
private final AtomicInteger failedRpcs = new AtomicInteger();
protected Map<String, ?> getRetryingServiceConfig() {
return new Gson()
.fromJson(
new JsonReader(
new InputStreamReader(
RetryingHelloWorldClient.class.getResourceAsStream(
"retrying_service_config.json"),
UTF_8)),
Map.class);
}
/**
* Construct client connecting to HelloWorld server at {@code host:port}.
*/
public RetryingHelloWorldClient(String host, int port, boolean enableRetries) {
ManagedChannelBuilder<?> channelBuilder = ManagedChannelBuilder.forAddress(host, port)
// Channels are secure by default (via SSL/TLS). For the example we disable TLS to avoid
// needing certificates.
.usePlaintext();
if (enableRetries) {
Map<String, ?> serviceConfig = getRetryingServiceConfig();
logger.info("Client started with retrying configuration: " + serviceConfig);
channelBuilder.defaultServiceConfig(serviceConfig).enableRetry();
}
channel = channelBuilder.build();
blockingStub = GreeterGrpc.newBlockingStub(channel);
this.enableRetries = enableRetries;
}
public void shutdown() throws InterruptedException {
channel.shutdown().awaitTermination(60, TimeUnit.SECONDS);
}
/**
* Say hello to server in a blocking unary call.
*/
public void greet(String name) {
HelloRequest request = HelloRequest.newBuilder().setName(name).build();
HelloReply response = null;
StatusRuntimeException statusRuntimeException = null;
try {
response = blockingStub.sayHello(request);
} catch (StatusRuntimeException e) {
failedRpcs.incrementAndGet();
statusRuntimeException = e;
}
totalRpcs.incrementAndGet();
if (statusRuntimeException == null) {
logger.log(Level.INFO,"Greeting: {0}", new Object[]{response.getMessage()});
} else {
logger.log(Level.INFO,"RPC failed: {0}", new Object[]{statusRuntimeException.getStatus()});
}
}
private void printSummary() {
logger.log(
Level.INFO,
"\n\nTotal RPCs sent: {0}. Total RPCs failed: {1}\n",
new Object[]{
totalRpcs.get(), failedRpcs.get()});
if (enableRetries) {
logger.log(
Level.INFO,
"Retrying enabled. To disable retries, run the client with environment variable {0}=true.",
ENV_DISABLE_RETRYING);
} else {
logger.log(
Level.INFO,
"Retrying disabled. To enable retries, unset environment variable {0} and then run the client.",
ENV_DISABLE_RETRYING);
}
}
public static void main(String[] args) throws Exception {
boolean enableRetries = !Boolean.parseBoolean(System.getenv(ENV_DISABLE_RETRYING));
final RetryingHelloWorldClient client = new RetryingHelloWorldClient("localhost", 50051, enableRetries);
ForkJoinPool executor = new ForkJoinPool();
for (int i = 0; i < 50; i++) {
final String userId = "user" + i;
executor.execute(
new Runnable() {
@Override
public void run() {
client.greet(userId);
}
});
}
executor.awaitQuiescence(100, TimeUnit.SECONDS);
executor.shutdown();
client.printSummary();
client.shutdown();
}
}