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io.airlift.discovery.client.HttpDiscoveryLookupClient Maven / Gradle / Ivy
/*
* Copyright 2010 Proofpoint, Inc.
*
* 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.airlift.discovery.client;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.io.ByteStreams;
import com.google.common.net.HttpHeaders;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.inject.Inject;
import io.airlift.http.client.CacheControl;
import io.airlift.http.client.HttpClient;
import io.airlift.http.client.HttpUriBuilder;
import io.airlift.http.client.Request;
import io.airlift.http.client.Request.Builder;
import io.airlift.http.client.RequestStats;
import io.airlift.http.client.Response;
import io.airlift.http.client.ResponseHandler;
import io.airlift.json.JsonCodec;
import io.airlift.node.NodeInfo;
import io.airlift.units.Duration;
import org.weakref.jmx.Flatten;
import org.weakref.jmx.Managed;
import java.io.IOException;
import java.net.URI;
import java.util.Optional;
import java.util.concurrent.CancellationException;
import java.util.concurrent.TimeUnit;
import java.util.function.Supplier;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static io.airlift.discovery.client.DiscoveryAnnouncementClient.DEFAULT_DELAY;
import static io.airlift.http.client.HttpStatus.NOT_MODIFIED;
import static io.airlift.http.client.HttpStatus.OK;
import static io.airlift.http.client.HttpUriBuilder.uriBuilderFrom;
import static io.airlift.http.client.Request.Builder.prepareGet;
import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
public class HttpDiscoveryLookupClient
implements DiscoveryLookupClient
{
private final String environment;
private final Supplier discoveryServiceURI;
private final NodeInfo nodeInfo;
private final JsonCodec serviceDescriptorsCodec;
private final HttpClient httpClient;
@Inject
public HttpDiscoveryLookupClient(
@ForDiscoveryClient Supplier discoveryServiceURI,
NodeInfo nodeInfo,
JsonCodec serviceDescriptorsCodec,
@ForDiscoveryClient HttpClient httpClient)
{
requireNonNull(discoveryServiceURI, "discoveryServiceURI is null");
requireNonNull(nodeInfo, "nodeInfo is null");
requireNonNull(serviceDescriptorsCodec, "serviceDescriptorsCodec is null");
requireNonNull(httpClient, "httpClient is null");
this.nodeInfo = nodeInfo;
this.environment = nodeInfo.getEnvironment();
this.discoveryServiceURI = discoveryServiceURI;
this.serviceDescriptorsCodec = serviceDescriptorsCodec;
this.httpClient = httpClient;
}
@Flatten
@Managed
public RequestStats getStats()
{
return httpClient.getStats();
}
@Override
public ListenableFuture getServices(String type)
{
requireNonNull(type, "type is null");
return lookup(type, null, null);
}
@Override
public ListenableFuture getServices(String type, String pool)
{
requireNonNull(type, "type is null");
requireNonNull(pool, "pool is null");
return lookup(type, pool, null);
}
@Override
public ListenableFuture refreshServices(ServiceDescriptors serviceDescriptors)
{
requireNonNull(serviceDescriptors, "serviceDescriptors is null");
return lookup(serviceDescriptors.getType(), serviceDescriptors.getPool(), serviceDescriptors);
}
private ListenableFuture lookup(final String type, final String pool, final ServiceDescriptors serviceDescriptors)
{
requireNonNull(type, "type is null");
URI uri = discoveryServiceURI.get();
if (uri == null) {
return immediateFailedFuture(new DiscoveryException("No discovery servers are available"));
}
Builder requestBuilder = prepareGet()
.setUri(createServiceLocation(uri, type, Optional.ofNullable(pool)))
.setHeader("User-Agent", nodeInfo.getNodeId());
if (serviceDescriptors != null && serviceDescriptors.getETag() != null) {
requestBuilder.setHeader(HttpHeaders.ETAG, serviceDescriptors.getETag());
}
return httpClient.executeAsync(requestBuilder.build(), new DiscoveryResponseHandler(format("Lookup of %s", type), uri)
{
@Override
public ServiceDescriptors handle(Request request, Response response)
{
Duration maxAge = extractMaxAge(response);
String eTag = response.getHeader(HttpHeaders.ETAG);
if (NOT_MODIFIED.code() == response.getStatusCode() && serviceDescriptors != null) {
return new ServiceDescriptors(serviceDescriptors, maxAge, eTag);
}
if (OK.code() != response.getStatusCode()) {
throw new DiscoveryException(format("Lookup of %s failed with status code %s", type, response.getStatusCode()));
}
byte[] json;
try {
json = ByteStreams.toByteArray(response.getInputStream());
}
catch (IOException e) {
throw new DiscoveryException(format("Lookup of %s failed", type), e);
}
ServiceDescriptorsRepresentation serviceDescriptorsRepresentation = serviceDescriptorsCodec.fromJson(json);
if (!environment.equals(serviceDescriptorsRepresentation.getEnvironment())) {
throw new DiscoveryException(format("Expected environment to be %s, but was %s", environment, serviceDescriptorsRepresentation.getEnvironment()));
}
return new ServiceDescriptors(
type,
pool,
serviceDescriptorsRepresentation.getServiceDescriptors(),
maxAge,
eTag);
}
});
}
private Duration extractMaxAge(Response response)
{
String header = response.getHeader(HttpHeaders.CACHE_CONTROL);
if (header != null) {
CacheControl cacheControl = CacheControl.valueOf(header);
if (cacheControl.getMaxAge() > 0) {
return new Duration(cacheControl.getMaxAge(), TimeUnit.SECONDS);
}
}
return DEFAULT_DELAY;
}
@VisibleForTesting
static URI createServiceLocation(URI baseUri, String type, Optional pool)
{
HttpUriBuilder builder = uriBuilderFrom(baseUri)
.appendPath("/v1/service")
.appendPath(type);
pool.ifPresent(builder::appendPath);
return builder.build();
}
private class DiscoveryResponseHandler
implements ResponseHandler
{
private final String name;
private final URI uri;
protected DiscoveryResponseHandler(String name, URI uri)
{
this.name = name;
this.uri = uri;
}
@Override
public T handle(Request request, Response response)
{
return null;
}
@Override
public final T handleException(Request request, Exception exception)
{
if (exception instanceof InterruptedException) {
throw new DiscoveryException(name + " was interrupted for " + uri);
}
if (exception instanceof CancellationException) {
throw new DiscoveryException(name + " was canceled for " + uri);
}
if (exception instanceof DiscoveryException) {
throw (DiscoveryException) exception;
}
throw new DiscoveryException(name + " failed for " + uri, exception);
}
}
}
