Talk about the parameters of JerseyEurekaHttpClient

  springcloud

Order

This paper mainly studies the parameters of JerseyEurekaHttpClient

JerseyEurekaHttpClientFactory

eureka-client-1.8.8-sources.jar! /com/netflix/discovery/shared/transport/jersey/JerseyEurekaHttpClientFactory.java

        private JerseyEurekaHttpClientFactory buildLegacy(Map<String, String> additionalHeaders, boolean systemSSL) {
            EurekaJerseyClientBuilder clientBuilder = new EurekaJerseyClientBuilder()
                    .withClientName(clientName)
                    .withUserAgent("Java-EurekaClient")
                    .withConnectionTimeout(connectionTimeout)
                    .withReadTimeout(readTimeout)
                    .withMaxConnectionsPerHost(maxConnectionsPerHost)
                    .withMaxTotalConnections(maxTotalConnections)
                    .withConnectionIdleTimeout((int) connectionIdleTimeout)
                    .withEncoderWrapper(encoderWrapper)
                    .withDecoderWrapper(decoderWrapper);

            if (systemSSL) {
                clientBuilder.withSystemSSLConfiguration();
            } else if (sslContext != null) {
                clientBuilder.withCustomSSL(sslContext);
            }
            
            if (hostnameVerifier != null) {
                clientBuilder.withHostnameVerifier(hostnameVerifier);
            }

            EurekaJerseyClient jerseyClient = clientBuilder.build();
            ApacheHttpClient4 discoveryApacheClient = jerseyClient.getClient();
            addFilters(discoveryApacheClient);

            return new JerseyEurekaHttpClientFactory(jerseyClient, additionalHeaders);
        }

When build was seen during the opening here, the parameters connectionTimeout, readTimeout, maxConnectionsPerHost, maxTotalConnections, connectionIdleTimeout were specified.

EurekaJerseyClientImpl

eureka-client-1.8.8-sources.jar! /com/netflix/discovery/shared/transport/jersey/EurekaJerseyClientImpl.java

    public EurekaJerseyClientImpl(int connectionTimeout, int readTimeout, final int connectionIdleTimeout,
                                  ClientConfig clientConfig) {
        try {
            jerseyClientConfig = clientConfig;
            apacheHttpClient = ApacheHttpClient4.create(jerseyClientConfig);
            HttpParams params = apacheHttpClient.getClientHandler().getHttpClient().getParams();

            HttpConnectionParams.setConnectionTimeout(params, connectionTimeout);
            HttpConnectionParams.setSoTimeout(params, readTimeout);

            this.apacheHttpClientConnectionCleaner = new ApacheHttpClientConnectionCleaner(apacheHttpClient, connectionIdleTimeout);
        } catch (Throwable e) {
            throw new RuntimeException("Cannot create Jersey client", e);
        }
    }
    
    public EurekaJerseyClient build() {
            MyDefaultApacheHttpClient4Config config = new MyDefaultApacheHttpClient4Config();
            try {
                return new EurekaJerseyClientImpl(connectionTimeout, readTimeout, connectionIdleTimeout, config);
            } catch (Throwable e) {
                throw new RuntimeException("Cannot create Jersey client ", e);
            }
        }

        class MyDefaultApacheHttpClient4Config extends DefaultApacheHttpClient4Config {
            MyDefaultApacheHttpClient4Config() {
                MonitoredConnectionManager cm;

                if (systemSSL) {
                    cm = createSystemSslCM();
                } else if (sslContext != null || hostnameVerifier != null || trustStoreFileName != null) {
                    cm = createCustomSslCM();
                } else {
                    cm = createDefaultSslCM();
                }

                if (proxyHost != null) {
                    addProxyConfiguration(cm);
                }

                DiscoveryJerseyProvider discoveryJerseyProvider = new DiscoveryJerseyProvider(encoderWrapper, decoderWrapper);
                getSingletons().add(discoveryJerseyProvider);

                // Common properties to all clients
                cm.setDefaultMaxPerRoute(maxConnectionsPerHost);
                cm.setMaxTotal(maxTotalConnections);
                getProperties().put(ApacheHttpClient4Config.PROPERTY_CONNECTION_MANAGER, cm);

                String fullUserAgentName = (userAgent == null ? clientName : userAgent) + "/v" + buildVersion();
                getProperties().put(CoreProtocolPNames.USER_AGENT, fullUserAgentName);

                // To pin a client to specific server in case redirect happens, we handle redirects directly
                // (see DiscoveryClient.makeRemoteCall methods).
                getProperties().put(PROPERTY_FOLLOW_REDIRECTS, Boolean.FALSE);
                getProperties().put(ClientPNames.HANDLE_REDIRECTS, Boolean.FALSE);
            }
            //......
        }            

It can be seen that maxConnectionsPerHost and maxTotalConnections are configured in MonitoredConnectionManager;; ConnectionTimeout, readTimeout, connectionIdleTimeout are configured on HttpConnectionParams of apache http client.

Parameter configuration

eureka-client-1.8.8-sources.jar! /com/netflix/discovery/shared/transport/EurekaClientFactoryBuilder.java

    public B withClientConfig(EurekaClientConfig clientConfig) {
        withClientAccept(EurekaAccept.fromString(clientConfig.getClientDataAccept()));
        withAllowRedirect(clientConfig.allowRedirects());
        withConnectionTimeout(clientConfig.getEurekaServerConnectTimeoutSeconds() * 1000);
        withReadTimeout(clientConfig.getEurekaServerReadTimeoutSeconds() * 1000);
        withMaxConnectionsPerHost(clientConfig.getEurekaServerTotalConnectionsPerHost());
        withMaxTotalConnections(clientConfig.getEurekaServerTotalConnections());
        withConnectionIdleTimeout(clientConfig.getEurekaConnectionIdleTimeoutSeconds() * 1000);
        withEncoder(clientConfig.getEncoderName());
        return withDecoder(clientConfig.getDecoderName(), clientConfig.getClientDataAccept());
    }

You can see that it is read from EurekaClientConfig and its mapping relation is as follows:

Attribute Configuration Default value explain
connectionTimeout eureka.client.eureka-server-connect-timeout-seconds 5 Indicates how long to wait (in seconds) before a connection to eureka server needs to timeout. Note that the connections in the client are pooled by org.apache.http.client.HttpClient and thi s setting affects the actual connection creation and also the wait time to get the connection from the pool.
readTimeout eureka.client.eureka-server-read-timeout-seconds 8 Indicates how long to wait (in seconds) before a read from eureka server needs to timeout.
maxConnectionsPerHost eureka.client.eureka-server-total-connections-per-host 50 Gets the total number of connections that is allowed from eureka client to a eureka server host.
maxTotalConnections eureka.client.eureka-server-total-connections 200 Gets the total number of connections that is allowed from eureka client to all eureka servers.
connectionIdleTimeout eureka.client.eureka-connection-idle-timeout-seconds 30 Indicates how much time (in seconds) that the HTTP connections to eureka server can stay idle before it can be closed. In the AWS environment, it is recommended that the values is 30 seconds or less, since the firewall cleans up the connection information after a few mins leaving the connection hanging in limbo

Summary

It can be accessed through eureka-server-connect-timeout-seconds, eureka-server-read-timeout-seconds, eureka-server-total-connections-per-host, eureka-server-total-connections, The eureka-connection-idle-timeout-seconds parameter configures and manages the http connection that eureka client requests eureka server.

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