First pass adding config hooks interface

Author: Crim

CHANGELOG.md

@@ -2,6 +2,10 @@
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## 3.1.3 (08/11/2021)
+- [Issue-55](https://github.com/SourceLabOrg/kafka-connect-client/issues/55) Create new HttpContext for every request.
+- 
+
 ## 3.1.2 (07/21/2021)
 
 - [Issue-54](https://github.com/SourceLabOrg/kafka-connect-client/issues/54) Resolution for issue-54

src/main/java/org/sourcelab/kafka/connect/apiclient/rest/DefaultHttpClientConfigHooks.java

@@ -0,0 +1,7 @@
+package org.sourcelab.kafka.connect.apiclient.rest;
+
+/**
+ * Default implementation makes no modifications.
+ */
+public class DefaultHttpClientConfigHooks implements HttpClientConfigHooks {
+}

src/main/java/org/sourcelab/kafka/connect/apiclient/rest/HttpClientConfigHooks.java

@@ -0,0 +1,116 @@
+package org.sourcelab.kafka.connect.apiclient.rest;
+
+import org.apache.http.client.AuthCache;
+import org.apache.http.client.CredentialsProvider;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.http.impl.client.BasicAuthCache;
+import org.apache.http.impl.client.BasicCredentialsProvider;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.sourcelab.kafka.connect.apiclient.Configuration;
+
+/**
+ * HttpClient configuration hooks.
+ *
+ * Provides an interface for modifying how the underlying HttpClient instance is created.
+ */
+public interface HttpClientConfigHooks {
+    /**
+     * Create HttpClientBuilder instance.
+     * @param configuration KafkaConnectClient configuration.
+     * @return HttpClientBuilder instance.
+     */
+    default HttpClientBuilder createHttpClientBuilder(final Configuration configuration) {
+        return HttpClientBuilder.create();
+    }
+
+    /**
+     * Create HttpsContextBuilder instance.
+     * @param configuration KafkaConnectClient configuration.
+     * @return HttpsContextBuilder instance.
+     */
+    default HttpsContextBuilder createHttpsContextBuilder(final Configuration configuration) {
+        return new HttpsContextBuilder(configuration);
+    }
+
+    /**
+     * Create RequestConfig.Builder instance.
+     * @param configuration KafkaConnectClient configuration.
+     * @return RequestConfig.Builder instance.
+     */
+    default RequestConfig.Builder createRequestConfigBuilder(final Configuration configuration) {
+        return RequestConfig.custom();
+    }
+
+    /**
+     * Create AuthCache instance.
+     * @param configuration KafkaConnectClient configuration.
+     * @return AuthCache instance.
+     */
+    default AuthCache createAuthCache(final Configuration configuration) {
+        return new BasicAuthCache();
+    }
+
+    /**
+     * Create CredentialsProvider instance.
+     * @param configuration KafkaConnectClient configuration.
+     * @return CredentialsProvider instance.
+     */
+    default CredentialsProvider createCredentialsProvider(final Configuration configuration) {
+        return new BasicCredentialsProvider();
+    }
+
+    /**
+     * Create HttpClientContext instance.
+     * @param configuration KafkaConnectClient configuration.
+     * @return HttpClientContext instance.
+     */
+    default HttpClientContext createHttpClientContext(final Configuration configuration) {
+        return HttpClientContext.create();
+    }
+
+    /**
+     * Ability to modify or replace the AuthCache instance after initial configuration has been performed on it.
+     * @param configuration KafkaConnectClient configuration.
+     * @return AuthCache instance.
+     */
+    default AuthCache modifyAuthCache(final Configuration configuration, final AuthCache authCache) {
+        return authCache;
+    }
+
+    /**
+     * Ability to modify or replace the CredentialsProvider instance after initial configuration has been performed on it.
+     * @param configuration KafkaConnectClient configuration.
+     * @return CredentialsProvider instance.
+     */
+    default CredentialsProvider modifyCredentialsProvider(final Configuration configuration, final CredentialsProvider credentialsProvider) {
+        return credentialsProvider;
+    }
+
+    /**
+     * Ability to modify or replace the RequestConfig.Builder instance after initial configuration has been performed on it.
+     * @param configuration KafkaConnectClient configuration.
+     * @return RequestConfig.Builder instance.
+     */
+    default RequestConfig.Builder modifyRequestConfig(final Configuration configuration, final RequestConfig.Builder builder) {
+        return builder;
+    }
+
+    /**
+     * Ability to modify or replace the HttpClientBuilder instance after initial configuration has been performed on it.
+     * @param configuration KafkaConnectClient configuration.
+     * @return HttpClientBuilder instance.
+     */
+    default HttpClientBuilder modifyHttpClientBuilder(final Configuration configuration, final HttpClientBuilder builder) {
+        return builder;
+    }
+
+    /**
+     * Ability to modify or replace the HttpClientContext instance after initial configuration has been performed on it.
+     * @param configuration KafkaConnectClient configuration.
+     * @return HttpClientContext instance.
+     */
+    default HttpClientContext modifyHttpClientContext(final Configuration configuration, final HttpClientContext context) {
+        return context;
+    }
+}

src/main/java/org/sourcelab/kafka/connect/apiclient/rest/HttpClientRestClient.java

@@ -96,10 +96,24 @@ public class HttpClientRestClient implements RestClient {
      */
     private CredentialsProvider credsProvider;
 
+    /**
+     * Provides an interface for modifying how the underlying HttpClient instance is created.
+     */
+    private final HttpClientConfigHooks configHooks;
+
     /**
      * Constructor.
      */
     public HttpClientRestClient() {
+        this(new DefaultHttpClientConfigHooks());
+    }
+
+    /**
+     * Constructor allowing for injecting configuration hooks.
+     * @param configHooks For hooking/overriding into how the underlying HttpClient is configured.
+     */
+    public HttpClientRestClient(final HttpClientConfigHooks configHooks) {
+        this.configHooks = configHooks;
     }
 
     /**
@@ -113,10 +127,10 @@ public void init(final Configuration configuration) {
         this.configuration = configuration;
 
         // Create https context builder utility.
-        final HttpsContextBuilder httpsContextBuilder = new HttpsContextBuilder(configuration);
+        final HttpsContextBuilder httpsContextBuilder = configHooks.createHttpsContextBuilder(configuration);
 
-        // Setup client builder
-        final HttpClientBuilder clientBuilder = createHttpClientBuilder();
+        // Create and setup client builder
+        HttpClientBuilder clientBuilder = configHooks.createHttpClientBuilder(configuration);
         clientBuilder
             // Define timeout
             .setConnectionTimeToLive(configuration.getConnectionTimeToLiveInSeconds(), TimeUnit.SECONDS)
@@ -125,15 +139,15 @@ public void init(final Configuration configuration) {
             .setSSLSocketFactory(httpsContextBuilder.createSslSocketFactory());
 
         // Define our RequestConfigBuilder
-        final RequestConfig.Builder requestConfigBuilder = RequestConfig.custom();
+        RequestConfig.Builder requestConfigBuilder = configHooks.createRequestConfigBuilder(configuration);
 
         requestConfigBuilder.setConnectTimeout(configuration.getRequestTimeoutInSeconds() * 1_000);
 
         // Define our Credentials Provider
-        credsProvider = new BasicCredentialsProvider();
+        credsProvider = configHooks.createCredentialsProvider(configuration);
 
         // Define our auth cache
-        authCache = new BasicAuthCache();
+        authCache = configHooks.createAuthCache(configuration);
 
         // If we have a configured proxy host
         if (configuration.getProxyHost() != null) {
@@ -186,13 +200,19 @@ public void init(final Configuration configuration) {
             }
         }
 
+        // Call Modify hooks
+        authCache = configHooks.modifyAuthCache(configuration, authCache);
+        credsProvider = configHooks.modifyCredentialsProvider(configuration, credsProvider);
+        requestConfigBuilder = configHooks.modifyRequestConfig(configuration, requestConfigBuilder);
+
         // Attach Credentials provider to client builder.
         clientBuilder.setDefaultCredentialsProvider(credsProvider);
 
         // Attach default request config
         clientBuilder.setDefaultRequestConfig(requestConfigBuilder.build());
 
         // build http client
+        clientBuilder = configHooks.modifyHttpClientBuilder(configuration, clientBuilder);
         httpClient = clientBuilder.build();
     }
 
@@ -407,12 +427,12 @@ private String constructApiUrl(final String endPoint) {
      */
     private HttpClientContext createHttpClientContext() {
         // Define our context
-        final HttpClientContext httpClientContext = HttpClientContext.create();
+        final HttpClientContext httpClientContext = configHooks.createHttpClientContext(configuration);
 
         // Configure context.
         httpClientContext.setAuthCache(authCache);
         httpClientContext.setCredentialsProvider(credsProvider);
 
-        return httpClientContext;
+        return configHooks.modifyHttpClientContext(configuration, httpClientContext);
     }
 }