http client config hooks interface

CHANGELOG.md

@@ -2,6 +2,24 @@
 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.
+- [PR-59](https://github.com/SourceLabOrg/kafka-connect-client/pull/59) Adds supportted way to modify the underlying configuration of HttpClient via HttpClientConfigHooks interface.
+
+Usage of these hooks would look like:
+
+```java
+// Directly create underlying RestClient and pass your HttpClientConfigHooks implementation.
+final RestClient restClient = new HttpClientRestClient(new HttpClientConfigHooks {
+    // Override methods as needed to modify behavior.
+});
+
+// Create KafkaConnectClient, passing configuration and RestClient implementation
+final KafkaConnectClient client = new KafkaConnectClient(configuration, restClient);
+
+// Use client as normal...
+```
+
 ## 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 +1,24 @@
+/**
+ * Copyright 2018, 2019, 2020, 2021 SourceLab.org https://github.com/SourceLabOrg/kafka-connect-client
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit
+ * persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+ * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+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 +1,145 @@
+/**
+ * Copyright 2018, 2019, 2020, 2021 SourceLab.org https://github.com/SourceLabOrg/kafka-connect-client
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit
+ * persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+ * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+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.
+ *
+ * Usage of this would look like:
+ *
+ * final RestClient restClient = new HttpClientRestClient(new HttpClientConfigHooks {
+ *    // Override methods as needed to modify behavior.
+ * });
+ *
+ * // Create client, passing configuration and RestClient implementation
+ * final KafkaConnectClient client = new KafkaConnectClient(configuration, restClient);
+ *
+ * // Use client as normal...
+ *
+ */
+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

@@ -35,8 +35,6 @@
 import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.auth.BasicScheme;
-import org.apache.http.impl.client.BasicAuthCache;
-import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.message.BasicHeader;
@@ -60,6 +58,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 /**
@@ -96,10 +95,24 @@ 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 +126,13 @@ 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 = Objects.requireNonNull(
+            configHooks.createHttpClientBuilder(configuration),
+            "HttpClientConfigHook::createHttpClientBuilder() must return non-null instance."
+        );
         clientBuilder
             // Define timeout
             .setConnectionTimeToLive(configuration.getConnectionTimeToLiveInSeconds(), TimeUnit.SECONDS)
@@ -125,15 +141,24 @@ public void init(final Configuration configuration) {
             .setSSLSocketFactory(httpsContextBuilder.createSslSocketFactory());
 
         // Define our RequestConfigBuilder
-        final RequestConfig.Builder requestConfigBuilder = RequestConfig.custom();
+        RequestConfig.Builder requestConfigBuilder = Objects.requireNonNull(
+            configHooks.createRequestConfigBuilder(configuration),
+            "HttpClientConfigHook::createRequestConfigBuilder() must return non-null instance."
+        );
 
         requestConfigBuilder.setConnectTimeout(configuration.getRequestTimeoutInSeconds() * 1_000);
 
         // Define our Credentials Provider
-        credsProvider = new BasicCredentialsProvider();
+        credsProvider = Objects.requireNonNull(
+            configHooks.createCredentialsProvider(configuration),
+            "HttpClientConfigHook::createCredentialsProvider() must return non-null instance."
+        );
 
         // Define our auth cache
-        authCache = new BasicAuthCache();
+        authCache = Objects.requireNonNull(
+            configHooks.createAuthCache(configuration),
+            "HttpClientConfigHook::createAuthCache() must return non-null instance."
+        );
 
         // If we have a configured proxy host
         if (configuration.getProxyHost() != null) {
@@ -186,13 +211,31 @@ public void init(final Configuration configuration) {
             }
         }
 
+        // Call Modify hooks
+        authCache = Objects.requireNonNull(
+            configHooks.modifyAuthCache(configuration, authCache),
+            "HttpClientConfigHook::modifyAuthCache() must return non-null instance."
+        );
+        credsProvider = Objects.requireNonNull(
+            configHooks.modifyCredentialsProvider(configuration, credsProvider),
+            "HttpClientConfigHook::modifyCredentialsProvider() must return non-null instance."
+        );
+        requestConfigBuilder = Objects.requireNonNull(
+            configHooks.modifyRequestConfig(configuration, requestConfigBuilder),
+            "HttpClientConfigHook::modifyRequestConfig() must return non-null instance."
+        );
+
         // Attach Credentials provider to client builder.
         clientBuilder.setDefaultCredentialsProvider(credsProvider);
 
         // Attach default request config
         clientBuilder.setDefaultRequestConfig(requestConfigBuilder.build());
 
         // build http client
+        clientBuilder = Objects.requireNonNull(
+            configHooks.modifyHttpClientBuilder(configuration, clientBuilder),
+            "HttpClientConfigHook::modifyHttpClientBuilder() must return non-null instance."
+        );
         httpClient = clientBuilder.build();
     }
 
@@ -407,12 +450,12 @@ 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);
     }
 }