2408 Allow retries to be enabled on default Apache HTTP client

README.md

@@ -2278,6 +2278,7 @@ You can adjust configuration settings for the HTTP client used by Karate using t
 `abortSuiteOnFailure` | boolean | defaults to `false`, to not attempt to run any more tests upon a failure
 `ntlmAuth` | JSON | See [NTLM Authentication](#ntlm-authentication)
 `matchEachEmptyAllowed` | boolean | defaults to `false`, [`match each`](#match-each) by default expects the array to be non-empty, refer to [this issue](https://github.com/karatelabs/karate/issues/2364) to understand why you may want to over-ride this.
+`httpRetryEnabled` | boolean | defaults to `false`, retry when the http requests fails with an exception `org.apache.httpNoHttpResponseException`.  For details see [this issue](https://github.com/karatelabs/karate/issues/2408)
 
 Examples:
 ```cucumber

karate-core/src/main/java/com/intuit/karate/core/Config.java

@@ -117,6 +117,7 @@ public class Config {
 
     // ntlm authentication
     private boolean ntlmEnabled = false;
+    private boolean httpRetryEnabled = false;
     private String ntlmUsername;
     private String ntlmPassword;
     private String ntlmDomain;
@@ -383,6 +384,7 @@ public Config(Config parent) {
         imageComparisonOptions = parent.imageComparisonOptions;
         matchEachEmptyAllowed = parent.matchEachEmptyAllowed;
         ntlmEnabled = parent.ntlmEnabled;
+        httpRetryEnabled = parent.httpRetryEnabled;
         ntlmUsername = parent.ntlmUsername;
         ntlmPassword = parent.ntlmPassword;
         ntlmDomain = parent.ntlmDomain;
@@ -513,6 +515,12 @@ public boolean isPrintEnabled() {
         return printEnabled;
     }
 
+    public boolean isHttpRetryEnabled()
+    {
+        return httpRetryEnabled;
+    }
+
+
     public Map<String, Map<String, Object>> getCustomOptions() {
         return customOptions;
     }    
@@ -665,4 +673,8 @@ public void setNtlmWorkstation(String ntlmWorkstation) {
         this.ntlmWorkstation = ntlmWorkstation;
     }
 
+    public void setHttpRetryEnabled(boolean httpRetryEnabled)
+    {
+        this.httpRetryEnabled = httpRetryEnabled;
+    }
 }

karate-core/src/main/java/com/intuit/karate/http/ApacheHttpClient.java

@@ -137,7 +137,12 @@ public ApacheHttpClient(ScenarioEngine engine) {
 
     private void configure(Config config) {
         clientBuilder = HttpClientBuilder.create();
-        clientBuilder.disableAutomaticRetries();
+        if (config.isHttpRetryEnabled()) {
+            clientBuilder.setRetryHandler(new CustomHttpRequestRetryHandler(logger));
+        } else {
+            clientBuilder.disableAutomaticRetries();
+        }
+
         if (!config.isFollowRedirects()) {
             clientBuilder.disableRedirectHandling();
         } else { // support redirect on POST by default

karate-core/src/main/java/com/intuit/karate/http/CustomHttpRequestRetryHandler.java

@@ -0,0 +1,39 @@
+package com.intuit.karate.http;
+
+import java.io.IOException;
+
+import org.apache.http.NoHttpResponseException;
+import org.apache.http.client.HttpRequestRetryHandler;
+import org.apache.http.protocol.HttpContext;
+
+import com.intuit.karate.Logger;
+
+/**
+ * Calls will retry the call when the client throws a NoHttpResponseException.
+ * This is usually the case when there is steal connection. The retry cause that
+ * the connection is renewed and the second call will succeed.
+ */
+public class CustomHttpRequestRetryHandler implements HttpRequestRetryHandler
+{
+    private final Logger logger;
+
+    public CustomHttpRequestRetryHandler(Logger logger)
+    {
+        this.logger = logger;
+    }
+
+    @Override
+    public boolean retryRequest(IOException exception, int executionCount, HttpContext context)
+    {
+        if (exception instanceof NoHttpResponseException && executionCount < 1)
+        {
+            logger.error("Thrown an NoHttpResponseException retry...");
+            return true;
+        }
+        else
+        {
+            logger.error("Thrown an exception {}", exception.getMessage());
+            return false;
+        }
+    }
+}