Add HTTP error logger

src/main/java/com/github/rishabh9/riko/upstox/common/ServiceGenerator.java

@@ -29,6 +29,7 @@
 import com.github.rishabh9.riko.upstox.common.converters.NumberStringDeserializer;
 import com.github.rishabh9.riko.upstox.common.converters.NumberStringSerializer;
 import com.github.rishabh9.riko.upstox.common.interceptors.AuthenticationInterceptor;
+import com.github.rishabh9.riko.upstox.common.interceptors.HttpErrorLoggingInterceptor;
 import com.github.rishabh9.riko.upstox.common.models.AuthHeaders;
 import com.google.common.base.Strings;
 import com.google.gson.Gson;
@@ -169,13 +170,18 @@ public <S> S createService(@Nonnull final Class<S> serviceClass,
         httpClient.interceptors().clear(); // Fix StackOverFlowError
 
         enableAuthentication(headers);
+        enableHttpErrorLogging();
         if (log.isDebugEnabled()) {
             enableHttpLogging();
         }
         log.debug("Creating service with authorization headers");
         return retrofit.create(Objects.requireNonNull(serviceClass));
     }
 
+    private void enableHttpErrorLogging() {
+        addInterceptor(new HttpErrorLoggingInterceptor());
+    }
+
     private void enableAuthentication(final AuthHeaders headers) {
 
         if (null != headers

src/main/java/com/github/rishabh9/riko/upstox/common/interceptors/HttpErrorLoggingInterceptor.java

@@ -0,0 +1,57 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Rishabh Joshi
+ *
+ * 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 com.github.rishabh9.riko.upstox.common.interceptors;
+
+import okhttp3.Interceptor;
+import okhttp3.Request;
+import okhttp3.Response;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.io.IOException;
+
+/**
+ * Logs every response of every request that wasn't successful.
+ * That is, it logs, every response with status code not in the range [200..300).
+ */
+public class HttpErrorLoggingInterceptor implements Interceptor {
+
+    private static final Logger log = LogManager.getLogger(HttpErrorLoggingInterceptor.class);
+
+    @Override
+    public Response intercept(Chain chain) throws IOException {
+        Request request = chain.request();
+        okhttp3.Response response = chain.proceed(request);
+
+        if (!response.isSuccessful()) {
+            final String message =
+                    "ATTENTION! API endpoint: " + request.url().toString() +
+                            " returned Status Code: " + response.code() +
+                            " with Body: " + response.peekBody(1024L).string();
+            log.error(message);
+        }
+        return response;
+    }
+}