fix multiple potential bugs, enhance logging data, set version to SNAPSHOT

Author: Dušan Markovič

README.md

@@ -15,7 +15,7 @@ JMeter ElasticSearch Backend Listener is a JMeter plugin enabling you to send te
 * Bulk requests
   * By making bulk requests, there are practically no impacts on the performance of the tests themselves. 
 * Filters
-  * Only send the samples you want by using Filters! Simply type them as follows in the appropriate field : ``filter1;filter2;filter3`` or ``sampleLabel_must_contain_this``.
+  * Only send the samples you want by using Filters! Simply type them as follows in the field ``es.sample.filter`` : ``filter1;filter2;filter3`` or ``sampleLabel_must_contain_this``.
 * Specific fields ```field1;field2;field3`
   * Specify fields that you want to send to ElasticSearch (possible fields below)
      * AllThreads
@@ -56,7 +56,7 @@ JMeter ElasticSearch Backend Listener is a JMeter plugin enabling you to send te
 <dependency>
   <groupId>io.github.delirius325</groupId>
   <artifactId>jmeter.backendlistener.elasticsearch</artifactId>
-  <version>2.6.10</version>
+  <version>2.6.10-SNAPSHOT</version>
 </dependency>
 ```
 

pom.xml

@@ -5,7 +5,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>io.github.delirius325</groupId>
 	<artifactId>jmeter.backendlistener.elasticsearch</artifactId>
-	<version>2.6.10</version>
+	<version>2.6.10-SNAPSHOT</version>
 	<packaging>jar</packaging>
 
 	<name>jmeter.backendlistener.elasticsearch</name>

src/main/java/io/github/delirius325/jmeter/backendlistener/elasticsearch/ElasticSearchMetric.java

@@ -155,18 +155,19 @@ private void addElapsedTime() {
      */
     private void addCustomFields(BackendListenerContext context) {
         Iterator<String> pluginParameters = context.getParameterNamesIterator();
+        String parameter;
         while (pluginParameters.hasNext()) {
             String parameterName = pluginParameters.next();
 
-            if (!parameterName.startsWith("es.") && !context.getParameter(parameterName).trim().equals("")) {
-                String parameter = context.getParameter(parameterName).trim();
+            if (!parameterName.startsWith("es.") && context.containsParameter(parameterName)
+                    && !"".equals(parameter = context.getParameter(parameterName).trim())) {
 
                 try {
                     addFilteredJSON(parameterName, Long.parseLong(parameter));
-                } catch (Exception e) {
+                } catch (NumberFormatException e) {
                     if (logger.isDebugEnabled())
-                        logger.debug("Cannot convert custom field to number");
-                    addFilteredJSON(parameterName, context.getParameter(parameterName).trim());
+                        logger.debug("Cannot convert custom field to number [name={}, value={}]]", parameterName, parameter);
+                    addFilteredJSON(parameterName, parameter);
                 }
             }
         }
@@ -217,7 +218,7 @@ private void parseHeadersAsJsonProps(boolean allReqHeaders, boolean allResHeader
 
                 // if not all res/req headers and header contains special X-tag
                 if (!allReqHeaders && !allResHeaders && header.length > 1) {
-                    if (header[0].startsWith("X-es-backend")) {
+                    if (header[0].startsWith("X-es-backend-")) {
                         this.json.put(header[0].replaceAll("X-es-backend-", "").trim(), header[1].trim());
                     }
                 }

src/main/java/io/github/delirius325/jmeter/backendlistener/elasticsearch/ElasticSearchMetricSender.java

@@ -104,7 +104,8 @@ public int getElasticSearchVersion() {
     	 try {
              Response response = this.client.performRequest(setAuthorizationHeader(request));
              if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK && logger.isErrorEnabled()) {
-                 logger.error("Unable to perform request to ElasticSearch engine", this.esIndex);
+                 logger.error("Unable to perform request to ElasticSearch engine for index {}. Response status: {}",
+                              this.esIndex, response.getStatusLine().toString());
              }else {
             	 String responseBody = EntityUtils.toString(response.getEntity());
      			 JSONObject elasticSearchConfig = new JSONObject(responseBody);
@@ -153,7 +154,10 @@ public void sendRequest(int elasticSearchVersionPrefix) {
             Response response = this.client.performRequest(setAuthorizationHeader(request));
 
             if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK && logger.isErrorEnabled()) {
-                logger.error("ElasticSearch Backend Listener failed to write results for index {}", this.esIndex);
+                logger.error("ElasticSearch Backend Listener failed to write results for index {}. Response status: {}",
+                             this.esIndex, response.getStatusLine().toString());
+            } else {
+                logger.debug("ElasticSearch Backend Listener has successfully written results for index {}", this.esIndex);
             }
         } catch (Exception e) {
             if (logger.isErrorEnabled()) {