Improve error and debug message

Polish code

relates #512

(cherry picked from commit b7d3e59)

docs/src/reference/asciidoc/core/configuration.adoc

@@ -299,8 +299,10 @@ WARN main mr.EsInputFormat - Field(s) [naem, adress] not found
 Whether to discovery the nodes within the {es} cluster or only to use the ones given in `es.nodes` for metadata queries. Note that this setting only applies during start-up; afterwards when reading and writing, {eh} uses the target index shards (and their hosting nodes) unless +es.nodes.client.only+ is enabled.
 
 `es.nodes.client.only` (default false)::
-Whether to use {es} {ref}/modules-node.html[client nodes] (or _load-balancers_). When enabled, {eh} will route _all_ its requests (after nodes discovery, if enabled) through the _client_ nodes within the cluster. Note this typically significantly reduces the node parallelism and thus it is disabled by default.
+Whether to use {es} {ref}/modules-node.html[client nodes] (or _load-balancers_). When enabled, {eh} will route _all_ its requests (after nodes discovery, if enabled) through the _client_ nodes within the cluster. Note this typically significantly reduces the node parallelism and thus it is disabled by default. Enabling it also
+disables `es.nodes.data.only` (since a client node is a non-data node).
 
+added[2.1.2]
 `es.nodes.data.only` (default true)::
 Whether to use {es} {ref}/modules-node.html[data nodes] only. When enabled, {eh} will route _all_ its requests (after nodes discovery, if enabled) through the _data_ nodes within the cluster. The purpose of this configuration setting is to avoid overwhelming non-data nodes as these tend to be "smaller" nodes. This is enabled by default.
 

mr/src/main/java/org/elasticsearch/hadoop/rest/InitializationUtils.java

@@ -77,9 +77,10 @@ public static void filterNonClientNodesIfNeeded(Settings settings, Log log) {
 
         RestClient bootstrap = new RestClient(settings);
         try {
+            String message = "Client-only routing specified but no client nodes with HTTP-enabled available";
             List<String> clientNodes = bootstrap.getHttpClientNodes();
             if (clientNodes.isEmpty()) {
-                throw new EsHadoopIllegalArgumentException("Client-only routing specified but no client nodes with HTTP-enabled were found in the cluster...");
+                throw new EsHadoopIllegalArgumentException(message);
             }
             if (log.isDebugEnabled()) {
                 log.debug(String.format("Found client nodes %s", clientNodes));
@@ -93,12 +94,12 @@ public static void filterNonClientNodesIfNeeded(Settings settings, Log log) {
             }
 
             if (ddNodes.isEmpty()) {
-                String message = "Client-only routing specified but no client nodes with HTTP-enabled available; ";
+
                 if (settings.getNodesDiscovery()) {
-                    message += String.format("looks like the client nodes discovered have been removed; is the cluster in a stable state? %s", clientNodes);
+                    message += String.format("; looks like the client nodes discovered have been removed; is the cluster in a stable state? %s", clientNodes);
                 }
                 else {
-                    message += String.format("node discovery is disabled and none of nodes specified fits the criterion %s", SettingsUtils.discoveredOrDeclaredNodes(settings));
+                    message += String.format("; node discovery is disabled and none of nodes specified fits the criterion %s", SettingsUtils.discoveredOrDeclaredNodes(settings));
                 }
                 throw new EsHadoopIllegalArgumentException(message);
             }
@@ -110,15 +111,16 @@ public static void filterNonClientNodesIfNeeded(Settings settings, Log log) {
     }
 
     public static void filterNonDataNodesIfNeeded(Settings settings, Log log) {
-        if (!settings.getNodesDataOnly()) {
+        if (!settings.getNodesDataOnly() || settings.getNodesClientOnly()) {
           return;
         }
 
         RestClient bootstrap = new RestClient(settings);
         try  {
+            String message = "No data nodes with HTTP-enabled available";
             List<String> dataNodes = bootstrap.getHttpDataNodes();
             if (dataNodes.isEmpty()) {
-                throw new EsHadoopIllegalArgumentException("Data node only routing specified but no data nodes with HTTP-enabled were found in the cluster...");
+                throw new EsHadoopIllegalArgumentException(message);
             }
             if (log.isDebugEnabled()) {
                 log.debug(String.format("Found data nodes %s", dataNodes));
@@ -132,12 +134,11 @@ public static void filterNonDataNodesIfNeeded(Settings settings, Log log) {
             }
 
             if (ddNodes.isEmpty()) {
-                String message = "Data node only routing specified but no data nodes with HTTP-enabled available; ";
                 if (settings.getNodesDiscovery()) {
-                    message += String.format("looks like the data nodes discovered have been removed; is the cluster in a stable state? %s", dataNodes);
+                    message += String.format("; looks like the data nodes discovered have been removed; is the cluster in a stable state? %s", dataNodes);
                 }
                 else {
-                    message += String.format("node discovery is disabled and none of nodes specified fits the criterion %s", SettingsUtils.discoveredOrDeclaredNodes(settings));
+                    message += String.format("; node discovery is disabled and none of nodes specified fits the criterion %s", SettingsUtils.discoveredOrDeclaredNodes(settings));
                 }
                 throw new EsHadoopIllegalArgumentException(message);
             }

mr/src/main/java/org/elasticsearch/hadoop/serialization/dto/Node.java

@@ -41,10 +41,7 @@ public Node(String id, Map<String, Object> data) {
         attributes = (Map<String, Object>) data.get("attributes");
         if (attributes != null) {
             isClient = ("false".equals(attributes.get("data")) && "false".equals(attributes.get("master")));
-        }
-
-        if (attributes != null) {
-            isData = !"false".equals((attributes.get("data")));
+            isData = !"false".equals(attributes.get("data"));
         }
 
         if (!hasHttp) {
@@ -117,7 +114,8 @@ else if (!id.equals(other.id))
     public String toString() {
         StringBuilder builder = new StringBuilder();
         builder.append("Node[id=").append(id).append(", name=").append(name).append(", ipAddress=").append(ipAddress)
-        .append(", httpPort=").append(httpPort).append("]");
+        .append(", httpPort=").append(httpPort).append(", isClient=").append(isClient).append(", isData=").append(isData)
+        .append("]");
         return builder.toString();
     }
 }