Final cleanup work.

Relates to elastic#4879

This moves mustache back to being shaded - having guava (which is a needed
dependency of mustache) explicitly in the distribution files isn't an option:
Used by too many projects and thus likely to cause version conflicts downstream.

In addition this adds a rest test for the query templating feature.

pom.xml

@@ -506,6 +506,7 @@
                             <include>org.joda:joda-convert</include>
                             <include>io.netty:netty</include>
                             <include>com.ning:compress-lzf</include>
+                            <include>com.github.spullara.mustache.java:compiler</include>
                         </includes>
                     </artifactSet>
                     <relocations>

rest-api-spec/test/search/30_template_query_execution.yaml

@@ -0,0 +1,24 @@
+---
+"Template query":
+
+  - do:
+      index:
+        index:  test
+        type:   testtype
+        id:     1
+        body:   { "text": "value1" }
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        body: { "query": { "template": { "query": "{\"match_{{template}}\": {}}", "params" : { "template" : "all" } } } }
+
+  - match: { hits.total: 1 }
+
+
+  - do:
+      search:
+        body: { "query": { "template": { "query": {"match_{{template}}": {}}, "params" : { "template" : "all" } } } }
+
+  - match: { hits.total: 1 }

src/main/assemblies/common-bin.xml

@@ -9,8 +9,6 @@
                 <include>net.java.dev.jna:jna</include>
                 <include>com.spatial4j:spatial4j</include>
                 <include>com.vividsolutions:jts</include>
-                <include>com.github.spullara.mustache.java:compiler</include>
-                <include>com.google.guava:guava</include>
             </includes>
         </dependencySet>
         <dependencySet>

src/main/java/org/elasticsearch/script/mustache/MustacheScriptEngineService.java

@@ -99,9 +99,14 @@ public Object execute(Object template, Map<String, Object> vars) {
         ((Mustache) template).execute(writer, vars);
         try {
             writer.flush();
-            writer.close();
         } catch (IOException e) {
-            logger.error("Could not execute query template: ", e);
+            logger.error("Could not execute query template (failed to flush writer): ", e);
+        } finally {
+            try {
+                writer.close();
+            } catch (IOException e) {
+                logger.error("Could not execute query template (failed to close writer): ", e);
+            }
         }
         return result.bytes();
     }
@@ -169,9 +174,14 @@ public Object run() {
             ((Mustache) mustache).execute(writer, vars);
             try {
                 writer.flush();
-                writer.close();
             } catch (IOException e) {
-                logger.error("Could not execute query template: ", e);
+                logger.error("Could not execute query template (failed to flush writer): ", e);
+            } finally {
+                try {
+                    writer.close();
+                } catch (IOException e) {
+                    logger.error("Could not execute query template (failed to close writer): ", e);
+                }
             }
             return result.bytes();
         }