Scripts: Convert template uses to return String instead of BytesReference (elastic/x-pack-elasticsearch#1279)

This is the xpack side of elastic/elasticsearch#24447. The one caveat is
there are a number of places within the xpack api that use
BytesReference to pass down to templates. These are convert to encode
into a BytesArray when necessary, so as not to require changing all of
those apis here at once, but they should all be convert to String as
well.

Original commit: elastic/x-pack-elasticsearch@8399b9d8c3

plugin/src/main/java/org/elasticsearch/xpack/common/text/TextTemplateEngine.java

@@ -57,7 +57,7 @@ public class TextTemplateEngine extends AbstractComponent {
         }
         Script script = new Script(textTemplate.getType(), "mustache", template, options, mergedModel);
         CompiledTemplate compiledTemplate = service.compileTemplate(script, Watcher.SCRIPT_CONTEXT);
-        return compiledTemplate.run(model).utf8ToString();
+        return compiledTemplate.run(model);
     }
 
     private String trimContentType(TextTemplate textTemplate) {

plugin/src/main/java/org/elasticsearch/xpack/security/authz/accesscontrol/SecurityIndexSearcherWrapper.java

@@ -134,9 +134,9 @@ public class SecurityIndexSearcherWrapper extends IndexSearcherWrapper {
                 BooleanQuery.Builder filter = new BooleanQuery.Builder();
                 for (BytesReference bytesReference : permissions.getQueries()) {
                     QueryShardContext queryShardContext = queryShardContextProvider.apply(shardId);
-                    bytesReference = evaluateTemplate(bytesReference);
+                    String templateResult = evaluateTemplate(bytesReference.utf8ToString());
-                    try (XContentParser parser = XContentFactory.xContent(bytesReference)
+                    try (XContentParser parser = XContentFactory.xContent(templateResult)
-                            .createParser(queryShardContext.getXContentRegistry(), bytesReference)) {
+                            .createParser(queryShardContext.getXContentRegistry(), templateResult)) {
                         QueryBuilder queryBuilder = queryShardContext.newParseContext(parser).parseInnerQueryBuilder();
                         verifyRoleQuery(queryBuilder);
                         failIfQueryUsesClient(scriptService, queryBuilder, queryShardContext);
@@ -244,7 +244,7 @@ public class SecurityIndexSearcherWrapper extends IndexSearcherWrapper {
         }
     }
 
-    BytesReference evaluateTemplate(BytesReference querySource) throws IOException {
+    String evaluateTemplate(String querySource) throws IOException {
         // EMPTY is safe here because we never use namedObject
         try (XContentParser parser = XContentFactory.xContent(querySource).createParser(NamedXContentRegistry.EMPTY, querySource)) {
             XContentParser.Token token = parser.nextToken();

plugin/src/main/java/org/elasticsearch/xpack/watcher/input/search/ExecutableSearchInput.java

@@ -9,6 +9,7 @@ import org.apache.logging.log4j.Logger;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.SearchType;
 import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
@@ -53,9 +54,9 @@ public class ExecutableSearchInput extends ExecutableInput<SearchInput, SearchIn
         WatcherSearchTemplateRequest request = null;
         try {
             Script template = input.getRequest().getOrCreateTemplate();
-            BytesReference renderedTemplate = searchTemplateService.renderTemplate(template, ctx, payload);
+            String renderedTemplate = searchTemplateService.renderTemplate(template, ctx, payload);
             // We need to make a copy, so that we don't modify the original instance that we keep around in a watch:
-            request = new WatcherSearchTemplateRequest(input.getRequest(), renderedTemplate);
+            request = new WatcherSearchTemplateRequest(input.getRequest(), new BytesArray(renderedTemplate));
             return doExecute(ctx, request);
         } catch (Exception e) {
             logger.error("failed to execute [{}] input for watch [{}], reason [{}]", TYPE, ctx.watch().id(), e.getMessage());

plugin/src/main/java/org/elasticsearch/xpack/watcher/support/search/WatcherSearchTemplateService.java

@@ -41,7 +41,7 @@ public class WatcherSearchTemplateService extends AbstractComponent {
         this.xContentRegistry = xContentRegistry;
     }
 
-    public BytesReference renderTemplate(Script source,
+    public String renderTemplate(Script source,
                                          WatchExecutionContext ctx,
                                          Payload payload) throws IOException {
         // Due the inconsistency with templates in ES 1.x, we maintain our own template format.

plugin/src/main/java/org/elasticsearch/xpack/watcher/transform/search/ExecutableSearchTransform.java

@@ -11,6 +11,7 @@ import org.apache.logging.log4j.util.Supplier;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.search.SearchType;
 import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.script.Script;
@@ -44,9 +45,9 @@ public class ExecutableSearchTransform extends ExecutableTransform<SearchTransfo
         WatcherSearchTemplateRequest request = null;
         try {
             Script template = transform.getRequest().getOrCreateTemplate();
-            BytesReference renderedTemplate = searchTemplateService.renderTemplate(template, ctx, payload);
+            String renderedTemplate = searchTemplateService.renderTemplate(template, ctx, payload);
             // We need to make a copy, so that we don't modify the original instance that we keep around in a watch:
-            request = new WatcherSearchTemplateRequest(transform.getRequest(), renderedTemplate);
+            request = new WatcherSearchTemplateRequest(transform.getRequest(), new BytesArray(renderedTemplate));
             SearchResponse resp = client.search(searchTemplateService.toSearchRequest(request), timeout);
             return new SearchTransform.Result(request, new Payload.XContent(resp));
         } catch (Exception e) {

plugin/src/test/java/org/elasticsearch/xpack/common/text/TextTemplateTests.java

@@ -57,7 +57,7 @@ public class TextTemplateTests extends ESTestCase {
         merged = unmodifiableMap(merged);
         ScriptType type = randomFrom(ScriptType.values());
 
-        CompiledTemplate compiledTemplate = templateParams -> new BytesArray("rendered_text");
+        CompiledTemplate compiledTemplate = templateParams -> "rendered_text";
         when(service.compileTemplate(new Script(type, lang, templateText,
                 type == ScriptType.INLINE ? Collections.singletonMap("content_type", "text/plain") : null,
                 merged), Watcher.SCRIPT_CONTEXT)).thenReturn(compiledTemplate);
@@ -72,7 +72,7 @@ public class TextTemplateTests extends ESTestCase {
         Map<String, Object> model = singletonMap("key", "model_val");
         ScriptType type = randomFrom(ScriptType.values());
 
-        CompiledTemplate compiledTemplate = templateParams -> new BytesArray("rendered_text");
+        CompiledTemplate compiledTemplate = templateParams -> "rendered_text";
         when(service.compileTemplate(new Script(type, lang, templateText,
                 type == ScriptType.INLINE ? Collections.singletonMap("content_type", "text/plain") : null,
                 model), Watcher.SCRIPT_CONTEXT)).thenReturn(compiledTemplate);
@@ -85,7 +85,7 @@ public class TextTemplateTests extends ESTestCase {
         String templateText = "_template";
         Map<String, Object> model = singletonMap("key", "model_val");
 
-        CompiledTemplate compiledTemplate = templateParams -> new BytesArray("rendered_text");
+        CompiledTemplate compiledTemplate = templateParams -> "rendered_text";
         when(service.compileTemplate(new Script(ScriptType.INLINE, lang, templateText,
                 Collections.singletonMap("content_type", "text/plain"), model), Watcher.SCRIPT_CONTEXT))
                 .thenReturn(compiledTemplate);

plugin/src/test/java/org/elasticsearch/xpack/security/authz/accesscontrol/SecurityIndexSearcherWrapperUnitTests.java

@@ -465,7 +465,7 @@ public class SecurityIndexSearcherWrapperUnitTests extends ESTestCase {
         Script script = new Script(ScriptType.INLINE, "mustache", query, Collections.singletonMap("custom", "value"));
         builder = jsonBuilder().startObject().field("template");
         script.toXContent(builder, ToXContent.EMPTY_PARAMS);
-        BytesReference querySource = builder.endObject().bytes();
+        String querySource = builder.endObject().string();
 
         securityIndexSearcherWrapper.evaluateTemplate(querySource);
         ArgumentCaptor<Script> argument = ArgumentCaptor.forClass(Script.class);
@@ -492,8 +492,8 @@ public class SecurityIndexSearcherWrapperUnitTests extends ESTestCase {
         securityIndexSearcherWrapper =
                 new SecurityIndexSearcherWrapper(indexSettings, null, null, threadContext, licenseState, scriptService);
         XContentBuilder builder = jsonBuilder();
-        BytesReference querySource =  new TermQueryBuilder("field", "value").toXContent(builder, ToXContent.EMPTY_PARAMS).bytes();
+        String querySource =  new TermQueryBuilder("field", "value").toXContent(builder, ToXContent.EMPTY_PARAMS).string();
-        BytesReference result = securityIndexSearcherWrapper.evaluateTemplate(querySource);
+        String result = securityIndexSearcherWrapper.evaluateTemplate(querySource);
         assertThat(result, sameInstance(querySource));
         verifyZeroInteractions(scriptService);
     }