From a15b1b97d22d63fd21c888b576bd130db8680af7 Mon Sep 17 00:00:00 2001 From: Alexander Reelsen Date: Thu, 27 Sep 2018 09:40:15 +0200 Subject: [PATCH] Watcher: Reduce script cache churn by checking for mustache tags (#33978) Watcher is using a lot of so called TextTemplate fields in a watch definition, which can use mustache to insert the watch id for example. For the user it is non-obvious which field is just a string field or which field is a text template. This also means, that for every such field, we currently do a script compilation, even if the field does not contain any mustache syntax. This will lead to an increased script cache churn, because those compiled scripts (that only contain a string), will evict other scripts. On top of that, this also means that an unneeded compilation has happened, instead of returning that string immediately. The usages of mustache templating are in all of the actions (most of the time far more than one compilation) as well as most of the inputs. Especially when running a lot of watches in parallel, this will reduce execution times and help reuse of real scripts. --- .../common/text/TextTemplateEngine.java | 5 +++ .../common/text/TextTemplateTests.java | 43 +++++++++++++++++-- 2 files changed, 45 insertions(+), 3 deletions(-) diff --git a/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateEngine.java b/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateEngine.java index 7b87a9e87a542..d2159fd572f5d 100644 --- a/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateEngine.java +++ b/x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateEngine.java @@ -35,6 +35,11 @@ public String render(TextTemplate textTemplate, Map model) { String mediaType = compileParams(detectContentType(template)); template = trimContentType(textTemplate); + int indexStartMustacheExpression = template.indexOf("{{"); + if (indexStartMustacheExpression == -1) { + return template; + } + Map mergedModel = new HashMap<>(); if (textTemplate.getParams() != null) { mergedModel.putAll(textTemplate.getParams()); diff --git a/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateTests.java b/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateTests.java index 0e084af23e1fb..002d833c20913 100644 --- a/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateTests.java +++ b/x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/common/text/TextTemplateTests.java @@ -21,6 +21,7 @@ import java.util.Collections; import java.util.HashMap; +import java.util.Locale; import java.util.Map; import static java.util.Collections.singletonMap; @@ -31,7 +32,10 @@ import static org.hamcrest.Matchers.is; import static org.hamcrest.Matchers.notNullValue; import static org.hamcrest.Matchers.nullValue; +import static org.mockito.Matchers.any; import static org.mockito.Mockito.mock; +import static org.mockito.Mockito.verify; +import static org.mockito.Mockito.verifyZeroInteractions; import static org.mockito.Mockito.when; public class TextTemplateTests extends ESTestCase { @@ -47,7 +51,7 @@ public void init() throws Exception { } public void testRender() throws Exception { - String templateText = "_template"; + String templateText = "{{_template}}"; Map params = singletonMap("param_key", "param_val"); Map model = singletonMap("model_key", "model_val"); Map merged = new HashMap<>(params); @@ -72,7 +76,7 @@ public String execute() { } public void testRenderOverridingModel() throws Exception { - String templateText = "_template"; + String templateText = "{{_template}}"; Map params = singletonMap("key", "param_val"); Map model = singletonMap("key", "model_val"); ScriptType type = randomFrom(ScriptType.values()); @@ -94,7 +98,7 @@ public String execute() { } public void testRenderDefaults() throws Exception { - String templateText = "_template"; + String templateText = "{{_template}}"; Map model = singletonMap("key", "model_val"); TemplateScript.Factory compiledTemplate = templateParams -> @@ -113,6 +117,39 @@ public String execute() { assertThat(engine.render(template, model), is("rendered_text")); } + public void testDontInvokeScriptServiceOnNonMustacheText() { + assertNoCompilation("this is my text"); + assertScriptServiceInvoked("}}{{"); + assertScriptServiceInvoked("}}{{ctx.payload}}"); + } + + private void assertNoCompilation(String input) { + String output = engine.render(new TextTemplate(input), Collections.emptyMap()); + assertThat(input, is(output)); + verifyZeroInteractions(service); + } + + private void assertScriptServiceInvoked(final String input) { + ScriptService scriptService = mock(ScriptService.class); + TextTemplateEngine e = new TextTemplateEngine(Settings.EMPTY, scriptService); + + TemplateScript.Factory compiledTemplate = templateParams -> + new TemplateScript(templateParams) { + @Override + public String execute() { + return input.toUpperCase(Locale.ROOT); + } + }; + + when(scriptService.compile(new Script(ScriptType.INLINE, lang, input, + Collections.singletonMap("content_type", "text/plain"), Collections.emptyMap()), Watcher.SCRIPT_TEMPLATE_CONTEXT)) + .thenReturn(compiledTemplate); + + String output = e.render(new TextTemplate(input), Collections.emptyMap()); + verify(scriptService).compile(any(), any()); + assertThat(output, is(input.toUpperCase(Locale.ROOT))); + } + public void testParser() throws Exception { ScriptType type = randomScriptType(); TextTemplate template =