#19725 debounces graphql cache evictions and syncronizes the cache re…

…build

dotCMS/src/main/java/com/dotcms/concurrent/Debouncer.java

@@ -0,0 +1,64 @@
+package com.dotcms.concurrent;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import com.dotmarketing.util.Logger;
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * Usage:
+ * 
+ * final Debouncer debouncer = new Debouncer(); 
+ * debouncer.debounce("myRunnableKey", new Runnable() {()->{runnable..} , 300, TimeUnit.MILLISECONDS);
+ */
+public class Debouncer {
+
+    @VisibleForTesting
+    Debouncer(Long runCount) {
+        this.runCount = runCount;
+    }
+
+    public Debouncer() {
+
+    }
+
+    @VisibleForTesting
+    Long runCount = null;
+
+    private final ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
+    private final ConcurrentHashMap<String, Future<?>> delayedMap = new ConcurrentHashMap<>();
+
+    /**
+     * Debounces {@code callable} by {@code delay}, i.e., schedules it to be executed after
+     * {@code delay}, or cancels its execution if the method is called with the same key within the
+     * {@code delay} again.
+     */
+    public void debounce(final String key, final Runnable runnable, final long delay, final TimeUnit unit) {
+        final Future<?> prev = delayedMap.put(key, scheduler.schedule(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    if (null != runCount) {
+                        ++runCount;
+                        Logger.info(Debouncer.class, () -> "Debouncer has run : " + runCount + " times");
+                    }
+                    Logger.info(Debouncer.class, () -> "Debouncer Runnning : " + key + " after " + delay + " " + unit);
+
+                    runnable.run();
+                } finally {
+                    delayedMap.remove(key);
+                }
+            }
+        }, delay, unit));
+        if (prev != null) {
+            prev.cancel(true);
+        }
+    }
+
+    public void shutdown() {
+        scheduler.shutdownNow();
+    }
+}

dotCMS/src/main/java/com/dotcms/graphql/business/GraphqlAPIImpl.java

@@ -6,7 +6,7 @@
 import static graphql.schema.GraphQLList.list;
 import static graphql.schema.GraphQLNonNull.nonNull;
 import static graphql.schema.GraphQLObjectType.newObject;
-
+import com.dotcms.concurrent.Debouncer;
 import com.dotcms.graphql.InterfaceType;
 import com.dotcms.graphql.datafetcher.ContentletDataFetcher;
 import com.dotcms.util.LogTime;
@@ -31,6 +31,7 @@
 import java.util.List;
 import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.TimeUnit;
 
 public class GraphqlAPIImpl implements GraphqlAPI {
 
@@ -71,23 +72,43 @@ public GraphqlAPIImpl() {
     public GraphQLSchema getSchema() throws DotDataException {
         Optional<GraphQLSchema> schema = schemaCache.getSchema();
 
-        if(!schema.isPresent()) {
+        if(schema.isPresent()) {
+            return schema.get();
+        }
+        synchronized (this) {
+            schema = schemaCache.getSchema();
+            if(schema.isPresent()) {
+                return schema.get();
+            }
             final GraphQLSchema generatedSchema = generateSchema();
             schemaCache.putSchema(generatedSchema);
             return generatedSchema;
-        } else {
-            return schema.get();
         }
+
     }
 
+    final Debouncer debouncer = new Debouncer();
+
+
     /**
      * Nullifies the schema so it is regenerated next time it is fetched
+     * This method is debounced for 30 seconds to prevent overloading when
+     * content types are saved.
      */
     @Override
     public void invalidateSchema() {
-        schemaCache.removeSchema();
+
+        debouncer.debounce("invalidateGraphSchema", new Runnable() {
+            @Override
+            public void run() {
+                schemaCache.removeSchema();
+            }
+        }, Config.getIntProperty("GRAPHQL_SCHEMA_DEBOUNCE_DELAY", 30), TimeUnit.SECONDS);;
+
+
     }
 
+
     @Override
     public void printSchema() {
         if (Config.getBooleanProperty("GRAPHQL_PRINT_SCHEMA", false)) {

dotCMS/src/test/java/com/dotcms/concurrent/DebouncerTest.java

@@ -0,0 +1,38 @@
+package com.dotcms.concurrent;
+
+import static org.junit.Assert.*;
+import java.util.concurrent.TimeUnit;
+import org.junit.Test;
+import com.dotmarketing.util.Logger;
+
+public class DebouncerTest {
+
+
+
+
+
+    @Test
+    public void test() throws InterruptedException {
+        Debouncer debouncer = new Debouncer(0L);
+
+        // debounce for 10 seconds
+        debouncer.debounce("testingKey", ()->{Logger.info("DebouncerTest","running debouncer test" );}, 5, TimeUnit.SECONDS);
+        debouncer.debounce("testingKey", ()->{Logger.info("DebouncerTest","running debouncer test" );}, 5, TimeUnit.SECONDS);
+        debouncer.debounce("testingKey", ()->{Logger.info("DebouncerTest","running debouncer test" );}, 5, TimeUnit.SECONDS);
+        debouncer.debounce("testingKey", ()->{Logger.info("DebouncerTest","running debouncer test" );}, 5, TimeUnit.SECONDS);
+        debouncer.debounce("testingKey", ()->{Logger.info("DebouncerTest","running debouncer test" );}, 5, TimeUnit.SECONDS);
+        debouncer.debounce("testingKey", ()->{Logger.info("DebouncerTest","running debouncer test" );}, 5, TimeUnit.SECONDS);
+        debouncer.debounce("testingKey", ()->{Logger.info("DebouncerTest","running debouncer test" );}, 5, TimeUnit.SECONDS);
+
+        Thread.sleep(7*1000);
+
+
+        assertTrue("assert that we have only run once", debouncer.runCount==1);
+
+
+
+
+
+    }
+
+}