[INGEST] Lazy load the geoip databases.

Load the geoip database the first time a pipeline gets created that has a geoip processor.
This saves memory (measured ~150MB for the city db) in cases when the plugin is installed, but not used.

plugins/ingest-geoip/src/main/java/org/elasticsearch/ingest/geoip/DatabaseReaderLazyLoader.java

@@ -0,0 +1,62 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.ingest.geoip;
+
+import com.maxmind.geoip2.DatabaseReader;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.util.IOUtils;
+import org.apache.lucene.util.SetOnce;
+import org.elasticsearch.common.CheckedSupplier;
+import org.elasticsearch.common.logging.Loggers;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+/**
+ * Facilitates lazy loading of the database reader, so that when the geoip plugin is installed, but not used,
+ * no memory is being wasted on the database reader.
+ */
+final class DatabaseReaderLazyLoader implements Closeable {
+
+    private static final Logger LOGGER = Loggers.getLogger(DatabaseReaderLazyLoader.class);
+
+    private final String databaseFileName;
+    private final CheckedSupplier<DatabaseReader, IOException> loader;
+    // package protected for testing only:
+    final SetOnce<DatabaseReader> databaseReader;
+
+    DatabaseReaderLazyLoader(String databaseFileName, CheckedSupplier<DatabaseReader, IOException> loader) {
+        this.databaseFileName = databaseFileName;
+        this.loader = loader;
+        this.databaseReader = new SetOnce<>();
+    }
+
+    synchronized DatabaseReader get() throws IOException {
+        if (databaseReader.get() == null) {
+            databaseReader.set(loader.get());
+            LOGGER.debug("Loaded [{}] geoip database", databaseFileName);
+        }
+        return databaseReader.get();
+    }
+
+    @Override
+    public synchronized void close() throws IOException {
+        IOUtils.close(databaseReader.get());
+    }
+}

plugins/ingest-geoip/src/main/java/org/elasticsearch/ingest/geoip/GeoIpProcessor.java

@@ -19,19 +19,6 @@
 
 package org.elasticsearch.ingest.geoip;
 
-import java.io.IOException;
-import java.net.InetAddress;
-import java.security.AccessController;
-import java.security.PrivilegedAction;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.EnumSet;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
-import java.util.Set;
-
 import com.maxmind.geoip2.DatabaseReader;
 import com.maxmind.geoip2.exception.AddressNotFoundException;
 import com.maxmind.geoip2.model.CityResponse;
@@ -49,6 +36,19 @@ import org.elasticsearch.ingest.AbstractProcessor;
 import org.elasticsearch.ingest.IngestDocument;
 import org.elasticsearch.ingest.Processor;
 
+import java.io.IOException;
+import java.net.InetAddress;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+
 import static org.elasticsearch.ingest.ConfigurationUtils.newConfigurationException;
 import static org.elasticsearch.ingest.ConfigurationUtils.readBooleanProperty;
 import static org.elasticsearch.ingest.ConfigurationUtils.readOptionalList;
@@ -264,9 +264,9 @@ public final class GeoIpProcessor extends AbstractProcessor {
         );
         static final Set<Property> DEFAULT_COUNTRY_PROPERTIES = EnumSet.of(Property.CONTINENT_NAME, Property.COUNTRY_ISO_CODE);
 
-        private final Map<String, DatabaseReader> databaseReaders;
+        private final Map<String, DatabaseReaderLazyLoader> databaseReaders;
 
-        public Factory(Map<String, DatabaseReader> databaseReaders) {
+        public Factory(Map<String, DatabaseReaderLazyLoader> databaseReaders) {
             this.databaseReaders = databaseReaders;
         }
 
@@ -279,12 +279,13 @@ public final class GeoIpProcessor extends AbstractProcessor {
             List<String> propertyNames = readOptionalList(TYPE, processorTag, config, "properties");
             boolean ignoreMissing = readBooleanProperty(TYPE, processorTag, config, "ignore_missing", false);
 
-            DatabaseReader databaseReader = databaseReaders.get(databaseFile);
+            DatabaseReaderLazyLoader lazyLoader = databaseReaders.get(databaseFile);
-            if (databaseReader == null) {
+            if (lazyLoader == null) {
                 throw newConfigurationException(TYPE, processorTag,
                     "database_file", "database file [" + databaseFile + "] doesn't exist");
             }
 
+            DatabaseReader databaseReader = lazyLoader.get();
             String databaseType = databaseReader.getMetadata().getDatabaseType();
 
             final Set<Property> properties;

plugins/ingest-geoip/src/main/java/org/elasticsearch/ingest/geoip/IngestGeoIpPlugin.java

@@ -19,6 +19,15 @@
 
 package org.elasticsearch.ingest.geoip;
 
+import com.maxmind.db.NoCache;
+import com.maxmind.db.NodeCache;
+import com.maxmind.geoip2.DatabaseReader;
+import org.apache.lucene.util.IOUtils;
+import org.elasticsearch.common.settings.Setting;
+import org.elasticsearch.ingest.Processor;
+import org.elasticsearch.plugins.IngestPlugin;
+import org.elasticsearch.plugins.Plugin;
+
 import java.io.Closeable;
 import java.io.IOException;
 import java.io.InputStream;
@@ -35,20 +44,11 @@ import java.util.Map;
 import java.util.stream.Stream;
 import java.util.zip.GZIPInputStream;
 
-import com.maxmind.db.NoCache;
-import com.maxmind.db.NodeCache;
-import com.maxmind.geoip2.DatabaseReader;
-import org.apache.lucene.util.IOUtils;
-import org.elasticsearch.common.settings.Setting;
-import org.elasticsearch.ingest.Processor;
-import org.elasticsearch.plugins.IngestPlugin;
-import org.elasticsearch.plugins.Plugin;
-
 public class IngestGeoIpPlugin extends Plugin implements IngestPlugin, Closeable {
     public static final Setting<Long> CACHE_SIZE =
         Setting.longSetting("ingest.geoip.cache_size", 1000, 0, Setting.Property.NodeScope);
 
-    private Map<String, DatabaseReader> databaseReaders;
+    private Map<String, DatabaseReaderLazyLoader> databaseReaders;
 
     @Override
     public List<Setting<?>> getSettings() {
@@ -76,12 +76,12 @@ public class IngestGeoIpPlugin extends Plugin implements IngestPlugin, Closeable
         return Collections.singletonMap(GeoIpProcessor.TYPE, new GeoIpProcessor.Factory(databaseReaders));
     }
 
-    static Map<String, DatabaseReader> loadDatabaseReaders(Path geoIpConfigDirectory, NodeCache cache) throws IOException {
+    static Map<String, DatabaseReaderLazyLoader> loadDatabaseReaders(Path geoIpConfigDirectory, NodeCache cache) throws IOException {
         if (Files.exists(geoIpConfigDirectory) == false && Files.isDirectory(geoIpConfigDirectory)) {
             throw new IllegalStateException("the geoip directory [" + geoIpConfigDirectory  + "] containing databases doesn't exist");
         }
 
-        Map<String, DatabaseReader> databaseReaders = new HashMap<>();
+        Map<String, DatabaseReaderLazyLoader> databaseReaders = new HashMap<>();
         try (Stream<Path> databaseFiles = Files.list(geoIpConfigDirectory)) {
             PathMatcher pathMatcher = geoIpConfigDirectory.getFileSystem().getPathMatcher("glob:**.mmdb.gz");
             // Use iterator instead of forEach otherwise IOException needs to be caught twice...
@@ -89,10 +89,13 @@ public class IngestGeoIpPlugin extends Plugin implements IngestPlugin, Closeable
             while (iterator.hasNext()) {
                 Path databasePath = iterator.next();
                 if (Files.isRegularFile(databasePath) && pathMatcher.matches(databasePath)) {
-                    try (InputStream inputStream = new GZIPInputStream(Files.newInputStream(databasePath, StandardOpenOption.READ))) {
+                    String databaseFileName = databasePath.getFileName().toString();
-                        databaseReaders.put(databasePath.getFileName().toString(),
+                    DatabaseReaderLazyLoader holder = new DatabaseReaderLazyLoader(databaseFileName, () -> {
-                            new DatabaseReader.Builder(inputStream).withCache(cache).build());
+                        try (InputStream inputStream = new GZIPInputStream(Files.newInputStream(databasePath, StandardOpenOption.READ))) {
-                    }
+                            return new DatabaseReader.Builder(inputStream).withCache(cache).build();
+                        }
+                    });
+                    databaseReaders.put(databaseFileName, holder);
                 }
             }
         }

plugins/ingest-geoip/src/test/java/org/elasticsearch/ingest/geoip/GeoIpProcessorFactoryTests.java

@@ -22,7 +22,6 @@ package org.elasticsearch.ingest.geoip;
 import com.carrotsearch.randomizedtesting.generators.RandomPicks;
 import com.maxmind.db.NoCache;
 import com.maxmind.db.NodeCache;
-import com.maxmind.geoip2.DatabaseReader;
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.Randomness;
 import org.elasticsearch.test.ESTestCase;
@@ -48,7 +47,7 @@ import static org.hamcrest.Matchers.sameInstance;
 
 public class GeoIpProcessorFactoryTests extends ESTestCase {
 
-    private static Map<String, DatabaseReader> databaseReaders;
+    private static Map<String, DatabaseReaderLazyLoader> databaseReaders;
 
     @BeforeClass
     public static void loadDatabaseReaders() throws IOException {
@@ -66,7 +65,7 @@ public class GeoIpProcessorFactoryTests extends ESTestCase {
 
     @AfterClass
     public static void closeDatabaseReaders() throws IOException {
-        for (DatabaseReader reader : databaseReaders.values()) {
+        for (DatabaseReaderLazyLoader reader : databaseReaders.values()) {
             reader.close();
         }
         databaseReaders = null;
@@ -222,4 +221,37 @@ public class GeoIpProcessorFactoryTests extends ESTestCase {
             assertThat(e.getMessage(), equalTo("[properties] property isn't a list, but of type [java.lang.String]"));
         }
     }
+
+    public void testLazyLoading() throws Exception {
+        Path configDir = createTempDir();
+        Path geoIpConfigDir = configDir.resolve("ingest-geoip");
+        Files.createDirectories(geoIpConfigDir);
+        Files.copy(new ByteArrayInputStream(StreamsUtils.copyToBytesFromClasspath("/GeoLite2-City.mmdb.gz")),
+            geoIpConfigDir.resolve("GeoLite2-City.mmdb.gz"));
+        Files.copy(new ByteArrayInputStream(StreamsUtils.copyToBytesFromClasspath("/GeoLite2-Country.mmdb.gz")),
+            geoIpConfigDir.resolve("GeoLite2-Country.mmdb.gz"));
+
+        // Loading another database reader instances, because otherwise we can't test lazy loading as the the
+        // database readers used at class level are reused between tests. (we want to keep that otherwise running this
+        // test will take roughly 4 times more time)
+        Map<String, DatabaseReaderLazyLoader> databaseReaders =
+            IngestGeoIpPlugin.loadDatabaseReaders(geoIpConfigDir, NoCache.getInstance());
+        GeoIpProcessor.Factory factory = new GeoIpProcessor.Factory(databaseReaders);
+        for (DatabaseReaderLazyLoader lazyLoader : databaseReaders.values()) {
+            assertNull(lazyLoader.databaseReader.get());
+        }
+
+        Map<String, Object> config = new HashMap<>();
+        config.put("field", "_field");
+        config.put("database_file", "GeoLite2-City.mmdb.gz");
+        factory.create(null, "_tag", config);
+        config = new HashMap<>();
+        config.put("field", "_field");
+        config.put("database_file", "GeoLite2-Country.mmdb.gz");
+        factory.create(null, "_tag", config);
+
+        for (DatabaseReaderLazyLoader lazyLoader : databaseReaders.values()) {
+            assertNotNull(lazyLoader.databaseReader.get());
+        }
+    }
 }