Add Bloom filters to the Cloud SQL PremiumList schema (#306)

* Add Bloom filters to the Cloud SQL PremiumList schema

They are slightly different from the existing Bloom filters stored in Datastore
in that they now use an ASCII String encoding rather than the more generic
CharSequence, and there is no maximum size (whereas we previously had to live
within the 1 MB max entity size for Datastore).

core/src/main/java/google/registry/persistence/BloomFilterConverter.java

@@ -0,0 +1,59 @@
+// Copyright 2019 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed 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 google.registry.persistence;
+
+import static com.google.common.base.Charsets.US_ASCII;
+import static com.google.common.hash.Funnels.stringFunnel;
+
+import com.google.common.hash.BloomFilter;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import javax.annotation.Nullable;
+import javax.persistence.AttributeConverter;
+import javax.persistence.Converter;
+
+/** JPA converter for ASCII String {@link BloomFilter}s. */
+@Converter(autoApply = true)
+public class BloomFilterConverter implements AttributeConverter<BloomFilter<String>, byte[]> {
+
+  @Override
+  @Nullable
+  public byte[] convertToDatabaseColumn(@Nullable BloomFilter<String> entity) {
+    if (entity == null) {
+      return null;
+    }
+    ByteArrayOutputStream bos = new ByteArrayOutputStream();
+    try {
+      entity.writeTo(bos);
+    } catch (IOException e) {
+      throw new UncheckedIOException("Error saving Bloom filter data", e);
+    }
+    return bos.toByteArray();
+  }
+
+  @Override
+  @Nullable
+  public BloomFilter<String> convertToEntityAttribute(@Nullable byte[] columnValue) {
+    if (columnValue == null) {
+      return null;
+    }
+    try {
+      return BloomFilter.readFrom(new ByteArrayInputStream(columnValue), stringFunnel(US_ASCII));
+    } catch (IOException e) {
+      throw new UncheckedIOException("Error loading Bloom filter data", e);
+    }
+  }
+}

core/src/main/java/google/registry/schema/tld/PremiumList.java

@@ -14,8 +14,12 @@
 
 package google.registry.schema.tld;
 
+import static com.google.common.base.Charsets.US_ASCII;
 import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.hash.Funnels.stringFunnel;
 
+import com.google.common.collect.ImmutableMap;
+import com.google.common.hash.BloomFilter;
 import google.registry.model.CreateAutoTimestamp;
 import java.math.BigDecimal;
 import java.util.Map;
@@ -67,11 +71,16 @@ public class PremiumList {
   @Column(name = "price", nullable = false)
   private Map<String, BigDecimal> labelsToPrices;
 
+  @Column(nullable = false)
+  private BloomFilter<String> bloomFilter;
+
   private PremiumList(String name, CurrencyUnit currency, Map<String, BigDecimal> labelsToPrices) {
-    // TODO(mcilwain): Generate the Bloom filter and set it here.
     this.name = name;
     this.currency = currency;
     this.labelsToPrices = labelsToPrices;
+    // ASCII is used for the charset because all premium list domain labels are stored punycoded.
+    this.bloomFilter = BloomFilter.create(stringFunnel(US_ASCII), labelsToPrices.size());
+    labelsToPrices.keySet().forEach(this.bloomFilter::put);
   }
 
   // Hibernate requires this default constructor.
@@ -101,7 +110,18 @@ public class PremiumList {
   }
 
   /** Returns a {@link Map} of domain labels to prices. */
-  public Map<String, BigDecimal> getLabelsToPrices() {
-    return labelsToPrices;
+  public ImmutableMap<String, BigDecimal> getLabelsToPrices() {
+    return ImmutableMap.copyOf(labelsToPrices);
+  }
+
+  /**
+   * Returns a Bloom filter to determine whether a label might be premium, or is definitely not.
+   *
+   * <p>If the domain label might be premium, then the next step is to check for the existence of a
+   * corresponding row in the PremiumListEntry table. Otherwise, we know for sure it's not premium,
+   * and no DB load is required.
+   */
+  public BloomFilter<String> getBloomFilter() {
+    return bloomFilter;
   }
 }

core/src/main/resources/META-INF/persistence.xml

@@ -33,6 +33,7 @@
     <class>google.registry.model.eppcommon.Trid</class>
 
     <!-- Customized type converters -->
+    <class>google.registry.persistence.BloomFilterConverter</class>
     <class>google.registry.persistence.CreateAutoTimestampConverter</class>
     <class>google.registry.persistence.UpdateAutoTimestampConverter</class>
     <class>google.registry.persistence.ZonedDateTimeConverter</class>