fix injection failure of StorageLocationSelectorStrategy objects

docs/configuration/index.md

@@ -1409,7 +1409,7 @@ These Historical configurations can be defined in the `historical/runtime.proper
 |Property|Description|Default|
 |--------|-----------|-------|
 |`druid.segmentCache.locations`|Segments assigned to a Historical process are first stored on the local file system (in a disk cache) and then served by the Historical process. These locations define where that local cache resides. This value cannot be NULL or EMPTY. Here is an example `druid.segmentCache.locations=[{"path": "/mnt/druidSegments", "maxSize": "10k", "freeSpacePercent": 1.0}]`. "freeSpacePercent" is optional, if provided then enforces that much of free disk partition space while storing segments. But, it depends on File.getTotalSpace() and File.getFreeSpace() methods, so enable if only if they work for your File System.| none |
-|`druid.segmentCache.locationSelectorStrategy`|The strategy used to select a location from the configured `druid.segmentCache.locations` for segment distribution. Possible values are `leastBytesUsed`, `roundRobin`, `random`, or `mostAvailableSize`. |leastBytesUsed|
+|`druid.segmentCache.locationSelector.strategy`|The strategy used to select a location from the configured `druid.segmentCache.locations` for segment distribution. Possible values are `leastBytesUsed`, `roundRobin`, `random`, or `mostAvailableSize`. |leastBytesUsed|
 |`druid.segmentCache.deleteOnRemove`|Delete segment files from cache once a process is no longer serving a segment.|true|
 |`druid.segmentCache.dropSegmentDelayMillis`|How long a process delays before completely dropping segment.|30000 (30 seconds)|
 |`druid.segmentCache.infoDir`|Historical processes keep track of the segments they are serving so that when the process is restarted they can reload the same segments without waiting for the Coordinator to reassign. This path defines where this metadata is kept. Directory will be created if needed.|${first_location}/info_dir|
@@ -1421,7 +1421,7 @@ These Historical configurations can be defined in the `historical/runtime.proper
 
 In `druid.segmentCache.locations`, *freeSpacePercent* was added because *maxSize* setting is only a theoretical limit and assumes that much space will always be available for storing segments. In case of any druid bug leading to unaccounted segment files left alone on disk or some other process writing stuff to disk, This check can start failing segment loading early before filling up the disk completely and leaving the host usable otherwise.
 
-In `druid.segmentCache.locationSelectorStrategy`, one of leastBytesUsed, roundRobin, random, or mostAvailableSize could be specified to represent the strategy to distribute segments across multiple segment cache locations.
+In `druid.segmentCache.locationSelector.strategy`, one of `leastBytesUsed`, `roundRobin`, `random`, or `mostAvailableSize` could be specified to represent the strategy to distribute segments across multiple segment cache locations.
 
 |Strategy|Description|
 |--------|-----------|

licenses.yaml

@@ -231,6 +231,7 @@ libraries:
   - com.fasterxml.jackson.jaxrs: jackson-jaxrs-json-provider
   - com.fasterxml.jackson.jaxrs: jackson-jaxrs-smile-provider
   - com.fasterxml.jackson.module: jackson-module-jaxb-annotations
+  - com.fasterxml.jackson.module: jackson-module-guice
 notice: |
   # Jackson JSON processor
 
@@ -4126,16 +4127,6 @@ libraries:
 
 ---
 
-name: "Jackson Module: Guice"
-license_category: binary
-module: java-core
-license_name: Apache License version 2.0
-version: 2.6.7
-libraries:
-  - com.fasterxml.jackson.module: jackson-module-guice
-
----
-
 name: Google APIs Client Library For Java
 license_category: binary
 module: java-core

server/pom.xml

@@ -315,6 +315,10 @@
             <groupId>io.timeandspace</groupId>
             <artifactId>cron-scheduler</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.module</groupId>
+            <artifactId>jackson-module-guice</artifactId>
+        </dependency>
 
         <!-- Tests -->
         <dependency>

server/src/main/java/org/apache/druid/guice/StorageNodeModule.java

@@ -33,11 +33,14 @@
 import org.apache.druid.query.DruidProcessingConfig;
 import org.apache.druid.segment.column.ColumnConfig;
 import org.apache.druid.segment.loading.SegmentLoaderConfig;
+import org.apache.druid.segment.loading.StorageLocation;
+import org.apache.druid.segment.loading.StorageLocationSelectorStrategy;
 import org.apache.druid.server.DruidNode;
 import org.apache.druid.server.coordination.DruidServerMetadata;
 import org.apache.druid.server.coordination.ServerType;
 
 import javax.annotation.Nullable;
+import java.util.List;
 
 /**
  */
@@ -52,6 +55,7 @@ public void configure(Binder binder)
   {
     JsonConfigProvider.bind(binder, "druid.server", DruidServerConfig.class);
     JsonConfigProvider.bind(binder, "druid.segmentCache", SegmentLoaderConfig.class);
+    bindLocationSelectorStrategy(binder);
 
     binder.bind(ServerTypeConfig.class).toProvider(Providers.of(null));
     binder.bind(ColumnConfig.class).to(DruidProcessingConfig.class);
@@ -117,4 +121,23 @@ public Boolean isSegmentCacheConfigured(SegmentLoaderConfig segmentLoaderConfig)
   {
     return !segmentLoaderConfig.getLocations().isEmpty();
   }
+
+  /**
+   * provide a list of StorageLocation
+   * so that it can be injected into objects such as implementations of {@link StorageLocationSelectorStrategy}
+   */
+  @Provides
+  @LazySingleton
+  public List<StorageLocation> provideStorageLocation(SegmentLoaderConfig config)
+  {
+    return config.toStorageLocations();
+  }
+
+  /**
+   * a helper method for both storage module and independent unit test cases
+   */
+  public static void bindLocationSelectorStrategy(Binder binder)
+  {
+    JsonConfigProvider.bind(binder, "druid.segmentCache.locationSelector", StorageLocationSelectorStrategy.class);
+  }
 }

server/src/main/java/org/apache/druid/segment/loading/LeastBytesUsedStorageLocationSelectorStrategy.java

@@ -19,6 +19,8 @@
 
 package org.apache.druid.segment.loading;
 
+import com.fasterxml.jackson.annotation.JacksonInject;
+import com.fasterxml.jackson.annotation.JsonCreator;
 import com.google.common.collect.Ordering;
 
 import java.util.Comparator;
@@ -34,9 +36,10 @@ public class LeastBytesUsedStorageLocationSelectorStrategy implements StorageLoc
   private static final Ordering<StorageLocation> ORDERING = Ordering.from(Comparator
       .comparingLong(StorageLocation::currSizeBytes));
 
-  private List<StorageLocation> storageLocations;
+  private final List<StorageLocation> storageLocations;
 
-  public LeastBytesUsedStorageLocationSelectorStrategy(List<StorageLocation> storageLocations)
+  @JsonCreator
+  public LeastBytesUsedStorageLocationSelectorStrategy(@JacksonInject final List<StorageLocation> storageLocations)
   {
     this.storageLocations = storageLocations;
   }

server/src/main/java/org/apache/druid/segment/loading/MostAvailableSizeStorageLocationSelectorStrategy.java

@@ -19,6 +19,8 @@
 
 package org.apache.druid.segment.loading;
 
+import com.fasterxml.jackson.annotation.JacksonInject;
+import com.fasterxml.jackson.annotation.JsonCreator;
 import com.google.common.collect.Ordering;
 
 import java.util.Comparator;
@@ -35,9 +37,10 @@ public class MostAvailableSizeStorageLocationSelectorStrategy implements Storage
       .comparingLong(StorageLocation::availableSizeBytes)
       .reversed());
 
-  private List<StorageLocation> storageLocations;
+  private final List<StorageLocation> storageLocations;
 
-  public MostAvailableSizeStorageLocationSelectorStrategy(List<StorageLocation> storageLocations)
+  @JsonCreator
+  public MostAvailableSizeStorageLocationSelectorStrategy(@JacksonInject final List<StorageLocation> storageLocations)
   {
     this.storageLocations = storageLocations;
   }

server/src/main/java/org/apache/druid/segment/loading/RandomStorageLocationSelectorStrategy.java

@@ -19,6 +19,9 @@
 
 package org.apache.druid.segment.loading;
 
+import com.fasterxml.jackson.annotation.JacksonInject;
+import com.fasterxml.jackson.annotation.JsonCreator;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
@@ -33,7 +36,8 @@ public class RandomStorageLocationSelectorStrategy implements StorageLocationSel
 
   private final List<StorageLocation> storageLocations;
 
-  public RandomStorageLocationSelectorStrategy(List<StorageLocation> storageLocations)
+  @JsonCreator
+  public RandomStorageLocationSelectorStrategy(@JacksonInject final List<StorageLocation> storageLocations)
   {
     this.storageLocations = storageLocations;
   }
@@ -45,5 +49,4 @@ public Iterator<StorageLocation> getLocations()
     Collections.shuffle(copyLocation);
     return copyLocation.iterator();
   }
-
 }

server/src/main/java/org/apache/druid/segment/loading/RoundRobinStorageLocationSelectorStrategy.java

@@ -19,6 +19,9 @@
 
 package org.apache.druid.segment.loading;
 
+import com.fasterxml.jackson.annotation.JacksonInject;
+import com.fasterxml.jackson.annotation.JsonCreator;
+
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
@@ -32,19 +35,20 @@
  */
 public class RoundRobinStorageLocationSelectorStrategy implements StorageLocationSelectorStrategy
 {
-
   private final List<StorageLocation> storageLocations;
   private final AtomicInteger startIndex = new AtomicInteger(0);
 
-  public RoundRobinStorageLocationSelectorStrategy(List<StorageLocation> storageLocations)
+  @JsonCreator
+  public RoundRobinStorageLocationSelectorStrategy(@JacksonInject List<StorageLocation> storageLocations)
   {
     this.storageLocations = storageLocations;
   }
 
   @Override
   public Iterator<StorageLocation> getLocations()
   {
-    return new Iterator<StorageLocation>() {
+    return new Iterator<StorageLocation>()
+    {
 
       private final int numStorageLocations = storageLocations.size();
       private int remainingIterations = numStorageLocations;
@@ -73,5 +77,4 @@ public StorageLocation next()
       }
     };
   }
-
 }

server/src/main/java/org/apache/druid/segment/loading/SegmentLoaderConfig.java

@@ -20,14 +20,14 @@
 package org.apache.druid.segment.loading;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.Lists;
 import org.apache.druid.utils.JvmUtils;
 
 import java.io.File;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
 
 /**
  *
@@ -55,9 +55,6 @@ public class SegmentLoaderConfig
   @JsonProperty("numBootstrapThreads")
   private Integer numBootstrapThreads = null;
 
-  @JsonProperty("locationSelectorStrategy")
-  private StorageLocationSelectorStrategy locationSelectorStrategy;
-
   @JsonProperty
   private File infoDir = null;
 
@@ -101,15 +98,6 @@ public int getNumBootstrapThreads()
     return numBootstrapThreads == null ? numLoadingThreads : numBootstrapThreads;
   }
 
-  public StorageLocationSelectorStrategy getStorageLocationSelectorStrategy(List<StorageLocation> storageLocations)
-  {
-    if (locationSelectorStrategy == null) {
-      // default strategy if no strategy is specified in the config
-      locationSelectorStrategy = new LeastBytesUsedStorageLocationSelectorStrategy(storageLocations);
-    }
-    return locationSelectorStrategy;
-  }
-
   public File getInfoDir()
   {
     if (infoDir == null) {
@@ -140,11 +128,19 @@ public SegmentLoaderConfig withLocations(List<StorageLocationConfig> locations)
     return retVal;
   }
 
-  @VisibleForTesting
-  SegmentLoaderConfig withStorageLocationSelectorStrategy(StorageLocationSelectorStrategy strategy)
+  /**
+   * Convert StorageLocationConfig objects to StorageLocation objects
+   *
+   * Note: {@link #getLocations} is called instead of variable access because some testcases overrides this method
+   */
+  public List<StorageLocation> toStorageLocations()
   {
-    this.locationSelectorStrategy = strategy;
-    return this;
+    return this.getLocations()
+               .stream()
+               .map(locationConfig -> new StorageLocation(locationConfig.getPath(),
+                                                          locationConfig.getMaxSize(),
+                                                          locationConfig.getFreeSpacePercent()))
+               .collect(Collectors.toList());
   }
 
   @Override
@@ -154,7 +150,6 @@ public String toString()
            "locations=" + locations +
            ", deleteOnRemove=" + deleteOnRemove +
            ", dropSegmentDelayMillis=" + dropSegmentDelayMillis +
-           ", locationSelectorStrategy=" + locationSelectorStrategy +
            ", infoDir=" + infoDir +
            '}';
   }

server/src/main/java/org/apache/druid/segment/loading/SegmentLoaderLocalCacheManager.java

@@ -30,9 +30,9 @@
 import org.apache.druid.segment.Segment;
 import org.apache.druid.timeline.DataSegment;
 
+import javax.annotation.Nonnull;
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
@@ -82,24 +82,48 @@ public class SegmentLoaderLocalCacheManager implements SegmentLoader
   @Inject
   public SegmentLoaderLocalCacheManager(
       IndexIO indexIO,
+      List<StorageLocation> locations,
       SegmentLoaderConfig config,
+      @Nonnull StorageLocationSelectorStrategy strategy,
       @Json ObjectMapper mapper
   )
   {
     this.indexIO = indexIO;
     this.config = config;
     this.jsonMapper = mapper;
-    this.locations = new ArrayList<>();
-    for (StorageLocationConfig locationConfig : config.getLocations()) {
-      locations.add(
-          new StorageLocation(
-              locationConfig.getPath(),
-              locationConfig.getMaxSize(),
-              locationConfig.getFreeSpacePercent()
-          )
-      );
-    }
-    this.strategy = config.getStorageLocationSelectorStrategy(locations);
+    this.locations = locations;
+    this.strategy = strategy;
+    log.info("Using storage location strategy: [%s]", this.strategy.getClass().getSimpleName());
+  }
+
+  @VisibleForTesting
+  SegmentLoaderLocalCacheManager(
+      IndexIO indexIO,
+      SegmentLoaderConfig config,
+      @Nonnull StorageLocationSelectorStrategy strategy,
+      @Json ObjectMapper mapper
+  )
+  {
+    this(indexIO, config.toStorageLocations(), config, strategy, mapper);
+  }
+
+  /**
+   * creates instance with default storage location selector strategy
+   *
+   * This ctor is mainly for test cases, including test cases in other modules
+   */
+  public SegmentLoaderLocalCacheManager(
+      IndexIO indexIO,
+      SegmentLoaderConfig config,
+      @Json ObjectMapper mapper
+  )
+  {
+    this.indexIO = indexIO;
+    this.config = config;
+    this.jsonMapper = mapper;
+    this.locations = config.toStorageLocations();
+    this.strategy = new LeastBytesUsedStorageLocationSelectorStrategy(locations);
+    log.info("Using storage location strategy: [%s]", this.strategy.getClass().getSimpleName());
   }
 
   @Override

server/src/main/java/org/apache/druid/segment/loading/StorageLocationSelectorStrategy.java

@@ -34,7 +34,7 @@
  * https://github.com/apache/druid/pull/8038#discussion_r325520829 of PR https://github
  * .com/apache/druid/pull/8038 for more details.
  */
-@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl =
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "strategy", defaultImpl =
     LeastBytesUsedStorageLocationSelectorStrategy.class)
 @JsonSubTypes(value = {
     @JsonSubTypes.Type(name = "leastBytesUsed", value = LeastBytesUsedStorageLocationSelectorStrategy.class),