support atomic writes for local deep storage (#3521)

* Use atomic writes for local deep storage

* fix pr issues

* use defaultObjMapper for test

* move tmp pushes to a intermediate dir

* minor refactor

api/src/main/java/io/druid/timeline/partition/NoneShardSpec.java

@@ -20,6 +20,7 @@
 package io.druid.timeline.partition;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Range;
 import io.druid.data.input.InputRow;
@@ -55,6 +56,7 @@ public class NoneShardSpec implements ShardSpec
   }
 
   @Override
+  @JsonIgnore
   public int getPartitionNum()
   {
     return 0;

api/src/test/java/io/druid/timeline/partition/NoneShardSpecTest.java

@@ -5,6 +5,8 @@ import io.druid.TestObjectMapper;
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.io.IOException;
+
 public class NoneShardSpecTest
 {
   @Test
@@ -28,4 +30,13 @@ public class NoneShardSpecTest
     Assert.assertTrue(serde1 == serde2);
     Assert.assertTrue(one == serde1);
   }
+
+  @Test
+  public void testPartitionFieldIgnored() throws IOException
+  {
+    final String jsonStr = "{\"type\": \"none\",\"partitionNum\": 2}";
+    ObjectMapper mapper = new TestObjectMapper();
+    final ShardSpec noneShardSpec = mapper.readValue(jsonStr, ShardSpec.class);
+    noneShardSpec.equals(NoneShardSpec.instance());
+  }
 }

server/src/main/java/io/druid/segment/loading/LocalDataSegmentPusher.java

@@ -29,9 +29,12 @@ import io.druid.java.util.common.CompressionUtils;
 import io.druid.java.util.common.logger.Logger;
 import io.druid.segment.SegmentUtils;
 import io.druid.timeline.DataSegment;
+import org.apache.commons.io.FileUtils;
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.FileAlreadyExistsException;
+import java.util.UUID;
 
 /**
  */
@@ -70,7 +73,9 @@ public class LocalDataSegmentPusher implements DataSegmentPusher
   @Override
   public DataSegment push(File dataSegmentFile, DataSegment segment) throws IOException
   {
-    File outDir = new File(config.getStorageDirectory(), DataSegmentPusherUtil.getStorageDir(segment));
+    final String storageDir = DataSegmentPusherUtil.getStorageDir(segment);
+    final File baseStorageDir = config.getStorageDirectory();
+    final File outDir = new File(baseStorageDir, storageDir);
 
     log.info("Copying segment[%s] to local filesystem at location[%s]", segment.getIdentifier(), outDir.toString());
 
@@ -88,19 +93,49 @@ public class LocalDataSegmentPusher implements DataSegmentPusher
       );
     }
 
-    if (!outDir.mkdirs() && !outDir.isDirectory()) {
-      throw new IOException(String.format("Cannot create directory[%s]", outDir));
+    final File tmpOutDir = new File(baseStorageDir, intermediateDirFor(storageDir));
+    log.info("Creating intermediate directory[%s] for segment[%s]", tmpOutDir.toString(), segment.getIdentifier());
+    final long size = compressSegment(dataSegmentFile, tmpOutDir);
+
+    final DataSegment dataSegment = createDescriptorFile(
+      segment.withLoadSpec(makeLoadSpec(new File(outDir, "index.zip")))
+             .withSize(size)
+             .withBinaryVersion(SegmentUtils.getVersionFromDir(dataSegmentFile)),
+      tmpOutDir
+    );
+
+    // moving the temporary directory to the final destination, once success the potentially concurrent push operations
+    // will be failed and will read the descriptor.json created by current push operation directly
+    createDirectoryIfNotExists(outDir.getParentFile());
+    try {
+      java.nio.file.Files.move(tmpOutDir.toPath(), outDir.toPath());
     }
+    catch (FileAlreadyExistsException e) {
+      log.warn("Push destination directory[%s] exists, ignore this message if replication is configured.", outDir);
+      FileUtils.deleteDirectory(tmpOutDir);
+      return jsonMapper.readValue(new File(outDir, "descriptor.json"), DataSegment.class);
+    }
+    return dataSegment;
+  }
+
+  private void createDirectoryIfNotExists(File directory) throws IOException
+  {
+    if (!directory.mkdirs() && !directory.isDirectory()) {
+      throw new IOException(String.format("Cannot create directory[%s]", directory.toString()));
+    }
+  }
+
+  private String intermediateDirFor(String storageDir)
+  {
+    return "intermediate_pushes/" + storageDir + "." + UUID.randomUUID().toString();
+  }
+
+  private long compressSegment(File dataSegmentFile, File outDir) throws IOException
+  {
+    createDirectoryIfNotExists(outDir);
     File outFile = new File(outDir, "index.zip");
     log.info("Compressing files from[%s] to [%s]", dataSegmentFile, outFile);
-    long size = CompressionUtils.zip(dataSegmentFile, outFile);
-
-    return createDescriptorFile(
-        segment.withLoadSpec(makeLoadSpec(outFile))
-               .withSize(size)
-               .withBinaryVersion(SegmentUtils.getVersionFromDir(dataSegmentFile)),
-        outDir
-    );
+    return CompressionUtils.zip(dataSegmentFile, outFile);
   }
 
   private DataSegment createDescriptorFile(DataSegment segment, File outDir) throws IOException

server/src/test/java/io/druid/segment/loading/LocalDataSegmentPusherTest.java

@@ -23,6 +23,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.collect.ImmutableList;
 import com.google.common.io.Files;
 import com.google.common.primitives.Ints;
+import io.druid.jackson.DefaultObjectMapper;
 import io.druid.timeline.DataSegment;
 import io.druid.timeline.partition.NoneShardSpec;
 import org.joda.time.Interval;
@@ -48,15 +49,15 @@ public class LocalDataSegmentPusherTest
   LocalDataSegmentPusherConfig config;
   File dataSegmentFiles;
   DataSegment dataSegment = new DataSegment(
-      "ds",
-      new Interval(0, 1),
-      "v1",
-      null,
-      null,
-      null,
-      NoneShardSpec.instance(),
-      null,
-      -1
+    "ds",
+    new Interval(0, 1),
+    "v1",
+    null,
+    null,
+    null,
+    NoneShardSpec.instance(),
+    null,
+    -1
   );
 
   @Before
@@ -64,7 +65,7 @@ public class LocalDataSegmentPusherTest
   {
     config = new LocalDataSegmentPusherConfig();
     config.storageDirectory = temporaryFolder.newFolder();
-    localDataSegmentPusher = new LocalDataSegmentPusher(config, new ObjectMapper());
+    localDataSegmentPusher = new LocalDataSegmentPusher(config, new DefaultObjectMapper());
     dataSegmentFiles = temporaryFolder.newFolder();
     Files.asByteSink(new File(dataSegmentFiles, "version.bin")).write(Ints.toByteArray(0x9));
   }
@@ -103,6 +104,17 @@ public class LocalDataSegmentPusherTest
     }
   }
 
+  @Test
+  public void testFirstPushWinsForConcurrentPushes() throws IOException
+  {
+    File replicatedDataSegmentFiles = temporaryFolder.newFolder();
+    Files.asByteSink(new File(replicatedDataSegmentFiles, "version.bin")).write(Ints.toByteArray(0x8));
+    DataSegment returnSegment1 = localDataSegmentPusher.push(dataSegmentFiles, dataSegment);
+    DataSegment returnSegment2 = localDataSegmentPusher.push(replicatedDataSegmentFiles, dataSegment);
+
+    Assert.assertEquals(returnSegment1, returnSegment2);
+  }
+
   @Test
   public void testPushCannotCreateDirectory() throws IOException
   {