xuanyuanking commented on a change in pull request #32582:
URL: https://github.com/apache/spark/pull/32582#discussion_r643852461



##########
File path: 
sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/state/RocksDBFileManager.scala
##########
@@ -17,18 +17,270 @@
 
 package org.apache.spark.sql.execution.streaming.state
 
-import java.io.File
+import java.io.{File, FileInputStream, InputStream}
 import java.nio.charset.StandardCharsets.UTF_8
 import java.nio.file.Files
+import java.util.UUID
+import java.util.concurrent.ConcurrentHashMap
+import java.util.zip.{ZipEntry, ZipOutputStream}
 
+import scala.collection.JavaConverters._
 import scala.collection.Seq
 
 import com.fasterxml.jackson.annotation.JsonInclude.Include
 import com.fasterxml.jackson.databind.{DeserializationFeature, ObjectMapper}
 import com.fasterxml.jackson.module.scala.{DefaultScalaModule, 
ScalaObjectMapper}
+import org.apache.commons.io.{FilenameUtils, IOUtils}
+import org.apache.hadoop.conf.Configuration
+import org.apache.hadoop.fs.Path
 import org.json4s.NoTypeHints
 import org.json4s.jackson.Serialization
 
+import org.apache.spark.internal.Logging
+import org.apache.spark.sql.execution.streaming.CheckpointFileManager
+import org.apache.spark.util.Utils
+
+/**
+ * Class responsible for syncing RocksDB checkpoint files from local disk to 
DFS.
+ * Every version checkpoint is saved in specific directory structure that 
allows successive
+ * versions to reuse to SST data files and archived log files. This allows 
each commit to be
+ * incremental, only new SST files and archived log files generated by RocksDB 
will be uploaded.
+ * The directory structures on local disk and in DFS are as follows.
+ *
+ * Local checkpoint dir structure
+ * ------------------------------
+ * RocksDB generates a bunch of files in the local checkpoint directory. The 
most important among
+ * them are the SST files; they are the actual log structured data files. Rest 
of the files contain
+ * the metadata necessary for RocksDB to read the SST files and start from the 
checkpoint.
+ * Note that the SST files are hard links to files in the RocksDB's working 
directory, and therefore
+ * successive checkpoints can share some of the SST files. So these SST files 
have to be copied to
+ * DFS in shared directory such that different committed versions can save 
them.
+ *
+ * We consider both SST files and archived log files as immutable files which 
can be shared between
+ * different checkpoints.
+ *
+ *    localCheckpointDir
+ *                  |
+ *                  +-- OPTIONS-000005
+ *                  +-- MANIFEST-000008
+ *                  +-- CURRENT
+ *                  +-- 00007.sst
+ *                  +-- 00011.sst
+ *                  +-- archive
+ *                  |     +-- 00008.log
+ *                  |     +-- 00013.log
+ *                  ...
+ *
+ *
+ * DFS directory structure after saving to DFS as version 10
+ * -----------------------------------------------------------
+ * The SST and archived log files are given unique file names and copied to 
the shared subdirectory.
+ * Every version maintains a mapping of local immutable file name to the 
unique file name in DFS.
+ * This mapping is saved in a JSON file (named `metadata`), which is zipped 
along with other
+ * checkpoint files into a single file `[version].zip`.
+ *
+ *    dfsRootDir
+ *           |
+ *           +-- SSTs
+ *           |      +-- 00007-[uuid1].sst
+ *           |      +-- 00011-[uuid2].sst
+ *           +-- logs
+ *           |      +-- 00008-[uuid3].log
+ *           |      +-- 00013-[uuid4].log
+ *           +-- 10.zip
+ *           |      +-- metadata         <--- contains mapping between 
00007.sst and [uuid1].sst,
+ *                                            and the mapping between 
00008.log and [uuid3].log
+ *           |      +-- OPTIONS-000005
+ *           |      +-- MANIFEST-000008
+ *           |      +-- CURRENT
+ *           |      ...
+ *           |
+ *           +-- 9.zip
+ *           +-- 8.zip
+ *           ...
+ *
+ * Note the following.
+ * - Each [version].zip is a complete description of all the data and metadata 
needed to recover
+ *   a RocksDB instance at the corresponding version. This is unlike the 
[version].delta files of
+ *   HDFSBackedStateStore where previous delta files needs to be read to be 
recovered.
+ * - This is safe wrt speculatively executed tasks running concurrently in 
different executors
+ *   as each task would upload a different copy of the generated immutable 
files and
+ *   atomically update the [version].zip.
+ * - Immutable files are identified uniquely based on their file name and file 
size.
+ * - Immutable files can be reused only across adjacent checkpoints/versions.
+ * - This class is thread-safe. Specifically, it is safe to concurrently 
delete old files from a
+ *   different thread than the task thread saving files.
+ *
+ * @param dfsRootDir  Directory where the [version].zip files will be stored
+ * @param localTempDir Local directory for temporary work
+ * @param hadoopConf   Hadoop configuration for talking to DFS
+ * @param loggingId    Id that will be prepended in logs for isolating 
concurrent RocksDBs
+ */
+class RocksDBFileManager(
+  dfsRootDir: String,
+  localTempDir: File,
+  hadoopConf: Configuration,
+  loggingId: String = "")
+  extends Logging {
+
+  import RocksDBImmutableFile._
+
+  private val versionToRocksDBFiles = new ConcurrentHashMap[Long, 
Seq[RocksDBImmutableFile]]
+  private lazy val fm = CheckpointFileManager.create(new Path(dfsRootDir), 
hadoopConf)
+  private val fs = new Path(dfsRootDir).getFileSystem(hadoopConf)
+
+  /** Save all the files in given local checkpoint directory as a committed 
version in DFS */
+  def saveCheckpointToDfs(checkpointDir: File, version: Long, numKeys: Long): 
Unit = {
+    logFilesInDir(checkpointDir, s"Saving checkpoint files for version 
$version")
+    val allCheckpointFiles = listRocksDBFiles(checkpointDir)
+    val (localImmutableFiles, localOtherFiles) = 
allCheckpointFiles.partition(isImmutableFile)
+    val rocksDBFiles = saveImmutableFilesToDfs(version, checkpointDir, 
localImmutableFiles)
+    val metadata = RocksDBCheckpointMetadata(rocksDBFiles, numKeys)
+    rememberImmutableFiles(version, rocksDBFiles)
+    val metadataFile = localMetadataFile(checkpointDir)
+    metadata.writeToFile(metadataFile)
+    logInfo(s"Written metadata for version $version:\n${metadata.prettyJson}")
+
+    if (version <= 0 && numKeys == 0) {
+      // If we're writing the initial version and there's no data, we have to 
explicitly initialize
+      // the root directory. Normally saveImmutableFilesToDfs will do this 
initialization, but
+      // when there's no data that method won't write any files, and 
zipToDfsFile uses the
+      // CheckpointFileManager.createAtomic API which doesn't auto-initialize 
parent directories.
+      fm.mkdirs(new Path(dfsRootDir))
+    }
+    zipToDfsFile(localOtherFiles :+ metadataFile, dfsBatchZipFile(version))
+    logInfo(s"Saved checkpoint file for version $version")
+  }
+
+  /** Save immutable files to DFS directory */
+  private def saveImmutableFilesToDfs(
+    version: Long,
+    localDir: File,
+    localFiles: Seq[File]): Seq[RocksDBImmutableFile] = {
+    // Get the immutable files used in previous versions, as some of those 
uploaded files can be
+    // reused for this version
+    logInfo(s"Saving RocksDB files to DFS for $version")
+    val prevFilesToSizes = versionToRocksDBFiles.values.asScala.flatten.map { 
f =>
+      f.localFileName -> f
+    }.toMap
+
+    var bytesCopied = 0L
+    var filesCopied = 0L
+    var filesReused = 0L
+
+    val immutableFiles = localFiles.map { localFile =>
+      prevFilesToSizes
+        .get(localFile.getName)
+        .filter(_.isSameFile(localFile))
+        .map { reusable =>
+          filesReused += 1
+          reusable
+        }.getOrElse {
+        val localFileName = localFile.getName
+        val dfsFileName = newDFSFileName(localFileName)
+        val dfsFile = dfsFilePath(dfsFileName)
+        // Note: The implementation of copyFromLocalFile() closes the output 
stream when there is
+        // any exception while copying. So this may generate partial files on 
DFS. But that is
+        // okay because until the main [version].zip file is written, those 
partial files are
+        // not going to be used at all. Eventually these files should get 
cleared.
+        fs.copyFromLocalFile(
+          new Path(localFile.getAbsoluteFile.toURI), dfsFile)
+        val localFileSize = localFile.length()
+        logInfo(s"Copied $localFile to $dfsFile - $localFileSize bytes")
+        filesCopied += 1
+        bytesCopied += localFileSize
+
+        RocksDBImmutableFile(localFile.getName, dfsFileName, localFileSize)
+      }
+    }
+    logInfo(s"Copied $filesCopied files ($bytesCopied bytes) from local to" +

Review comment:
       Sure, done in 3800c51




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