Github user marmbrus commented on a diff in the pull request:
https://github.com/apache/spark/pull/17219#discussion_r105061689
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/OffsetCommitLog.scala
---
@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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.apache.spark.sql.execution.streaming
+
+import java.io.{InputStream, OutputStream}
+import java.nio.charset.StandardCharsets._
+
+import scala.io.{Source => IOSource}
+
+import org.apache.spark.sql.SparkSession
+
+class OffsetCommitLog(sparkSession: SparkSession, path: String)
+ extends HDFSMetadataLog[Option[String]](sparkSession, path) {
+
+ override protected def deserialize(in: InputStream): Option[String] = {
+ // called inside a try-finally where the underlying stream is closed
in the caller
+ val lines = IOSource.fromInputStream(in, UTF_8.name()).getLines()
+ if (!lines.hasNext) {
+ throw new IllegalStateException("Incomplete log file")
+ }
+ val version = lines.next()
+ if (version != OffsetCommitLog.VERSION) {
+ throw new IllegalStateException(s"Unknown log version: ${version}")
+ }
+ // read metadata
+ lines.next().trim match {
+ case OffsetCommitLog.SERIALIZED_VOID => None
+ case metadata => Some(metadata)
+ }
+ }
+
+ override protected def serialize(metadata: Option[String], out:
OutputStream): Unit = {
+ // called inside a try-finally where the underlying stream is closed
in the caller
+ out.write(OffsetCommitLog.VERSION.getBytes(UTF_8))
+ out.write('\n')
+
+ // write metadata or void
+
out.write(metadata.getOrElse(OffsetCommitLog.SERIALIZED_VOID).getBytes(UTF_8))
+ }
+}
+
+object OffsetCommitLog {
+ private val VERSION = "v1"
+ private val SERIALIZED_VOID = "-"
--- End diff --
Why not make this an empty json object? `{}`
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
