KIP-320 implementation, WIP

CHANGELOG.md

@@ -1,3 +1,24 @@
+# librdkafka v2.1.0
+
+librdkafka v2.1.0 is a feature release:
+
+* [KIP-320](https://cwiki.apache.org/confluence/display/KAFKA/KIP-320%3A+Allow+fetchers+to+detect+and+handle+log+truncation)
+  Allow fetchers to detect and handle log truncation (#4122).
+
+## Enhancements
+
+ * Added `rd_kafka_topic_partition_get_leader_epoch()` (and `set..()`).
+ * Added partition leader epoch APIs:
+   - `rd_kafka_topic_partition_get_leader_epoch()` (and `set..()`)
+   - `rd_kafka_message_leader_epoch()`
+   - `rd_kafka_*assign()` and `rd_kafka_seek_partitions()` now supports
+     partitions with a leader epoch set.
+   - `rd_kafka_offsets_for_times()` will return per-partition leader-epochs.
+   - `leader_epoch`, `stored_leader_epoch`, and `committed_leader_epoch`
+     added to per-partition statistics.
+
+
+
 # librdkafka v2.0.2
 
 librdkafka v2.0.2 is a bugfix release:

INTRODUCTION.md

@@ -1887,7 +1887,7 @@ The [Apache Kafka Implementation Proposals (KIPs)](https://cwiki.apache.org/conf
 | KIP-289 - Consumer group.id default to NULL                              | 2.2.0                       | Supported                                                                                     |
 | KIP-294 - SSL endpoint verification                                      | 2.0.0                       | Supported                                                                                     |
 | KIP-302 - Use all addresses for resolved broker hostname                 | 2.1.0                       | Supported                                                                                     |
-| KIP-320 - Consumer: handle log truncation                                | 2.1.0, 2.2.0                | Not supported                                                                                 |
+| KIP-320 - Consumer: handle log truncation                                | 2.1.0, 2.2.0                | Supported                                                                                     |
 | KIP-322 - DeleteTopics disabled error code                               | 2.1.0                       | Supported                                                                                     |
 | KIP-339 - AdminAPI: incrementalAlterConfigs                              | 2.3.0                       | Not supported                                                                                 |
 | KIP-341 - Update Sticky partition assignment data                        | 2.3.0                       | Not supported (superceeded by KIP-429)                                                        |
@@ -1953,7 +1953,7 @@ release of librdkafka.
 | 0       | Produce             | 9           | 7                       |
 | 1       | Fetch               | 13          | 11                      |
 | 2       | ListOffsets         | 7           | 2                       |
-| 3       | Metadata            | 12          | 4                       |
+| 3       | Metadata            | 12          | 9                       |
 | 8       | OffsetCommit        | 8           | 7                       |
 | 9       | OffsetFetch         | 8           | 7                       |
 | 10      | FindCoordinator     | 4           | 2                       |

STATISTICS.md

@@ -179,13 +179,16 @@ query_offset | int gauge | | Current/Last logical offset query
 next_offset | int gauge | | Next offset to fetch
 app_offset | int gauge | | Offset of last message passed to application + 1
 stored_offset | int gauge | | Offset to be committed
+stored_leader_epoch | int | | Partition leader epoch of stored offset
 committed_offset | int gauge | | Last committed offset
+committed_leader_epoch | int | | Partition leader epoch of committed offset
 eof_offset | int gauge | | Last PARTITION_EOF signaled offset
 lo_offset | int gauge | | Partition's low watermark offset on broker
 hi_offset | int gauge | | Partition's high watermark offset on broker
 ls_offset | int gauge | | Partition's last stable offset on broker, or same as hi_offset is broker version is less than 0.11.0.0.
 consumer_lag | int gauge | | Difference between (hi_offset or ls_offset) and committed_offset). hi_offset is used when isolation.level=read_uncommitted, otherwise ls_offset.
 consumer_lag_stored | int gauge | | Difference between (hi_offset or ls_offset) and stored_offset. See consumer_lag and stored_offset.
+leader_epoch | int | | Last known partition leader epoch, or -1 if unknown.
 txmsgs | int | | Total number of messages transmitted (produced)
 txbytes | int | | Total number of bytes transmitted for txmsgs
 rxmsgs | int | | Total number of messages consumed, not including ignored messages (due to offset, etc).

src-cpp/HandleImpl.cpp

@@ -391,6 +391,8 @@ rd_kafka_topic_partition_list_t *partitions_to_c_parts(
     rd_kafka_topic_partition_t *rktpar = rd_kafka_topic_partition_list_add(
         c_parts, tpi->topic_.c_str(), tpi->partition_);
     rktpar->offset = tpi->offset_;
+    if (tpi->leader_epoch_ != -1)
+      rd_kafka_topic_partition_set_leader_epoch(rktpar, tpi->leader_epoch_);
   }
 
   return c_parts;
@@ -412,8 +414,9 @@ void update_partitions_from_c_parts(
           dynamic_cast<RdKafka::TopicPartitionImpl *>(partitions[j]);
       if (!strcmp(p->topic, pp->topic_.c_str()) &&
           p->partition == pp->partition_) {
-        pp->offset_ = p->offset;
-        pp->err_    = static_cast<RdKafka::ErrorCode>(p->err);
+        pp->offset_       = p->offset;
+        pp->err_          = static_cast<RdKafka::ErrorCode>(p->err);
+        pp->leader_epoch_ = rd_kafka_topic_partition_get_leader_epoch(p);
       }
     }
   }

src-cpp/rdkafkacpp.h

@@ -324,6 +324,8 @@ enum ErrorCode {
   ERR__NOOP = -141,
   /** No offset to automatically reset to */
   ERR__AUTO_OFFSET_RESET = -140,
+  /** Partition log truncation detected */
+  ERR__LOG_TRUNCATION = -139,
 
   /** End internal error codes */
   ERR__END = -100,
@@ -1978,6 +1980,12 @@ class RD_EXPORT TopicPartition {
 
   /** @returns error code (if applicable) */
   virtual ErrorCode err() const = 0;
+
+  /** @brief Get partition leader epoch, or -1 if not known or relevant. */
+  virtual int32_t get_leader_epoch() = 0;
+
+  /** @brief Set partition leader epoch. */
+  virtual void set_leader_epoch(int32_t leader_epoch) = 0;
 };
 
 
@@ -2035,6 +2043,11 @@ class RD_EXPORT Topic {
    * The offset will be committed (written) to the broker (or file) according
    * to \p auto.commit.interval.ms or next manual offset-less commit call.
    *
+   * @deprecated This API lacks support for partition leader epochs, which makes
+   *             it at risk for unclean leader election log truncation issues.
+   *             Use KafkaConsumer::offsets_store() or
+   *             Message::offset_store() instead.
+   *
    * @remark \c enable.auto.offset.store must be set to \c false when using
    *         this API.
    *
@@ -2465,6 +2478,31 @@ class RD_EXPORT Message {
   /** @returns the broker id of the broker the message was produced to or
    *           fetched from, or -1 if not known/applicable. */
   virtual int32_t broker_id() const = 0;
+
+  /** @returns the message's partition leader epoch at the time the message was
+   *           fetched and if known, else -1. */
+  virtual int32_t leader_epoch() const = 0;
+
+  /**
+   * @brief Store offset +1 for the consumed message.
+   *
+   * The message offset + 1 will be committed to broker according
+   * to \c `auto.commit.interval.ms` or manual offset-less commit()
+   *
+   * @warning This method may only be called for partitions that are currently
+   *          assigned.
+   *          Non-assigned partitions will fail with ERR__STATE.
+   *
+   * @warning Avoid storing offsets after calling seek() (et.al) as
+   *          this may later interfere with resuming a paused partition, instead
+   *          store offsets prior to calling seek.
+   *
+   * @remark \c `enable.auto.offset.store` must be set to "false" when using
+   *         this API.
+   *
+   * @returns NULL on success or an error object on failure.
+   */
+  virtual Error *offset_store() = 0;
 };
 
 /**@}*/
@@ -2865,6 +2903,9 @@ class RD_EXPORT KafkaConsumer : public virtual Handle {
    * @remark \c enable.auto.offset.store must be set to \c false when using
    *         this API.
    *
+   * @remark The leader epoch, if set, will be used to fence outdated partition
+   *         leaders. See TopicPartition::set_leader_epoch().
+   *
    * @returns RdKafka::ERR_NO_ERROR on success, or
    *          RdKafka::ERR___UNKNOWN_PARTITION if none of the offsets could
    *          be stored, or

src-cpp/rdkafkacpp_int.h

@@ -540,6 +540,21 @@ class MessageImpl : public Message {
     return rd_kafka_message_broker_id(rkmessage_);
   }
 
+  int32_t leader_epoch() const {
+    return rd_kafka_message_leader_epoch(rkmessage_);
+  }
+
+
+  Error *offset_store() {
+    rd_kafka_error_t *c_error;
+
+    c_error = rd_kafka_offset_store_message(rkmessage_);
+
+    if (c_error)
+      return new ErrorImpl(c_error);
+    else
+      return NULL;
+  }
 
   RdKafka::Topic *topic_;
   rd_kafka_message_t *rkmessage_;
@@ -1227,21 +1242,24 @@ class TopicPartitionImpl : public TopicPartition {
       topic_(topic),
       partition_(partition),
       offset_(RdKafka::Topic::OFFSET_INVALID),
-      err_(ERR_NO_ERROR) {
+      err_(ERR_NO_ERROR),
+      leader_epoch_(-1) {
   }
 
   TopicPartitionImpl(const std::string &topic, int partition, int64_t offset) :
       topic_(topic),
       partition_(partition),
       offset_(offset),
-      err_(ERR_NO_ERROR) {
+      err_(ERR_NO_ERROR),
+      leader_epoch_(-1) {
   }
 
   TopicPartitionImpl(const rd_kafka_topic_partition_t *c_part) {
-    topic_     = std::string(c_part->topic);
-    partition_ = c_part->partition;
-    offset_    = c_part->offset;
-    err_       = static_cast<ErrorCode>(c_part->err);
+    topic_        = std::string(c_part->topic);
+    partition_    = c_part->partition;
+    offset_       = c_part->offset;
+    err_          = static_cast<ErrorCode>(c_part->err);
+    leader_epoch_ = rd_kafka_topic_partition_get_leader_epoch(c_part);
     // FIXME: metadata
   }
 
@@ -1266,6 +1284,14 @@ class TopicPartitionImpl : public TopicPartition {
     offset_ = offset;
   }
 
+  int32_t get_leader_epoch() {
+    return leader_epoch_;
+  }
+
+  void set_leader_epoch(int32_t leader_epoch) {
+    leader_epoch_ = leader_epoch_;
+  }
+
   std::ostream &operator<<(std::ostream &ostrm) const {
     return ostrm << topic_ << " [" << partition_ << "]";
   }
@@ -1274,6 +1300,7 @@ class TopicPartitionImpl : public TopicPartition {
   int partition_;
   int64_t offset_;
   ErrorCode err_;
+  int32_t leader_epoch_;
 };