Dont commit on consumer seek

docs/Consuming.md

@@ -329,6 +329,17 @@ consumer.seek({ topic: 'example', partition: 0, offset: 12384 })
 
 Upon seeking to an offset, any messages in active batches are marked as stale and discarded, making sure the next message read for the partition is from the offset sought to. Make sure to check `isStale()` before processing a message using [the `eachBatch` interface](#each-batch) of `consumer.run`.
 
+By default, the consumer will commit the offset seeked. To disable this, set the [`autoCommit`](#auto-commit) option to `false` on the consumer.
+
+```javascript
+consumer.run({
+    autoCommit: false,
+    eachMessage: async ({ topic, message }) => true
+})
+// This will now only resolve the previous offset, not commit it
+consumer.seek({ topic: 'example', partition: 0, offset: 12384 })
+```
+
 ## <a name="custom-partition-assigner"></a> Custom partition assigner
 
 It's possible to configure the strategy the consumer will use to distribute partitions amongst the consumer group. KafkaJS has a round robin assigner configured by default.

src/consumer/__tests__/seek.spec.js

@@ -1,3 +1,4 @@
+const createAdmin = require('../../admin')
 const createProducer = require('../../producer')
 const createConsumer = require('../index')
 const { KafkaJSNonRetriableError } = require('../../errors')
@@ -163,5 +164,51 @@ describe('Consumer', () => {
         },
       ])
     })
+
+    describe('When "autoCommit" is false', () => {
+      let admin
+
+      beforeEach(() => {
+        admin = createAdmin({ logger: newLogger(), cluster })
+      })
+
+      afterEach(async () => {
+        admin && (await admin.disconnect())
+      })
+
+      it('should not commit the offset', async () => {
+        await Promise.all([consumer, producer, admin].map(client => client.connect()))
+
+        await producer.send({
+          acks: 1,
+          topic: topicName,
+          messages: [1, 2, 3].map(n => ({ key: `key-${n}`, value: `value-${n}` })),
+        })
+        await consumer.subscribe({ topic: topicName, fromBeginning: true })
+
+        const messagesConsumed = []
+        consumer.run({
+          autoCommit: false,
+          eachMessage: async event => messagesConsumed.push(event),
+        })
+        consumer.seek({ topic: topicName, partition: 0, offset: 2 })
+
+        await waitForConsumerToJoinGroup(consumer)
+        await expect(waitForMessages(messagesConsumed, { number: 1 })).resolves.toEqual([
+          {
+            topic: topicName,
+            partition: 0,
+            message: expect.objectContaining({ offset: '2' }),
+          },
+        ])
+
+        await expect(admin.fetchOffsets({ groupId, topic: topicName })).resolves.toEqual([
+          expect.objectContaining({
+            partition: 0,
+            offset: '-1',
+          }),
+        ])
+      })
+    })
   })
 })

src/consumer/consumerGroup.js

@@ -55,6 +55,7 @@ module.exports = class ConsumerGroup {
     minBytes,
     maxBytes,
     maxWaitTimeInMs,
+    autoCommit,
     autoCommitInterval,
     autoCommitThreshold,
     isolationLevel,
@@ -77,6 +78,7 @@ module.exports = class ConsumerGroup {
     this.minBytes = minBytes
     this.maxBytes = maxBytes
     this.maxWaitTime = maxWaitTimeInMs
+    this.autoCommit = autoCommit
     this.autoCommitInterval = autoCommitInterval
     this.autoCommitThreshold = autoCommitThreshold
     this.isolationLevel = isolationLevel
@@ -274,6 +276,7 @@ module.exports = class ConsumerGroup {
         }),
         {}
       ),
+      autoCommit: this.autoCommit,
       autoCommitInterval: this.autoCommitInterval,
       autoCommitThreshold: this.autoCommitThreshold,
       coordinator,

src/consumer/index.js

@@ -82,7 +82,7 @@ module.exports = ({
     )
   }
 
-  const createConsumerGroup = ({ autoCommitInterval, autoCommitThreshold }) => {
+  const createConsumerGroup = ({ autoCommit, autoCommitInterval, autoCommitThreshold }) => {
     return new ConsumerGroup({
       logger: rootLogger,
       topics: keys(topics),
@@ -98,6 +98,7 @@ module.exports = ({
       maxBytes,
       maxWaitTimeInMs,
       instrumentationEmitter,
+      autoCommit,
       autoCommitInterval,
       autoCommitThreshold,
       isolationLevel,
@@ -218,6 +219,7 @@ module.exports = ({
     }
 
     consumerGroup = createConsumerGroup({
+      autoCommit,
       autoCommitInterval,
       autoCommitThreshold,
     })

src/consumer/offsetManager/index.js

@@ -18,6 +18,7 @@ module.exports = class OffsetManager {
    * @param {import("../../../types").Cluster} options.cluster
    * @param {import("../../../types").Broker} options.coordinator
    * @param {import("../../../types").IMemberAssignment} options.memberAssignment
+   * @param {boolean} options.autoCommit
    * @param {number | null} options.autoCommitInterval
    * @param {number | null} options.autoCommitThreshold
    * @param {{[topic: string]: { fromBeginning: boolean }}} options.topicConfigurations
@@ -30,6 +31,7 @@ module.exports = class OffsetManager {
     cluster,
     coordinator,
     memberAssignment,
+    autoCommit,
     autoCommitInterval,
     autoCommitThreshold,
     topicConfigurations,
@@ -54,6 +56,7 @@ module.exports = class OffsetManager {
     this.generationId = generationId
     this.memberId = memberId
 
+    this.autoCommit = autoCommit
     this.autoCommitInterval = autoCommitInterval
     this.autoCommitThreshold = autoCommitThreshold
     this.lastCommit = Date.now()
@@ -166,6 +169,17 @@ module.exports = class OffsetManager {
       return
     }
 
+    if (!this.autoCommit) {
+      this.resolveOffset({
+        topic,
+        partition,
+        offset: Long.fromValue(offset)
+          .subtract(1)
+          .toString(),
+      })
+      return
+    }
+
     const { groupId, generationId, memberId } = this
     const coordinator = await this.getCoordinator()
 

src/consumer/runner.js

@@ -167,7 +167,7 @@ module.exports = class Runner extends EventEmitter {
 
       this.consumerGroup.resolveOffset({ topic, partition, offset: message.offset })
       await this.consumerGroup.heartbeat({ interval: this.heartbeatInterval })
-      await this.consumerGroup.commitOffsetsIfNecessary()
+      await this.autoCommitOffsetsIfNecessary()
     }
   }