Delete unneeded file

internal/consumers.go

@@ -1,139 +0,0 @@
-// Copyright 2017 Vector Creations Ltd
-//
-// Licensed 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 internal
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/Shopify/sarama"
-	"github.com/matrix-org/dendrite/internal/sqlutil"
-	"github.com/matrix-org/dendrite/setup/process"
-	"github.com/sirupsen/logrus"
-)
-
-// A PartitionStorer has the storage APIs needed by the consumer.
-type PartitionStorer interface {
-	// PartitionOffsets returns the offsets the consumer has reached for each partition.
-	PartitionOffsets(ctx context.Context, topic string) ([]sqlutil.PartitionOffset, error)
-	// SetPartitionOffset records where the consumer has reached for a partition.
-	SetPartitionOffset(ctx context.Context, topic string, partition int32, offset int64) error
-}
-
-// A ContinualConsumer continually consumes logs even across restarts. It requires a PartitionStorer to
-// remember the offset it reached.
-type ContinualConsumer struct {
-	// The parent context for the listener, stop consuming when this context is done
-	Process *process.ProcessContext
-	// The component name
-	ComponentName string
-	// The kafkaesque topic to consume events from.
-	// This is the name used in kafka to identify the stream to consume events from.
-	Topic string
-	// A kafkaesque stream consumer providing the APIs for talking to the event source.
-	// The interface is taken from a client library for Apache Kafka.
-	// But any equivalent event streaming protocol could be made to implement the same interface.
-	Consumer sarama.Consumer
-	// A thing which can load and save partition offsets for a topic.
-	PartitionStore PartitionStorer
-	// ProcessMessage is a function which will be called for each message in the log. Return an error to
-	// stop processing messages. See ErrShutdown for specific control signals.
-	ProcessMessage func(msg *sarama.ConsumerMessage) error
-	// ShutdownCallback is called when ProcessMessage returns ErrShutdown, after the partition has been saved.
-	// It is optional.
-	ShutdownCallback func()
-}
-
-// ErrShutdown can be returned from ContinualConsumer.ProcessMessage to stop the ContinualConsumer.
-var ErrShutdown = fmt.Errorf("shutdown")
-
-// Start starts the consumer consuming.
-// Starts up a goroutine for each partition in the kafka stream.
-// Returns nil once all the goroutines are started.
-// Returns an error if it can't start consuming for any of the partitions.
-func (c *ContinualConsumer) Start() error {
-	_, err := c.StartOffsets()
-	return err
-}
-
-// StartOffsets is the same as Start but returns the loaded offsets as well.
-func (c *ContinualConsumer) StartOffsets() ([]sqlutil.PartitionOffset, error) {
-	offsets := map[int32]int64{}
-
-	partitions, err := c.Consumer.Partitions(c.Topic)
-	if err != nil {
-		return nil, err
-	}
-	for _, partition := range partitions {
-		// Default all the offsets to the beginning of the stream.
-		offsets[partition] = sarama.OffsetOldest
-	}
-
-	storedOffsets, err := c.PartitionStore.PartitionOffsets(context.TODO(), c.Topic)
-	if err != nil {
-		return nil, err
-	}
-	for _, offset := range storedOffsets {
-		// We've already processed events from this partition so advance the offset to where we got to.
-		// ConsumePartition will start streaming from the message with the given offset (inclusive),
-		// so increment 1 to avoid getting the same message a second time.
-		offsets[offset.Partition] = 1 + offset.Offset
-	}
-
-	var partitionConsumers []sarama.PartitionConsumer
-	for partition, offset := range offsets {
-		pc, err := c.Consumer.ConsumePartition(c.Topic, partition, offset)
-		if err != nil {
-			for _, p := range partitionConsumers {
-				p.Close() // nolint: errcheck
-			}
-			return nil, err
-		}
-		partitionConsumers = append(partitionConsumers, pc)
-	}
-	for _, pc := range partitionConsumers {
-		go c.consumePartition(pc)
-		if c.Process != nil {
-			c.Process.ComponentStarted()
-			go func(pc sarama.PartitionConsumer) {
-				<-c.Process.WaitForShutdown()
-				_ = pc.Close()
-				c.Process.ComponentFinished()
-				logrus.Infof("Stopped consumer for %q topic %q", c.ComponentName, c.Topic)
-			}(pc)
-		}
-	}
-
-	return storedOffsets, nil
-}
-
-// consumePartition consumes the room events for a single partition of the kafkaesque stream.
-func (c *ContinualConsumer) consumePartition(pc sarama.PartitionConsumer) {
-	defer pc.Close() // nolint: errcheck
-	for message := range pc.Messages() {
-		msgErr := c.ProcessMessage(message)
-		// Advance our position in the stream so that we will start at the right position after a restart.
-		if err := c.PartitionStore.SetPartitionOffset(context.TODO(), c.Topic, message.Partition, message.Offset); err != nil {
-			panic(fmt.Errorf("the ContinualConsumer in %q failed to SetPartitionOffset: %w", c.ComponentName, err))
-		}
-		// Shutdown if we were told to do so.
-		if msgErr == ErrShutdown {
-			if c.ShutdownCallback != nil {
-				c.ShutdownCallback()
-			}
-			return
-		}
-	}
-}