f0e6461cb6
The previous pipeline model required a lot of setup and abstracted away the processing of records. By passing a HandlerFunc to the consumer we keep the business logic of processing of records closer to the use of the consumer. * Add refactoring note and SHA to README
48 lines
1.4 KiB
Go
48 lines
1.4 KiB
Go
package connector
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import (
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"fmt"
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"github.com/hoisie/redis"
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)
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// RedisCheckpoint implements the Checkpont interface.
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// This class is used to enable the Pipeline.ProcessShard to checkpoint their progress.
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type Checkpoint struct {
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AppName string
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StreamName string
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client redis.Client
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sequenceNumber string
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}
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// CheckpointExists determines if a checkpoint for a particular Shard exists.
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// Typically used to determine whether we should start processing the shard with
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// TRIM_HORIZON or AFTER_SEQUENCE_NUMBER (if checkpoint exists).
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func (c *Checkpoint) CheckpointExists(shardID string) bool {
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val, _ := c.client.Get(c.key(shardID))
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if val != nil && string(val) != "" {
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c.sequenceNumber = string(val)
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return true
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}
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return false
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}
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// SequenceNumber returns the current checkpoint stored for the specified shard.
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func (c *Checkpoint) SequenceNumber() string {
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return c.sequenceNumber
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}
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// SetCheckpoint stores a checkpoint for a shard (e.g. sequence number of last record processed by application).
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// Upon failover, record processing is resumed from this point.
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func (c *Checkpoint) SetCheckpoint(shardID string, sequenceNumber string) {
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c.client.Set(c.key(shardID), []byte(sequenceNumber))
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c.sequenceNumber = sequenceNumber
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}
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// key generates a unique Redis key for storage of Checkpoint.
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func (c *Checkpoint) key(shardID string) string {
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return fmt.Sprintf("%v:checkpoint:%v:%v", c.AppName, c.StreamName, shardID)
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}
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