59f488e6c7
Match the Golang std library style of adding line-breaks after exported fields. http://golang.org/src/pkg/sync/cond.go?s=609:772#L12
47 lines
1.4 KiB
Go
47 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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// A Redis implementation of the Checkpont interface. This class is used to enable the Pipeline.ProcessShard
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// to checkpoint their progress.
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type RedisCheckpoint 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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// Check whether a checkpoint for a particular Shard exists. Typically used to determine whether we should
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// start processing the shard with TRIM_HORIZON or AFTER_SEQUENCE_NUMBER (if checkpoint exists).
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func (c *RedisCheckpoint) 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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} else {
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return false
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}
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}
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// Get the current checkpoint stored for the specified shard.
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func (c *RedisCheckpoint) SequenceNumber() string {
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return c.sequenceNumber
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}
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// Record 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 *RedisCheckpoint) 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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// Generate a unique Redis key for storage of Checkpoint.
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func (c *RedisCheckpoint) 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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