watermill-rediszset

README

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Watermill Redis Sorted Set Pub/Sub

This is Pub/Sub for the Watermill project.

Watermill is a Go library for working efficiently with message streams. It is intended for building event driven applications, enabling event sourcing, RPC over messages, sagas and basically whatever else comes to your mind. You can use conventional pub/sub implementations like Kafka or RabbitMQ, but also HTTP or MySQL binlog if that fits your use case.

Usage

Since redis zset is not a traditional message queue, two modes are adopted in the implementation to meet daily needs.

go get

go get -u github.com/stong1994/watermill-rediszset

Publish

    subscriber, _ := rediszset.NewSubscriber(
        rediszset.SubscriberConfig{
            Client:          client,
        },
        watermill.NewStdLogger(false, false),
    )
    messages, _ := subscriber.Subscribe(context.Background(), topic)
    for msg := range messages {
        fmt.Println(string(msg.Payload))
    }

Since redis zset needs to pass additional score, rediszset.NewMessage needs to be used to create a dedicated Message .

Consume

Normal mode

Usage:

    subscriber, _ := rediszset.NewSubscriber(
        rediszset.SubscriberConfig{
            Client:          client,
        },
        watermill.NewStdLogger(false, false),
    )
    messages, _ := subscriber.Subscribe(context.Background(), topic)
    for msg := range messages {
        fmt.Println(string(msg.Payload))
    }

In Normal mode, the consumer uses zpopmin to consume the data with the lowest score, which means that once the consumption process fails, the data will be lost. Therefore, we also support another more strict mode.

Strict mode

    subscriber, err := rediszset.NewStrictSubscriber(
        rediszset.StrictSubscriberConfig{
            Client:       client,
        },
        locker,
        watermill.NewStdLogger(true, false),
    )

In Strict mode, the consumer uses zrangewithscores to get the lowest-scored data. Once the business code ACK s the Message , the consumer will execute zrem to delete the data. If the business code NAck s the Message , the consumer will not execute zrem .

In Strict mode, since the data is still in redis when consuming data, it may cause duplicate consumption, and locker is required to lock the data.

License

MIT License