# Redis: Streams
A Redis stream is a data structure that acts like an append-only log but also implements several operations to overcome some of the limits of a typical append-only log. We can use streams to record and simultaneously syndicate events in real time.
* Redis generates a unique ID for each stream entry.
* Streams keep messages in Redis for as long as you want (configurable).
* Consumers can read at their own pace, even if they were offline.
* We can acknowledge messages (`XACK`) and track delivery.
Similar like pub/sub we need A producer and consumers to implement redis streams in our system.
## Basic Example
Lets create a basic example of redis streams using `XADD` and `XREAD` command.
### Setup
To run redis server you can install it directly in your machine or using virtualization. For me I prefer to use docker and here is how to do it.
Run a detached container with name `my-redis` using latest `redis` image and expose the port `6379`.
```bash
docker run -d -p 6379:6379 --name my-redis redis
```
Run `redis-cli` inside the newly created redis container.
```bash
➜ redis_streams docker exec -it my-redis redis-cli
127.0.0.1:6379>
```
### `XADD`
This is the simplest form of adding a message to a Redis Stream. Each message will have a unique ID and some data fields.
```bash
127.0.0.1:6379> XADD mystream * message Hello
"1740039025432-0"
```
* `mystream`: name of the stream, redis will create the stream if not exist.
* `*`: Stream ID, will auto-generate a unique ID if the ID argument specified is the `*`.
* `message Hello`: Key value pair data, `message` is the key and value is `Hello`.
### `XREAD`
Read data from one or multiple streams. This command has an option to block if items are not available.
```bash
127.0.0.1:6379> XREAD COUNT 1 STREAMS mystream 0
1) 1) "mystream"
2) 1) 1) "1740039025432-0"
2) 1) "message"
2) "Hello"
```
* `COUNT 1`: Return maximum 1 element for each stream.
* `STREAMS mystream 0`:
* `mystream`: Name of the stream.
* `0`: Read element from the start.
## References
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