Minimal redis stream source doc (#5253)

* minimal redis stream source doc

* Update docs/eventing/sources/redis/README.md

* Update docs/eventing/sources/redis/getting-started.md

* Update docs/eventing/sources/redis/getting-started.md

Co-authored-by: Ashleigh Brennan <abrennan@redhat.com>

config/nav.yml

@@ -183,6 +183,9 @@ nav:
             - Creating a PingSource object: eventing/sources/ping-source/README.md
             - PingSource reference: eventing/sources/ping-source/reference.md
           - RabbitMQSource: eventing/sources/rabbitmq-source/README.md
+          - RedisStreamSource:
+            - About RedisStreamSource: eventing/sources/redis/README.md
+            - Creating a RedisStreamSource object: eventing/sources/redis/getting-started.md
         # BYO event source
         - Custom event sources:
           - Custom event sources overview: eventing/custom-event-source/README.md

docs/eventing/sources/apiserversource/README.md

@@ -1,4 +1,4 @@
-# ApiServerSource
+# About ApiServerSource
 
 ![stage](https://img.shields.io/badge/Stage-stable-green?style=flat-square)
 ![version](https://img.shields.io/badge/API_Version-v1-green?style=flat-square)

docs/eventing/sources/redis/README.md

@@ -0,0 +1,6 @@
+# About RedisStreamSource
+
+![stage](https://img.shields.io/badge/Stage-alpha-green?style=flat-square)
+![version](https://img.shields.io/badge/API_Version-v1alpha1-red?style=flat-square)
+
+The RedisStreamSource reads messages from [Redis Streams](https://redis.io/docs/data-types/streams/) and sends them as CloudEvents to the referenced Sink.

docs/eventing/sources/redis/getting-started.md

@@ -0,0 +1,104 @@
+# Creating a RedisStreamSource
+
+![version](https://img.shields.io/badge/API_Version-v1alpha1-red?style=flat-square)
+
+This topic describes how to create a `RedisStreamSource` object.
+
+## Install the RedisStreamSource add-on
+
+`RedisStreamSource` is a Knative Eventing add-on.
+
+1. Install RedisStreamSource by running the command:
+
+    ```bash
+    kubectl apply -f {{ artifact(org="knative-sandbox", repo="eventing-redis", file="redis-source.yaml") }}
+    ```
+
+1. Verify that `redis-controller-manager`is running:
+
+    ```bash
+    kubectl get deployments.apps -n knative-sources
+    ```
+
+    Example output:
+
+    ```{ .bash .no-copy }
+    NAME                           READY   UP-TO-DATE   AVAILABLE   AGE
+    redis-controller-manager        1/1     1            1           3s
+    ```
+
+{% include "event-display.md" %}
+
+## Create a RedisStreamSource object
+
+1. Create the `RedisStreamSource` object using the YAML template below:
+
+  ```yaml
+  apiVersion: sources.knative.dev/v1alpha1
+  kind: RedisStreamSource
+  metadata:
+    name: <redis-stream-source>
+  spec:
+    address: <redis-uri>
+    stream: <redis-stream-name>
+    group: <consumer-group-name>
+    sink: <sink>
+  ```
+
+Where:
+
+* `<redis-stream-source>` is the name of your source. (required)
+* `<redis-uri>` is the Redis URI. See the [Redis documentation](https://redis.io/docs/manual/cli/#host-port-password-and-database) for more information. (required)
+* `<redis-stream-name>` is the name of the Redis stream. (required)
+* `<consumer-group-name>` is the name of the Redis consumer group. When left empty a group
+   is automatically created for this source, and deleted when this source is deleted. (optional)
+* `<sink>` is where to send events. (required)
+
+1. Apply the YAML file by running the command:
+
+    ```bash
+    kubectl apply -f <filename>
+    ```
+
+    Where `<filename>` is the name of the file you created in the previous step.
+
+## Verify the RedisStreamSource object
+
+1. View the logs for the `event-display` event consumer by running the command:
+
+    ```bash
+    kubectl logs -l app=event-display --tail=100
+    ```
+
+    Sample output:
+
+    ```{ .bash .no-copy }
+    ☁️  cloudevents.Event
+    Validation: valid
+    Context Attributes,
+      specversion: 1.0
+      type: dev.knative.sources.redisstream
+      source: /mystream
+      id: 1597775814718-0
+      time: 2020-08-18T18:36:54.719802342Z
+      datacontenttype: application/json
+    Data,
+      [
+        "fruit",
+        "banana"
+        "color",
+        "yellow"
+      ]
+    ```
+
+## Delete the RedisStreamSource object
+
+* Delete the `RedisStreamSource` object:
+
+    ```bash
+    kubectl delete -f <filename>
+    ```
+
+## Additional information
+
+* For more information about Redis Stream source, see the [`eventing-redis` Github repository](https://github.com/knative-sandbox/eventing-redis/tree/main/config/source)