Add NATS How To (#239)

howto/setup-pub-sub-message-broker/README.md

@@ -43,3 +43,4 @@ kubectl apply -f pubsub.yaml
 ## Reference
 
 [Setup Redis Streams](./setup-redis.md)
+[Setup NATS](./setup-nats.md)

howto/setup-pub-sub-message-broker/setup-nats.md

@@ -0,0 +1,62 @@
+# Setup NATS 
+
+## Locally
+
+You can run a NATS server locally using Docker:
+
+```
+docker run -d --name nats-main -p 4222:4222 -p 6222:6222 -p 8222:8222 nats
+```
+
+You can then interact with the server using the client port: `localhost:4222`.
+
+## Kubernetes
+
+The easiest way to install NATS on Kubernetes is by using the [Helm chart](https://github.com/helm/charts/tree/master/stable/nats):
+
+```
+helm install --name nats stable/nats
+```
+
+This will install NATS into the `default` namespace.
+To interact with NATS, find the service with: `kubectl get svc nats-client`.
+
+For example, if installing using the example above, the NATS server client address would be:
+
+`nats-client.default.svc.cluster.local:4222`
+
+## Create a Dapr component
+
+The next step is to create a Dapr component for NATS.
+
+Create the following YAML file named `nats.yaml`:
+
+```
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: <name>
+spec:
+  type: pubsub.nats
+  metadata:
+  - name: natsURL
+    value: <REPLACE-WITH-NATS-SERVER-ADDRESS> # Required. Example: "nats-client.default.svc.cluster.local:4222"
+```
+
+The above example uses secrets as plain strings. It is recommended to use a secret store for the secrets as described [here](../../concepts/components/secrets.md)
+
+
+## Apply the configuration
+
+### In Kubernetes
+
+To apply the NATS pub/sub to Kubernetes, use the `kubectl` CLI:
+
+```
+kubectl apply -f nats.yaml
+```
+
+### Running locally
+
+The Dapr CLI will automatically create a directory named `components` in your current working directory with a Redis component.
+To use NATS, replace the redis_messagebus.yaml file with nats.yaml above.