Add how-to guide on Connect to dependencies

.github/config/en-custom.txt

@@ -948,4 +948,4 @@ ConfigMap
 CRD
 composable
 gatewaydemo
-tlsdemo
+tlsdemo

docs/config.toml

@@ -62,7 +62,6 @@ tag = "tags"
 
 [params]
 copyright = "Radius"
-
 version = "edge"
 tag_version = "latest"
 chart_version = "0.19.0"

docs/content/guides/author-apps/containers/howto-connect-dependencies/index.md

@@ -0,0 +1,90 @@
+---
+type: docs
+title: "How-To: Connect to dependencies"
+linkTitle: "Connect to dependencies"
+description: "Learn how to connect to dependencies in your application via connections"
+weight: 200
+categories: "How-To"
+tags: ["containers"]
+---
+
+This how-to guide will teach how to connect to your dependencies via [connections]({{< ref "guides/author-apps/containers#connections" >}})
+
+## Prerequisites
+
+- [Radius CLI]({{< ref "installation#step-1-install-the-rad-cli" >}})
+- [Radius environment]({{< ref "installation#step-3-initialize-the-radius-control-plane-and-the-radius-environment" >}})
+
+## Step 1: View the container definition
+
+Open the `app.bicep` and view the [container]({{< ref "guides/author-apps/containers" >}}):
+
+{{< rad file="snippets/app.bicep" embed=true >}}
+
+## Step 2: Add a Redis cache as a dependency
+
+Next, add to `app.bicep` a [Redis cache]({{< ref "/guides/author-apps/portable-resources/overview" >}}), leveraging the default "local-dev" Recipe:
+
+{{< rad file="snippets/app-with-redis.bicep" embed=true marker="//DB" >}}
+
+## Step 3: Connect to the Redis cache
+
+Connections from a container to a resource result in environment variables for connection information automatically being set on the container. Update your container definition to add a connection to the new Redis cache:
+
+{{< rad file="snippets/app-with-redis.bicep" embed=true marker="//CONTAINER" markdownConfig="{linenos=table,hl_lines=[\"13-17\"],linenostart=7}" >}}
+
+## Step 4: Deploy your app
+
+1. Run your application in your environment:
+
+   ```bash
+   rad run ./app.bicep 
+   ```
+1. Visit [localhost:3000](http://localhost:3000) in your browser. You should see the following page, now showing injected environment variables:
+
+   <img src="./demo-with-redis-screenshot.png" alt="Screenshot of the demo app with all environment variables" width=1000px />
+
+## Step 5: View the application connections
+
+Radius connections are more than just environment variables and configuration. You can also access the "application graph" and understand the connections within your application with the following command:
+
+```bash
+rad app connections
+```
+
+You should see the following output, detailing the connections between the `demo` container and the `db` Redis cache, along with information about the underlying Kubernetes resources running the app:
+
+```
+Displaying application: demo
+
+Name: demo (Applications.Core/containers)
+Connections:
+  demo -> db (Applications.Datastores/redisCaches)
+Resources:
+  demo (kubernetes: apps/Deployment)
+  demo (kubernetes: core/Secret)
+  demo (kubernetes: core/Service)
+  demo (kubernetes: core/ServiceAccount)
+  demo (kubernetes: rbac.authorization.k8s.io/Role)
+  demo (kubernetes: rbac.authorization.k8s.io/RoleBinding)
+
+Name: db (Applications.Datastores/redisCaches)
+Connections:
+  demo (Applications.Core/containers) -> db
+Resources:
+  redis-r5tcrra3d7uh6 (kubernetes: apps/Deployment)
+  redis-r5tcrra3d7uh6 (kubernetes: core/Service)
+```
+
+## Cleanup
+
+Run `rad app delete` to cleanup your Radius application, container, and Redis cache:
+
+```bash
+rad app delete -a demo
+```
+
+## Further reading
+
+- [Connections]({{< ref "guides/author-apps/containers/overview#connections" >}})
+- [Container schema]({{< ref container-schema >}})

docs/content/guides/author-apps/containers/howto-connect-dependencies/snippets/app-with-redis.bicep

@@ -0,0 +1,38 @@
+// Import the set of Radius resources (Applications.*) into Bicep
+import radius as radius
+
+@description('The app ID of your Radius application. Set automatically by the rad CLI.')
+param application string
+
+//CONTAINER
+resource demo 'Applications.Core/containers@2023-10-01-preview' = {
+  name: 'demo'
+  properties: {
+    application: application
+    container: {
+      image: 'radius.azurecr.io/samples/demo:latest'
+      ports: {
+        web: {
+          containerPort: 3000
+        }
+      }
+    }
+    connections: {
+      redis: {
+        source: db.id
+      }
+    }
+  }
+}
+//CONTAINER
+
+//DB
+param environment string
+resource db 'Applications.Datastores/redisCaches@2023-10-01-preview' = {
+  name: 'db'
+  properties: {
+    application: application
+    environment: environment
+  }
+}
+//DB

docs/content/guides/author-apps/containers/howto-connect-dependencies/snippets/app.bicep

@@ -0,0 +1,14 @@
+import radius as rad
+
+@description('The app ID of your Radius application. Set automatically by the rad CLI.')
+param application string
+
+resource container 'Applications.Core/containers@2023-10-01-preview' = {
+  name: 'demo'
+  properties: {
+    application: application
+    container: {
+      image: 'radius.azurecr.io/samples/demo:latest'
+    }
+  }
+}

docs/content/guides/author-apps/containers/overview/index.md

@@ -103,7 +103,9 @@ For example, adding a connection called `database` that connects to a MongoDB re
 | `CONNECTION_DATABASE_USERNAME` | Username of the target database |
 | `CONNECTION_DATABASE_PASSWORD` | Password of the target database |
 
-Alternatively, if you already have another convention you would like to follow or if you just prefer to be explicit, you may ignore the values generated by a connection and instead override it by setting your own environment variable values. Refer to the [environment variables how-to guide]({{< ref howto-environment-variables >}}) for more details.
+Alternatively, if you already have another convention you would like to follow or if you just prefer to be explicit, you may ignore the values generated by a connection and instead override it by setting your own environment variable values. 
+
+<!-- For more information on how to add connections, refer to the [connect to dependencies how-to guide]("guides/author-apps/containers/how-to-connect-dependencies"). -->
 
 ## Extensions