Add how-to guide on Connect to dependencies

.github/config/en-custom.txt

@@ -947,5 +947,6 @@ PodSpec
 ConfigMap
 CRD
 composable
+mycontainer
 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 +1,89 @@
+---
+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: Model an app and container
+
+Create a new file named `app.bicep` and add a [container]({{< ref "guides/author-apps/containers" >}}):
+
+{{< rad file="snippets/app.bicep" embed=true >}}
+
+## Step 2: Add a Mongo database as a dependency
+
+Next, add to `app.bicep` a [Mongo database]({{< ref "/guides/author-apps/portable-resources/overview" >}}), leveraging the default "local-dev" Recipe:
+
+{{< rad file="snippets/app-mongodb.bicep" embed=true marker="//DB" >}}
+
+## Step 3: Connect to the Mongo database
+
+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 Mongo database:
+
+{{< rad file="snippets/app-mongodb.bicep" embed=true marker="//CONTAINER" markdownConfig="{linenos=table,hl_lines=[\"8-12\"],linenostart=7}" >}}
+
+## Step 4: Deploy your app
+
+1. Run your application in your environment:
+
+   ```bash
+   rad run ./app.bicep -a myapp
+   ```
+1. Visit [localhost:5000](http://localhost:5000) in your browser. You should see the following page, now showing injected environment variables:
+
+   <img src="./connections.png" alt="Screenshot of the app printing all the 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 `mycontainer` and the `db` Mongo database, along with information about the underlying Kubernetes resources running the app:
+
+```
+Displaying application: myapp
+
+Name: mycontainer (Applications.Core/containers)
+Connections:
+  mycontainer -> mongo-db (Applications.Datastores/mongoDatabases)
+Resources:
+  mycontainer (kubernetes: apps/Deployment)
+  mycontainer (kubernetes: core/Secret)
+  mycontainer (kubernetes: core/ServiceAccount)
+  mycontainer (kubernetes: rbac.authorization.k8s.io/Role)
+  mycontainer (kubernetes: rbac.authorization.k8s.io/RoleBinding)
+
+Name: mongo-db (Applications.Datastores/mongoDatabases)
+Connections:
+  mycontainer (Applications.Core/containers) -> mongo-db
+Resources:
+  mongo-xxx(kubernetes: apps/Deployment)
+  mongo-xxx(kubernetes: core/Service)
+```
+
+## Cleanup
+
+Run `rad app delete` to cleanup your Radius application, container, and mongo database:
+
+```bash
+rad app delete -a myapp
+```
+
+## Further reading
+
+- [Connections]({{< ref "guides/author-apps/containers/overview#connections" >}})
+- [Container schema]({{< ref container-schema >}})

docs/content/guides/author-apps/containers/howto-environment-variables/snippets/3-app.bicep → docs/content/guides/author-apps/containers/howto-connect-dependencies/snippets/app-mongodb.bicep

@@ -1,25 +1,15 @@
 import radius as rad
 
-param environment string
-
-resource app 'Applications.Core/applications@2023-10-01-preview' = {
-  name: 'myapp'
-  properties: {
-    environment: environment
-  }
-}
+@description('The app ID of your Radius application. Set automatically by the rad CLI.')
+param application string
 
 //CONTAINER
 resource container 'Applications.Core/containers@2023-10-01-preview' = {
   name: 'mycontainer'
   properties: {
-    application: app.id
+    application: application
     container: {
       image: 'radius.azurecr.io/quickstarts/envvars:edge'
-      env: {
-        FOO: 'BAR'
-        BAZ: app.name
-      }
     }
     connections: {
       myconnection: {
@@ -30,13 +20,16 @@ resource container 'Applications.Core/containers@2023-10-01-preview' = {
 }
 //CONTAINER
 
-//LINK
+//DB
+@description('The environment ID of your Radius application. Set automatically by the rad CLI.')
+param environment string
+
 resource mongoDatabase 'Applications.Datastores/mongoDatabases@2023-10-01-preview' = {
   name: 'mongo-db'
   properties: {
     environment: environment
-    application: app.id
+    application: application
     // Use the "default" Recipe to provision the MongoDB
   }
 }
-//LINK
+//DB

docs/content/guides/author-apps/containers/howto-environment-variables/snippets/1-app.bicep → docs/content/guides/author-apps/containers/howto-connect-dependencies/snippets/app.bicep

@@ -1,18 +1,12 @@
 import radius as rad
 
-param environment string
-
-resource app 'Applications.Core/applications@2023-10-01-preview' = {
-  name: 'myapp'
-  properties: {
-    environment: environment
-  }
-}
+@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: 'mycontainer'
   properties: {
-    application: app.id
+    application: application
     container: {
       image: 'radius.azurecr.io/quickstarts/envvars:edge'
     }

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

@@ -103,7 +103,7 @@ 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. Refer to the [connect to dependencies how-to guide]({{< ref howto-connect-dependencies >}}) for more details.
 
 ## Extensions