feat: Add a new doc covering entities context

- New doc: "Attach your Nerdlet to entities"
- Reference in "Serve your New Relic One application"

src/data/nav.yml

@@ -56,6 +56,8 @@
       url: '/build-apps/publish-deploy'
     - title: Permissions for managing apps
       url: '/build-apps/permission-manage-apps'
+    - title: Attach your Nerdlet to your entities
+      url: '/build-apps/attach-nerdlet-to-entities'
     - title: Map pageviews by region
       url: '/build-apps/map-pageviews-by-region'
     - title: Add a time picker

src/markdown-pages/build-apps/attach-nerdlet-to-entities.mdx

@@ -0,0 +1,359 @@
+---
+path: '/build-apps/attach-nerdlet-to-entities'
+title: 'Attach your Nerdlet to entities'
+template: 'GuideTemplate'
+description: 'Attach your Nerdlet to entities'
+---
+
+<Intro>
+
+One way for users to access your Nerdlet is by creating a launcher. The launcher opens a Nerdlet from the **Apps** page in New Relic. You can also provide access to your Nerdlet from an [entity](https://docs.newrelic.com/docs/new-relic-one/use-new-relic-one/core-concepts/what-entity-new-relic/) in your account.
+
+In this guide, you'll learn how to attach your Nerdlet to your entities.
+
+</Intro>
+
+## Before you begin
+
+If you haven't already:
+
+- [Sign up](https://newrelic.com/signup/) for a New Relic account
+- [Install and configure the New Relic One CLI](https://one.newrelic.com/launcher/developer-center.launcher?pane=eyJuZXJkbGV0SWQiOiJkZXZlbG9wZXItY2VudGVyLmRldmVsb3Blci1jZW50ZXIifQ==)
+
+## Create a Nerdpack
+
+<Steps>
+
+<Step>
+
+Create a Nerdpack with the CLI:
+
+```sh
+nr1 create --type nerdpack --name entity-nerdlet
+```
+
+This results in a Nerdpack, called `entity-nerdlet`, which consists of a launcher, called `entity-nerdlet-launcher`, and a Nerdlet, called `entity-nerdlet-nerdlet`.
+
+</Step>
+
+<Step>
+
+[Serve](https://developer.newrelic.com/build-apps/publish-deploy/serve/) your Nerdpack:
+
+```sh
+cd entity-nerdlet
+nr1 nerdpack:serve
+```
+
+</Step>
+
+<Step>
+
+Go to [https://one.newrelic.com/?nerdpacks=local](https://one.newrelic.com/?nerdpacks=local) and navigate to **Apps**:
+
+![Navigate to Apps](../../images/ab-test/nav-to-apps.png)
+
+`?nerdpacks=local` is required to enable your locally served Nerdpacks to load in New Relic.
+
+</Step>
+
+<Step>
+
+Under **Your apps**, click your launcher to view your New Relic One application:
+
+![Click entity-nerdlet launcher](../../images/build-an-app/entity-nerdlet.png)
+
+</Step>
+
+</Steps>
+
+## Attach your Nerdlet to entities
+
+You've seen how you can access your Nerdlet from a launcher. Now, access your Nerdlet from your entities.
+
+<Tutorial>
+
+<Project>
+
+```json fileName=nerdlets/entity-nerdlet-nerdlet/nr1.json
+{
+    "schemaType": "NERDLET",
+    "id": "entity-nerdlet-nerdlet",
+    "displayName": "EntityNerdletNerdlet",
+    "description": ""
+}
+```
+
+</Project>
+
+<Steps>
+
+<Step>
+
+From inside your Nerdpack's root directory, open _nerdlets/entity-nerdlet-nerdlet/nr1.json_. This is your Nerdlet's metadata file. You'll use this file to attach your Nerdlet to entities.
+
+</Step>
+
+<Step>
+
+Add a `context` object with an `entities` array:
+
+```json fileName=nerdlets/entity-nerdlet-nerdlet/nr1.json
+{
+    "schemaType": "NERDLET",
+    "id": "entity-nerdlet-nerdlet",
+    "displayName": "EntityNerdletNerdlet",
+    "description": "",
+    "context": {
+        "entities": [
+        ]
+    }
+}
+```
+
+This tells New Relic that you want to surface your Nerdlet in an array of entity contexts.
+
+</Step>
+
+<Step>
+
+Add an entity context:
+
+```json fileName=nerdlets/entity-nerdlet-nerdlet/nr1.json
+{
+    "schemaType": "NERDLET",
+    "id": "entity-nerdlet-nerdlet",
+    "displayName": "EntityNerdletNerdlet",
+    "description": "",
+    "context": {
+        "entities": [
+            {
+                "domain": "APM",
+                "type": "APPLICATION"
+            }
+        ]
+    }
+}
+```
+
+Here, you've attached your Nerdlet to all _application_ entities in the _APM_ domain.
+
+</Step>
+
+<Step>
+
+Go to **APM**:
+
+![Navigate to APM](../../images/build-an-app/nav-to-apm.png)
+
+Because you're serving your Nerdpack locally, remember that you must still specify the `?nerdpacks=local` query string.
+
+</Step>
+
+<Step>
+
+Choose any of your applications:
+
+![Navigate to APM application](../../images/build-an-app/nav-to-apm-service.png)
+
+</Step>
+
+<Step>
+
+Scroll down to see your Nerdlet attached to the application:
+
+![Your Nerdlet attached to the application views](../../images/build-an-app/nerdlet-attached-to-app.png)
+
+Click this menu option and see your Nerdlet the same way you did with the launcher.
+
+</Step>
+
+</Steps>
+
+</Tutorial>
+
+## Configure your `entities` context
+
+The `context.entities` key in your Nerdlet's _nr1.json_ file specifies which entities your Nerdlet should be attached to.
+
+### Specify an entity `domain`
+
+Attach your Nerdlet to a certain entity domain by specifying the `domain` as one of the following values:
+
+- `APM`: [Application Performance Monitoring](https://docs.newrelic.com/docs/apm/)
+- `BROWSER`: [Browser](https://docs.newrelic.com/docs/browser/)
+- `INFRA`: [Infrastructure monitoring](https://docs.newrelic.com/docs/infrastructure/)
+- `MOBILE`: [Mobile monitoring](https://docs.newrelic.com/docs/mobile-monitoring/)
+- `SYNTH`: [Synthetic monitoring](https://docs.newrelic.com/docs/synthetics/)
+
+For example, attach your Nerdlet to all entities in the `APM` domain:
+
+```json
+{
+    "context": {
+        "entities": [
+            {"domain": "APM"}
+        ]
+    }
+}
+```
+
+Attach your Nerdlet to all entities _except_ those in a domain:
+
+```json
+{
+    "context": {
+        "entities": [
+            {"domain": "!APM"}
+        ]
+    }
+}
+```
+
+Attach your Nerdlet to all entities in multiple domains:
+
+```json
+{
+    "context": {
+        "entities": [
+            {"domain": "APM"},
+            {"domain": "BROWSER"}
+        ]
+    }
+}
+```
+
+### Specify an entity `type`
+
+Attach your Nerdlet to a certain entity type by specifying the `type` as one of the following values:
+
+- `APPLICATION`
+- `HOST`
+- `MONITOR`
+
+For example, attach your Nerdlet to all entities of the `APPLICATION` type:
+
+```json
+{
+    "context": {
+        "entities": [
+            {"type": "APPLICATION"}
+        ]
+    }
+}
+```
+
+Attach your Nerdlet to all entities _except_ those of a specified type:
+
+```json
+{
+    "context": {
+        "entities": [
+            {"type": "!APPLICATION"}
+        ]
+    }
+}
+```
+
+Attach your Nerdlet to every entity whose type matches one of an array of types:
+
+```json
+{
+    "context": {
+        "entities": [
+            {"type": "APPLICATION"},
+            {"type": "MONITOR"}
+        ]
+    }
+}
+```
+
+### Specify entity `tags`
+
+Attach your Nerdlet to entities that have a given [tag](https://docs.newrelic.com/docs/new-relic-one/use-new-relic-one/core-concepts/use-tags-help-organize-find-your-data/).
+
+For example, attach your Nerdlet to the entity which has a particular GUID:
+
+```json
+{
+    "context": {
+        "entities": [
+            {
+                "tags": [
+                    {
+                        "key": "guid",
+                        "values": [
+                            "<SOME ENTITY GUID>"
+                        ]
+                    }
+                ]
+            }
+        ]
+    }
+}
+```
+
+Attach your Nerdlet to every entity which has particular `accountId` _and_ uses the Python programming language:
+
+```json
+{
+    "context": {
+        "entities": [
+            {
+                "tags": [
+                    {
+                        "key": "accountId",
+                        "values": [
+                            "<SOME ACCOUNT ID>"
+                        ]
+                    },
+                    {
+                        "key": "language",
+                        "values": [
+                            "python"
+                        ]
+                    }
+                ]
+            }
+        ]
+    }
+}
+```
+
+### Combine filters
+
+When you filter the entities to which your Nerdlet will be added, you can combine `domain`, `type`, and `tags`:
+
+```json
+{
+    "context": {
+        "entities": [
+            {
+                "domain": "APM",
+                "type": "APPLICATION",
+                "tags": [
+                    {
+                        "key": "language",
+                        "values": [
+                            "python"
+                        ]
+                    }
+                ]
+            },
+            {
+                "domain": "SYNTH",
+                "type": "MONITOR"
+            },
+            {
+                "domain": "BROWSER"
+            }
+        ]
+    }
+}
+```
+
+In this example, you've attached your Nerdlet to:
+
+- All APM applications whose metadata tags specify the `python` language
+- **AND** all Synthetic monitors
+- **AND** all Browser entities

src/markdown-pages/build-apps/create-an-ab-test-application/serve-app.mdx

@@ -68,6 +68,12 @@ Select your launcher to see your root Nerdlet and its default welcome message:
 
 ![Your application's default welcome message](../../../images/ab-test/default-message.png)
 
+<Callout variant="tip">
+
+Here, you've seen how to access your Nerdlet from a launcher. If you want your Nerdlet closer to your data, you can also [attach your Nerdlet to New Relic entities](/build-apps/attach-nerdlet-to-entities#attach-your-nerdlet-to-entities).
+
+</Callout>
+
 </Step>
 
 </Steps>