realm-template-apps

This is the main repo for all MongoDB App Services & Realm template starter app clients and backend configurations.

A GitHub Action uploads to the realm-template-apps S3 bucket. See .github/workflows/zip-everything-and-upload-to-s3.yml.

For bucket access, consult the Realm docs team.

Warning

As of September 2024, Atlas Device SDKs are deprecated. Atlas Device SDKs will reach end-of-life and will no longer be maintained by MongoDB on September 30, 2025.

The template apps in this repository should only be used as a reference for the on-device database and not to create a new app based on Device Sync. Refer to the deprecation page for details.

Lay of the Land

• manifest.json: Tells the App Services server which templates correspond to which backends and various other configuration details. This must be updated whenever you want to expose a new app or move anything around.
• sync-todo/: The template app. Even though App Services can tie any app from this repo into the template app infrastructure, when people refer to "the template app", they usually mean this one. Comes in many clients and has had many versions.
• other/: All other apps.
• tools/: Useful things for working within this repo.

Sync-todo Versions

• v2: (Current) A todo app with a flexible sync backend that has a few new nifty features.

About "generated"

⚠️ If the path contains /generated/, don't edit it directly! This is generated from another source, probably using Bluehawk.

Artifact Repos

A GitHub Action creates "artifact repos" of a few subdirectories so that the client code can be examined and cloned easily.

• https://github.com/mongodb/template-app-cpp-todo
• https://github.com/mongodb/template-app-dart-flutter-todo
• https://github.com/mongodb/template-app-kotlin-todo
• https://github.com/mongodb/template-app-maui-todo
• https://github.com/mongodb/template-app-react-native-todo
• https://github.com/mongodb/template-app-swiftui-todo
• https://github.com/mongodb/template-app-edge-server

Adding a New Template App

1. Add your project in its own subdirectory. If you are basing your project off of an existing project (for example, creating a Flexible-Sync version of a partition-based app), consider using the Bluehawk state tags and using Bluehawk to copy each app to its own subdirectory within the generated directory.

2. Be sure your project uses a realm.json file (or .xml, or .plist...) to get the app id, base url info, and data explorer link:

   {
      "appId": "todo-sync-jxgjv",
      "baseUrl": "https://services.cloud.mongodb.com",
      "dataExplorerLink": "https://cloud.mongodb.com/links/app_id/explorer/cluster_name/database/collection/find"
   }
   

   Note that these values will be updated by the script that links the Realm UI to each template app. The location of this file should make sense to your app (and its users) -- you just need to let the build trigger know where it is, which you do in the next step.

3. Update the manifest.json file that lives in the root of this repo to add a new object to the manifest. Each object has this shape:

   "<my.project.id>": { <-- change to your unique ID
    "name": "The.Title.Of.My.App",
    "repo_owner": "mongodb-university", <-- don't change
    "repo_name": "realm-template-apps", <-- don't change
    "backend_path": "see the notes below",
    "client_path": "my-project-subdirectory-name",
    "metadata_path": "path-to-the-directory-that-contains-your-realm.json-file",
    "metadata_filename": "realm",
    "file_format": "json"
   },
   
   

   Each key in the manifest is the unique ID of the template. No spaces are allowed. Should ideally be somewhat typeable as users have the option of manually pulling templates via the realm-cli (i.e. realm-cli pull --template=some-template-id)

   • name: A friendly name. Presented in the UI or when listing available templates from the CLI.
   • repo_owner, repo_name: This repo's upstream. Just use mongodb-university and realm-template-apps respectively.
   • backend_path: The relative path from the root of this repo to the backend app to import when instantiating the template.
   • client_path: (optional). The relative path from the root of this repo to the client app source directory to be copied when instantiating the template.

   metadata_path, metadata_filename, and file_format are all required if client_path is set. When Realm instantiates the template, it adds the generated backend app ID (and base URL) to a file that the instantiated client then reads to know which backend app to use.

   • metadata_path: The relative path from the root of this repo to the directory where your client reads the Realm metadata file.
   • metadata_filename: The actual name of the Realm metadata file. Probably "Realm" or "realm".
   • file_format: One of "json", "xml", or "plist" -- whichever your client knows how to read. App Services produces a metadata file with the given file_format as file extension in the format specified.

4. When you merge your branch, a Github action zips everything up and uploads to an S3 bucket. Upon the next reload of App Services (usually around release time but can be requested any time), App Services pulls the zip file down and makes the templates within available to the CLI.

   The product team decides which templates actually show up in the UI.

   In short: when you merge your changes to the repo, the UI will not expose this template immediately. You should be safe to work on this template at your leisure. However, people can create apps with this template via the cli soon after you merge.

Tips & Tricks

Many of the template source directories now follow this structure:

• backend: The backend configuration.
• client: The client(s) source code.
• generated: Contains generated code. Don't edit this directly!
• bluehawk.sh: Generally bluehawks whatever's in client/ and puts it in generated/. This keeps the client source clean when consumed by the backend or viewed on an artifact repo.
• realm-template.{json|xml|plist}: Copied after bluehawking to the client(s) in the generated directory. This scrubs the app ID used in development.