Basic Looker Extension Template

This repository demonstrates a very basic extension (no react).

Getting Started for Development

1. Clone or download a copy of this template to your development machine

2. Navigate (cd) to the remplate directory on your system

3. Install the dependencies with Yarn.

   yarn install
   

   You may need to update your Node version or use a Node version manager to change your Node version.

4. Start the development server

   yarn start
   

   Great! Your extension is now running and serving the JavaScript at http://localhost:8080/bundle.js.

   Note well: The webpack development server also supports https. To use, add the parameter --https to the start command "start": "webpack-dev-server --hot --disable-host-check --https" Should you decide to use https, you should visit the bundle URL you are running as there will likely be a certificate warning. The development server runs with a self-signed SSL certificate, so you will need to accept this to allow your browser to connect to it.

5. Now log in to Looker and create a new project.

   This is found under Develop => Manage LookML Projects => New LookML Project.

   You'll want to select "Blank Project" as your "Starting Point". You'll now have a new project with no files.

6. In your copy of the extension tablet you have manifest.lkml file.

   You can either drag & upload this file into your Looker project, or create a manifest.lkml with the same content. Change the id, label, or url as needed.

   application: my-basic-extension {
     label: "My Basic Extension"
     url: "http://localhost:8080/bundle.js"
   }
   

7. Create a model LookML file in your project. The name doesn't matter. The model and connection won't be used, and in the future this step may be eliminated.

   • Add a connection in this model. It can be any connection, it doesn't matter which.
   • Configure the model you created so that it has access to some connection.

8. Connect your new project to Git. You can do this multiple ways:

   • Create a new repository on GitHub or a similar service, and follow the instructions to connect your project to Git
   • A simpler but less powerful approach is to set up git with the "Bare" repository option which does not require connecting to an external Git Service.

9. Commit your changes and deploy your them to production through the Project UI.

10. Reload the page and click the Browse dropdown menu. You should see your extension in the list.

    • The extension will load the JavaScript from the url you provided in the application definition/
    • Reloading the extension page will bring in any new code changes from the extension template. (Webpack's hot reloading is not currently supported.)

Deployment

The process above requires your local development server to be running to load the extension code. To allow other people to use the extension, we can build the JavaScript file and include it in the project directly.

1. In your extension project directory on your development machine you can build the extension with yarn build.
2. Drag and drop the generated dist/bundle.js file into the Looker project interface
3. Modify your manifest.lkml to use file instead of url:

   application: my-basic-extension {
     label: "My Basic Extension"
     file: "bundle.js"
   }