Looker Extension Template (React & TypeScript)

This repository demonstrates functions that are available to the Extension SDK. It can be used as

It uses React and TypeScript for writing your extension, the React Extension SDK for interacting with Looker, and Webpack for building your code.

Getting Started for Development

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

2. Navigate (cd) to the template 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.

   The default yarn start command runs with hot module replacement working. Some changes will cause a full reload of the extension iframe. When this happens the extension framework connection will break. You should see an error. You will need to do a full page reload of the outer page.

   To run without hot module replacement run yarn start-no-hot

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-great-extension {
     label: "My Great 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-great-extension {
     label: "My Great Extension"
     file: "bundle.js"
   }
   

Notes

• Webpack's hot reloading is not currently supported.
• Webpack's module splitting is not currently supported.
• The template uses Looker's component library and styled components. Neither of these libraries are required so you may remove and replace them with a component library of your own choice,

Related Projects

• Looker React extension template
• Looker React/Redux extension template
• Looker extension SDK
• Looker extension SDK for React
• Looker SDK
• Looker Components
• Styled components