Getting started with building location rules

In this tutorial, you’ll learn how to do the following tasks:

• Generate starter code for Shopify Functions.
• Use GraphQL to define the input of your function.
• Deploy functions to the Shopify platform.
• Use the order routing settings to create a location rule in a Shopify store.
• Review logs for your function.

• You've created a Partner account.
• You've created a development store.

• You've created an app that uses Shopify CLI 3.0 or higher. If you previously installed Shopify CLI, then make sure you're using the latest version.

  If you plan to create a UI for your extension, then start with the Remix app template.

• You've installed Node.js 16 or higher.

• You've installed your app on the development store.

The following requirements are specific to Rust-based development with Shopify Functions.

• You've installed Rust.

  On Windows, Rust requires the Microsoft C++ Build Tools. Make sure to select the Desktop development with C++ workload when installing the tools.

• You've installed cargo-wasi:

To create your location rule function, you can use Shopify CLI to generate a starter function, specify the inputs for your function using an input query, and implement your function logic using Rust.

1. Navigate to your app directory:

2. Run one of the following commands to create a new location rule extension:

3. Choose the language that you want to use. For this tutorial, you should select either JavaScript or Rust.

4. Navigate to extensions/location-rule:

5. Replace the contents of input.graphql file with the following code:

   input.graphql defines the input for the function. You need the fulfillment groups, with the available locations for the items in the group.

6. If you're using JavaScript, then run the following command to regenerate types based on your input query:

7. Replace the src/index.js or src/main.rs file with the following code.

   The function logic sorts the locations by a given metafield.

8. If you're using Rust, then build the function's Wasm module:

   If you encounter any errors, then ensure that you've installed Rust and cargo-wasi.

To test your function, you need to make it available to your development store.

1. If you're developing a function in a language other than JavaScript, TypeScript, or Rust, ensure you have configured build.watch in your function settings.

2. Navigate back to your app root:

3. Use the Shopify CLI dev command to start app preview:

   You can keep the this preview running as you work on your function. When you make changes to a watched file, Shopify CLI rebuilds your function and updates the function extension's drafts, so you can immediately test your changes.

4. Follow the CLI prompts to preview your app, and install it on your development store.

You can test your location rule to ensure it's working as expected, and review logs for your function.

1. From the Shopify admin, go to Settings > Shipping and delivery.

2. Click manage in the Order routing section.

   Make sure you have at least two locations in your store, and that one of them is in Canada.

3. Click Add rule.

   Your new rule should be an available option.

4. Add your new rule and drag it to the top to make it your highest priority location rule.

5. Open your development store, build a cart, and proceed through checkout.

6. Open your development store's admin, and find your new order. This should be assigned to your Canadian location.

7. To debug your function, or view its output, you can review its logs in your Partner Dashboard.

   1. Log in to your Partner Dashboard and navigate to Apps > {your app} > Extensions > order-routing-location-rule.
   2. Click on any function run to view its input, output, and any logs written to STDERR.

• Learn more about how Shopify Functions work and the benefits of using Shopify Functions.
• Consult the API references for Shopify Functions.
• Learn how to use variables in your input query.