Shopify Functions Rust Crate

A crate to help developers build Shopify Functions.

Dependencies

• Make sure you have graphql_client in your dependencies

  cargo add graphql_client@0.14.0
  

Usage

• The generate_types macro allows you to generate structs based on your input query. It will also generate output/response types for the current Function API, based on the provided schema.
• The shopify_function attribute macro marks the following function as the entry point for a Shopify Function. It manages the Functions STDIN input parsing and STDOUT output serialization for you.
• The run_function_with_input function is a utility for unit testing which allows you to quickly add new tests based on a given JSON input string.

See the example for details on usage, or use the following guide to convert an existing Rust-based function.

Updating an existing function to use shopify_function

1. cargo add shopify_function

2. cargo add graphql_client@0.14.0

3. Delete src/api.rs.

4. In main.rs:

   1. Add imports for shopify_function.

      use shopify_function::prelude::*;
      use shopify_function::Result;
      

   2. Remove references to mod api.

   3. Add type generation, right under your imports.

      generate_types!(query_path = "./input.graphql", schema_path = "./schema.graphql");
      

   4. Remove the main function entirely.

   5. Attribute the function function with the shopify_function macro, and change its return type.

      #[shopify_function]
      fn function(input: input::ResponseData) -> Result<output::FunctionResult> {
      

   6. Update the types and fields utilized in the function to the new, auto-generated structs. For example:

      Old	New
      input::Input	input::ResponseData
      input::Metafield	input::InputDiscountNodeMetafield
      input::DiscountNode	input::InputDiscountNode
      FunctionResult	output::FunctionResult
      DiscountApplicationStrategy::First	output::DiscountApplicationStrategy::FIRST

5. Add .output.graphql to your .gitignore.

Viewing the generated types

To preview the types generated by the generate_types macro, use the cargo doc command.

cargo doc --open

You can also use the cargo-expand crate to view the generated source, or use the rust-analyzer VSCode extension to get IntelliSense for Rust and the generated types.

License Apache-2.0