codegen

Codegen

This crate contains the code necessary to generate the generated portion of the client code.

main.rs contains the code for this. At a high-level, the process to generate the Rust SDK client functions has 3 steps:

• Parse the protos and produce a set of Rust files from them with tonic_build (which uses prost under the hood).
• Manually parse the grpc annotations from the top-level service definition. These annotations are crucial because they define REST methods, URLs, etc.
• For each parsed endpoint, produce a generated client method with the right input and output types. This is easy for queries, but tricky for Turnkey activities because the mapping of URL to inner intent and result type isn't defined structurally. Hence the need to bring in activities.json, a mapping which defines exactly this.
• Finally, cleanup our generated code with a final transform step which parses the generated Rust code and applies a few transformations to it
  • replaces i32 enum types with proper types (e.g. pub effect: i32 -> pub effect: super::super::super::immutable::common::v1::Effect,)
  • transform enums: remove #[derive(...)] prost traits, remove #[prost(...)] attributes, remove #[repr(i32)], and add #[serde(rename = "ENUM_NAME_VARIANT")] (necesary for JSON serialization and deserialization to work correctly)
  • transform structs: remove #[prost(...)] attributes, add #[serde(default)] to help with deserialization of empty lists or optional params, add #[serde(flatten)] to ignore the Inner struct which is a result of the oneof structure of activity intent and results. The serialized JSON doesn't have "inner".