Vovk.ts Rust client

vovk-rust generates typed Rust crate from same .vovk-schema/ artifacts driving TS client. Async by default via reqwest + tokio; streaming via futures.

Experimental — generated API may shift between Vovk versions. Pin crate version on consume.

Scope

Covers:

• Install vovk-rust + generate Rust crate.
• Templates: rs (standalone crate) vs rsSrc (source files to embed).
• Auto-gen config in vovk.config.mjs.
• Async call shape + nested-module _:: type convention.
• JSON Lines streaming via futures::Stream.
• Client-side validation toggle.
• crates.io publishing flow.

Out of scope:

• Procedure / controller authoring → procedure skill.
• vovk bundle general (TS, Python) → bundle skill.
• Server-side JSON Lines → jsonlines skill.

Install + generate

npm i -D vovk-rust

Standalone crate

Canonical output dir ./dist_rust (hello-world convention):

npx vovk generate --from rs --out ./dist_rust

Output:

dist_rust/
  src/http_request.rs       # HTTP handling
  src/lib.rs                # RPC functions + types
  src/read_full_schema.rs   # Schema utilities
  src/schema.json           # Vovk schema (read at runtime via CARGO_MANIFEST_DIR/src/schema.json)
  Cargo.toml                # edition = "2021"
  README.md

Embedded source

npx vovk generate --from rsSrc --out ./rust_src

Auto-generate with composed client

// vovk.config.mjs
const config = {
  composedClient: {
    fromTemplates: ['js', 'rs'],
  },
};
export default config;

Bake prod API URL via clientTemplateDefs.rs.outputConfig.origin — generated crate uses this by default. Pattern from hello-world:

// vovk.config.js
const PROD_ORIGIN = 'https://hello-world.vovk.dev';

const config = {
  composedClient: { fromTemplates: ['js', 'rs'] },
  clientTemplateDefs: {
    rs: {
      extends: 'rs',
      outputConfig: { origin: PROD_ORIGIN },
      // composedClient: { outDir: './my_other_dir' }, // optional — defaults to ./dist_rust
    },
  },
};

Consumers can still override per call via api_root arg.

Generated call shape

Every RPC function async, takes positional args: body, query, params, headers?, api_root?, disable_client_validation.

pub async fn update_user(
    body: update_user_::body,
    query: update_user_::query,
    params: update_user_::params,
    headers: Option<&HashMap<String, String>>,
    api_root: Option<&str>,
    disable_client_validation: bool,
) -> Result<update_user_::output, HttpException>

Per-endpoint type variation (verified in packages/vovk-rust/client-templates/rsSrc/lib.rs.ejs:60-67): each of query, params typed <handler_name>_::query / _::params only when procedure declares validation for that key; else slot is Rust unit type () → pass () at call site. body has three cases: multipart/form-data content-type → reqwest::multipart::Form; declared body validation (JSON / text / binary) → <handler>_::body; no body → (). So endpoint with no body/query/params signature:

pub async fn ping(
    body: (), query: (), params: (),
    headers: Option<&HashMap<String, String>>,
    api_root: Option<&str>,
    disable_client_validation: bool,
) -> Result<serde_json::Value, HttpException>

Method names lodash snakeCase(handlerName) — getUser → get_user, findPetsByStatus → find_pets_by_status, UserRPC (module) → user_rpc.

Nested types use _:: module syntax. body.profile typed update_user_::body_::profile. How generator flattens deep JSON Schema into Rust modules.

Usage

use my_api_client::user_rpc;

pub async fn run() -> Result<(), Box<dyn std::error::Error>> {
    use user_rpc::update_user_::{
        body as Body,
        body_::profile as Profile,
        query as Query,
        query_::notify as Notify,
        params as Params,
    };

    let response = user_rpc::update_user(
        Body {
            email: String::from("john@example.com"),
            profile: Profile {
                name: String::from("John Doe"),
                age: 25,
            },
        },
        Query { notify: Notify::email },
        Params {
            id: String::from("123e4567-e89b-12d3-a456-426614174000"),
        },
        None,   // headers
        None,   // api_root — overrides baked-in URL
        false,  // disable_client_validation
    )
    .await?;

    Ok(())
}

Method names Rust-side snake_case; user_rpc module reflects UserRPC controller. Module path (my_api_client above) depends on crate name set at generation time.

JSON Lines streaming

Streaming endpoints return pinned boxed Stream:

pub async fn stream_tokens(
    body: (), query: (), params: (),
    headers: Option<&HashMap<String, String>>,
    api_root: Option<&str>,
    disable_client_validation: bool,
) -> Result<
    Pin<Box<dyn Stream<Item = Result<stream_tokens_::iteration, HttpException>> + Send>>,
    HttpException,
>

Consume with futures::StreamExt:

use futures::StreamExt;
use my_api_client::stream_rpc;

pub async fn consume_stream() -> Result<(), Box<dyn std::error::Error>> {
    let mut stream = stream_rpc::stream_tokens((), (), (), None, None, false).await?;
    while let Some(item) = stream.next().await {
        let val = item.expect("stream item should be Ok");
        println!("{}", val.message);
    }
    Ok(())
}

See jsonlines skill for server side.

Dependencies pulled in

Generated Cargo.toml brings (per hello-world):

[dependencies]
serde_json    = "1.0"
futures-util  = "0.3"
jsonschema    = "0.17"
urlencoding   = "2.1"
once_cell     = "1.17"

[dependencies.serde]
version  = "1.0"
features = ["derive"]

[dependencies.reqwest]
version  = "0.12"
features = ["json", "multipart", "stream"]

[dependencies.tokio]
version  = "1"
features = ["macros", "rt-multi-thread", "io-util"]

[dependencies.tokio-util]
version  = "0.7"
features = ["codec"]

• reqwest 0.12 — async HTTP, with multipart and stream features for file uploads + JSON Lines.
• tokio 1 — async runtime. Generated crate assumes multi-thread runtime available; consumers pull transitively but typically add directly with #[tokio::main] for binaries.
• tokio-util (codec) — line-delimited framing for JSON Lines decoding.
• serde (derive) + serde_json — (de)serialization.
• futures-util — streaming combinators (StreamExt::next etc).
• jsonschema 0.17 — client-side validation against schema.json.
• urlencoding + once_cell — internal utilities.

Auth + base URL

Pass api_root per call to override baked-in URL. Pass &HashMap<String, String> of headers for auth (Bearer token, API key, whatever upstream needs):

let mut headers = HashMap::new();
headers.insert("Authorization".into(), format!("Bearer {token}"));

let resp = user_rpc::get_user(
    (), (), Params { id },
    Some(&headers),
    Some("https://api.example.com"),
    false,
).await?;

Don't bake secrets into crate. Consumers supply auth at call time.

Client-side validation

Runs by default. Last positional arg disables:

user_rpc::update_user(body, query, params, None, None, true /* disable */).await?;

Skip for hot paths; keep on for safety in app code.

Publishing to crates.io

Canonical script from hello-world — note --allow-dirty, needed since generated crate is uncommitted build artifact:

cargo publish --manifest-path dist_rust/Cargo.toml --allow-dirty

Wire into release flow alongside npm bundle + Python package (hello-world chains all three under postversion):

"scripts": {
  "publish:node":   "npm publish ./dist",
  "publish:rust":   "cargo publish --manifest-path dist_rust/Cargo.toml --allow-dirty",
  "publish:python": "python3 -m build ./dist_python --wheel --sdist && python3 -m twine upload ./dist_python/dist/*",
  "postversion":    "vovk generate && vovk bundle && npm run publish:node && npm run publish:rust && npm run publish:python"
}

Crate name / version flow from root package.json (generator copies fields into generated Cargo.toml). Hello-world example crate vovk_hello_world (underscored, since hyphens crates.io-discouraged).

Flows

"Call my Vovk API from a Rust service"

1. npm i -D vovk-rust.
2. Add 'rs' to composedClient.fromTemplates.
3. npx vovk generate.
4. Add generated crate as path dependency in consumer's Cargo.toml.
5. use my_api::user_rpc; and call.

"Ship a Rust SDK to crates.io"

1. npx vovk generate --from rs --out ./rust_package.
2. Set info.title + info.version in vovk.config.mjs first.
3. cargo publish --manifest-path rust_package/Cargo.toml.

"Consume a streaming endpoint from Rust"

use futures::StreamExt;
let mut stream = chat_rpc::stream_tokens(body, (), (), None, None, false).await?;
while let Some(chunk) = stream.next().await {
    print!("{}", chunk?.message);
}

"Embed the client into an existing Rust crate"

Use rsSrc:

npx vovk generate --from rsSrc --out ./src/api

Add module to src/lib.rs: pub mod api;.

Gotchas

• Experimental. Pin crate version; expect breaks on Vovk upgrades. Integration-test after each bump.
• Nested types deep. body_::profile_::address_::zip patterns common. use ... as Name; import trick keeps call sites readable.
• OpenAPI mixins with circular $refs not fully supported yet — if mixin has cycles, generator may fail. Roadmap.
• text/plain and application/octet-stream body params not fully supported — JSON is solid path today.
• Named schemas in components/schemas don't yet produce importable shared types — roadmap. Every call site gets own scoped types.
• Streaming needs futures::StreamExt — forget import → .next() won't compile.
• Regen on schema changes. CI should regen as part of build, same as TS/Python.
• Don't hand-edit generated files. Put shared utilities alongside, not inside, generated crate.