Eva

Rust building blocks: data types, service interfaces, handlers, and application startup.

[dependencies]
eva = { git = "https://github.com/nerodono/eva" }

use eva::{endpoint, service};

#[service]
pub trait Greetings {
    fn greet(name: String) -> Struct! { message: String };
}

#[endpoint(Greetings::greet)]
pub async fn Greet(_: (), args: this::Args) -> this::Output {
    Ok(this::Ok { message: format!("Hello, {}!", args.name) })
}

Use eva for the umbrella API, or depend on individual crates:

Crate	Provides
eva-core	Time, collections, hashing, utilities, and data reexports.
eva-data	#[data], #[int], #[str], their types, serialization, and schemas.
eva-handlers	Endpoints, middleware, and service macros.
eva-rt	Runtime, Components, configuration, and executor setup.

eva includes core and handlers by default. Enable rt for eva::rt, cli for Runtime with command-line parsing, and logforth for logging. Use figment for JSON/TOML and env configuration, yaml for YAML, and otel for OpenTelemetry logging.

eva-data/rand adds random sampling for #[int] enums. eva-core enables it automatically.

Standalone eva-handlers has no dependencies by default; enable macros for #[service], #[endpoint], #[export], and #[implement]. Endpoints add tracing automatically; not(trace) opts out, and enable-tracing enables span collection.

API docs: cargo doc --open.

Nix

eva.lib.mkServiceFlake provides a pinned Rust toolchain, a crane build, a dev shell, and a NixOS service module:

{
  inputs.eva.url = "github:nerodono/eva";

  outputs = { self, eva, ... }: eva.lib.mkServiceFlake {
    inherit self;
    pname = "my-service";
    mainProgram = "my-service-server"; # defaults to pname
    description = "My service";
    settingsDefaults = { http.listen = "127.0.0.1:8080"; };
    secretFields = [ "db.password" ];
  };
}

Import nixosModules.default and configure services.my-service: enable, settings, extraConfigFiles, user, group, and environment. secrets."db.password" accepts a secret file path delivered through systemd credentials. Config files use TOML by default; format = "yaml" requires the Rust yaml feature.

Customize builds with env, srcFilter, and devShell; customize the unit with extraServiceConfig. The individual helpers are also available in eva.lib.