Crate dataflow_rs 

A high-performance rules engine for IFTTT-style automation and data processing pipelines in Rust.

Workflows are JSON definitions whose tasks run built-in or host functions over a Message’s context, with JSONLogic conditions and expressions compiled once at build time.

• def: parse and lint authored workflow JSON into a WorkflowDef.
• program: compile definitions against a Registry into an immutable program::Program.
• run: execute a program over a Message with Engine::run or Engine::run_with, returning a Run on every outcome.
• function: implement Function with a #[derive(FunctionConfig)] config for typed async host actions, or wrap calls in a function::CallLayer.
• expr: compiled Expr<T>, Path, expr::Output, expr::Interpolated documents, and expr::Secrets.
• observe: inline Observer events and replayable observe::Traces.
• compat: migrate 3.x definitions to the 4.0 spelling with compat::migrate_v3.

Features

None is on by default. The six standard extension operator families (ExtString, ExtArray, ExtMath, ExtControl, ExtObject and ErrorHandling) are compiled in unconditionally and selected at runtime on expr::ExprEngineBuilder, which defaults to expr::OperatorFamily::Core (and secret) only.

• datetime: compiles in the expr::OperatorFamily::Datetime operators (still selected at runtime on expr::ExprEngineBuilder) and changes == and the ordering operators on plain date-shaped strings across the build.
• tensor: the Tensor value and expr::OperatorFamily::Tensor operators (selected at runtime on expr::ExprEngineBuilder). Not in expr::ExprEngineBuilder::all_operators, since names like shape, full, cast and concat are ordinary JSON keys.
• budget: a ceiling on the operations of one evaluation, which ExprEngineBuilder::ops_budget sets.
• wasm-web: the browser’s clock and randomness, which wasm32-unknown-unknown needs and native targets must not pull in.
• ts: derives ts_rs::TS on the wire shapes, from which tests/ts_types.rs renders bindings/dataflow.d.ts, which ships in the package. ts is outside semver: the wire shapes are covered by semver, but the generator, its output’s layout and this feature’s dependencies may change in any release.

Dependencies in the API

datalogic_rs and datavalue are re-exported, and part of this crate’s API: a value is a datavalue::OwnedDataValue (a context, a secret, a resolved config), and a host’s custom operator is a datalogic_rs::CustomOperator. A host names both through these re-exports, so its versions are always the engine’s. A major version of either is a major version of this crate.

Re-exports

pub use crate::def::WorkflowDef;

pub use crate::expr::Expr;

pub use crate::expr::Path;

pub use crate::function::Ctx;

pub use crate::function::Function;

pub use crate::function::Outcome;

pub use crate::function::Registry;

pub use crate::observe::Observer;

pub use crate::run::Engine;

pub use crate::run::Message;

pub use crate::run::Run;

pub use crate::run::RunOptions;

pub use datalogic_rs;

pub use datavalue;

Modules

compat

Compatibility with v3 definitions and behaviour.

def

Definitions: the authored form of workflows and tasks.

expr

Expressions: the JSONLogic surface a definition is written in.

function

Functions: the typed units of work a task runs.

observe

What a run reports about itself: as it goes, to an Observer, and once it ends, on its Run, with its Trace when one was asked for.

program

Programs: a definition compiled for execution.

run

Runs: executing a program over a message.

Structs

Error

Why a run, a compile or a function failed.

Issue

One finding about an authored definition.

Enums

ErrorKind

The class of an Error. It decides the recorded code.

Constants

VERSION

The crate version.

Type Aliases

Result

The result of a fallible v4 operation.