szal 1.0.1

Workflow engine — step/flow execution with branching, retry, rollback, and parallel stages
Documentation

Szál

Szál (Hungarian: thread) — Workflow orchestration engine for Rust

Crates.io CI License: AGPL-3.0

Define steps, wire them into flows with branching, retry, and rollback — then execute sequentially, in parallel, or as a DAG. Part of the AGNOS ecosystem.

Quick start

[dependencies]
szal = "0.26"

Sequential flow

use szal::flow::{FlowDef, FlowMode};
use szal::step::StepDef;

let mut flow = FlowDef::new("deploy-pipeline", FlowMode::Sequential);
flow.add_step(StepDef::new("build").with_timeout(60_000));
flow.add_step(StepDef::new("test").with_retries(2, 1_000));
flow.add_step(StepDef::new("deploy").with_rollback());
flow.validate().unwrap();

DAG workflow

use szal::flow::{FlowDef, FlowMode};
use szal::step::StepDef;

let build = StepDef::new("build");
let unit_test = StepDef::new("unit-test").depends_on(build.id);
let integ_test = StepDef::new("integ-test").depends_on(build.id);
let deploy = StepDef::new("deploy")
    .depends_on(unit_test.id)
    .depends_on(integ_test.id);

let mut flow = FlowDef::new("ci-cd", FlowMode::Dag);
flow.add_step(build);
flow.add_step(unit_test);
flow.add_step(integ_test);
flow.add_step(deploy);
flow.validate().unwrap(); // cycle detection + dependency validation

State machine

use szal::state::WorkflowState;

let state = WorkflowState::Created;
assert!(state.valid_transition(&WorkflowState::Running));
assert!(!state.is_terminal());

Modules

Module Description
step Atomic workflow steps — timeout, retry, rollback, DAG dependencies
flow Flow composition — sequential, parallel, DAG (Kahn's), hierarchical
engine Execution config and flow result aggregation
state Workflow state machine with validated transitions
error Typed errors — step failure, timeout, retry exhaustion, cycle detection

Execution modes

Mode Description
Sequential Steps run one after another
Parallel Steps run concurrently (no dependencies)
Dag Dependency graph with cycle detection (DFS)
Hierarchical Manager step delegates to sub-steps

Roadmap to v1.0

Version Milestone Status
0.22 MCP protocol layer, majra integration, ai-hwaccel, examples, fuzz targets Done
0.23 Agent orchestration + LLM gateway (~200 tools) Done
0.24 Security/governance + integration tools (~350 tools) Done
0.25 Knowledge, training, simulation tools (~490 tools) Done
0.26 Consolidation, hardening, supply chain security Current
1.0 Stable unified MCP engine —

License

AGPL-3.0-only