Runs

Runs

A run is a single execution of a workflow definition – it tracks the live state of every step from creation to terminal status.

WorkflowRun

When you start a workflow, the engine creates a WorkflowRun with all steps initialized to pending. The run holds mutable state that evolves as events arrive.

Key fields:

Field	Type	Purpose
`RunID`	`string`	Unique execution identifier
`WorkflowID`	`string`	Name of the workflow definition
`Status`	`RunStatus`	Current lifecycle state
`Steps`	`map[string]StepState`	Per-step mutable state
`Input`	`json.RawMessage`	Original user-supplied payload
`CreatedAt`	`time.Time`	When the run was created (UTC)
`ParentRunID`	`string`	Set for child sub-workflow runs
`Deadline`	`*time.Time`	Workflow-level timeout deadline

Run Status State Machine

A run progresses through these states:

    stateDiagram-v2
    [*] --> Pending
    Pending --> Running: engine claims run
    Running --> Completed: all steps succeed
    Running --> Failed: step fails permanently
    Running --> Cancelled: external cancellation
    Running --> Compensated: saga rollback succeeds
    Running --> CompensateFailed: saga rollback fails
    Completed --> [*]
    Failed --> [*]
    Cancelled --> [*]
    Compensated --> [*]
    CompensateFailed --> [*]

Status	Meaning
`pending`	Created but not yet claimed by the engine
`running`	Engine is actively scheduling steps
`completed`	All non-auxiliary steps finished successfully
`failed`	A step failed permanently (retries exhausted, no compensation)
`cancelled`	Cancelled via API, CLI, or `CancelOn` event
`compensated`	Failed but saga compensation succeeded
`compensate_failed`	Compensation itself failed

All statuses except pending and running are terminal – once reached, the run never changes state again.

Step Status States

Each step within a run has its own status:

Status	Meaning
`pending`	Not yet ready (dependencies unsatisfied)
`queued`	Dispatched to NATS, waiting for a worker
`running`	Worker is executing the task
`completed`	Finished successfully with output
`failed`	Failed permanently
`skipped`	Bypassed via `SkipIf` condition
`cancelled`	Run was cancelled while step was in progress
`recovered`	Failed but recovered via OnFailure handler

Input and Output

Run input is an arbitrary JSON payload supplied when starting the workflow. It is preserved on the WorkflowRun so retries can reuse it. Steps with no dependencies receive the run input as their task input.

Step output is stored as raw bytes on StepState.Output. Downstream steps receive the output of their dependencies as input. For steps with multiple dependencies, the engine assembles a merged input payload.

Starting a Run

Via CLI:

dagnats run start my-workflow '{"key": "value"}'

Via API:

runID, err := svc.StartRun(ctx, "my-workflow", inputJSON)

Inspecting a Run

dagnats run get <run-id>
dagnats run list --workflow=my-workflow --status=running

The get command shows the run status, each step’s status, and timing information. The list command filters runs by workflow name, status, and time range.

Cancelling a Run

dagnats run cancel <run-id>

Cancellation transitions the run to cancelled and terminates any in-flight steps. Steps that have already completed retain their output. Steps that are pending or queued are moved to cancelled without execution.

Workflows can also self-cancel via the CancelOn builder option, which watches for a matching external event.

Workflows and DAGs – defining what a run executes
Events and Event Sourcing – how run state changes are recorded
Workers – what executes the steps in a run

Workers Events and Event Sourcing