Function execute_run

crates/buzz-workflow/src/executor.rs:981–1015

Execute a workflow run sequentially. Steps run in order. Each step: 1. Evaluates `if:` condition (skip if false). 2. Resolves template variables in action fields. 3. Dispatches the action. 4. Stores the step output for use by later steps. On `RequestApproval`: returns `ExecutionResult` with `approval_token = Some(token)`. Caller must persist the approval record and update the run status. Return

(
    engine: &WorkflowEngine,
    community_id: CommunityId,
    run_id: Uuid,
    def: &WorkflowDef,
    trigger_ctx: &TriggerContext,
)

/// [`WorkflowError::CapacityExceeded`] immediately if all permits are taken.
/// Transitions the run to `Running` after acquiring a permit.
pub async fn execute_run(
    engine: &WorkflowEngine,
    community_id: CommunityId,
    run_id: Uuid,
    def: &WorkflowDef,
    trigger_ctx: &TriggerContext,
) -> Result<ExecutionResult, (WorkflowError, crate::error::PartialProgress)> {
    // Fail fast if all concurrency permits are in use — no queuing.
    let _permit = engine.run_semaphore.try_acquire().map_err(|_| {
        (
            WorkflowError::CapacityExceeded,
            crate::error::PartialProgress::default(),
        )
    })?;

    engine
        .db
        .update_workflow_run(
            community_id,
            run_id,
            buzz_db::workflow::RunStatus::Running,
            0,
            &serde_json::json!([]),
            None,
        )
        .await
        .map_err(|e| {
            (
                WorkflowError::from(e),
                crate::error::PartialProgress::default(),
            )
        })?;

    execute_steps(engine, community_id, run_id, def, trigger_ctx, 0, None).await
}

/// Resume execution from a specific step index (used for approval resume).
///