Enum EngineError 

pub enum EngineError {
    Operation(OperationError),
    Store(StoreError),
    InvalidWorkflow(String),
    StepConfig(String),
    Decision(DecisionError),
    NoDecisionProvider {
        step: String,
    },
    Serialization(Error),
    RunBudgetExceeded {
        run_id: Uuid,
        limit_usd: Decimal,
        spent_usd: Decimal,
        step_budget_usd: Decimal,
    },
    MonthlyBudgetExceeded {
        limit_usd: Decimal,
        spent_usd: Decimal,
    },
    MissingArtifact {
        step: String,
        pattern: String,
    },
    ArtifactNotDeclared {
        step: String,
        name: String,
    },
    ArtifactNotFound {
        step: String,
        name: String,
    },
    ArtifactsUnavailable(String),
    Artifact(ArtifactError),
    ApprovalRequired {
        run_id: Uuid,
        step_id: Uuid,
        message: String,
    },
    ApprovalRejected {
        run_id: Uuid,
        step_id: Uuid,
        reason: String,
    },
    HumanInputRequired {
        run_id: Uuid,
        step_id: Uuid,
        message: String,
    },
    HumanInputRejected {
        run_id: Uuid,
        step_id: Uuid,
        reason: String,
    },
    DelaySleeping {
        run_id: Uuid,
        step_id: Uuid,
        wake_at: DateTime<Utc>,
    },
    WorkflowGuardRejected(WorkflowRejection),
    ReplayDivergence {
        position: u32,
        expected: String,
        recorded: String,
    },
    HandlerVersionMismatch {
        run_id: Uuid,
        workflow_name: String,
        run_version: String,
        current_version: String,
    },
}

Errors produced by the workflow engine.

Variants

Operation(OperationError)

An operation (Shell, Http, Agent) failed during step execution.

Store(StoreError)

The backing store returned an error.

InvalidWorkflow(String)

The workflow definition is invalid.

StepConfig(String)

A step configuration could not be deserialized for execution.

Decision(DecisionError)

A decision answer was accessed by name with the wrong type or a missing key.

NoDecisionProvider

A decision step was reached but no DecisionProvider is wired into the engine.

Fields

step: String

The decision step that could not run.

Serialization(Error)

JSON serialization error.

RunBudgetExceeded

The run reached its cumulative cost cap before launching an agent step.

Raised before the step is created, so no work and no spend happen. The engine transitions the run to Cancelled.

Fields

run_id: Uuid

The run that hit its cap.

limit_usd: Decimal

The configured cap, in USD.

spent_usd: Decimal

Cost already accumulated by this run and its ancestors, in USD.

step_budget_usd: Decimal

Declared budget of the step that was about to run, in USD.

MonthlyBudgetExceeded

The global monthly cost quota is exhausted; no new run may be created.

Runs already in flight are never interrupted by this error.

Fields

limit_usd: Decimal

The configured monthly quota, in USD.

spent_usd: Decimal

Cost already spent during the current calendar month, in USD.

MissingArtifact

A step declared an output that produced no file.

Raised only when the step itself succeeded: a declared output that never materialised is a broken contract, and failing here beats failing later in whichever step tried to consume it.

Fields

step: String

Name of the step that declared the output.

pattern: String

The unmatched pattern.

ArtifactNotDeclared

A handle was asked for an artifact the step never declared.

Fields

step: String

Name of the step the handle was asked from.

name: String

Name of the artifact that was asked for.

ArtifactNotFound

A step asked for an artifact that no earlier step produced.

Fields

step: String

Name of the producing step that was searched for.

name: String

Name of the artifact that was searched for.

ArtifactsUnavailable(String)

Artifacts were used but no storage backend is configured.

Artifact(ArtifactError)

The artifact storage backend failed.

ApprovalRequired

The run requires human approval before continuing.

Fields

run_id: Uuid

The run that is awaiting approval.

step_id: Uuid

The approval step that triggered the pause.

message: String

The approval message.

ApprovalRejected

An approval gate was rejected instead of granted.

Raised when a StepInterceptor resolves the gate with ApprovalOutcome::Rejected. The engine fails the run; the rejection is deterministic, so the run is never replayed.

Fields

run_id: Uuid

The run that was stopped.

step_id: Uuid

The approval step that was rejected.

reason: String

Why the gate was refused.

HumanInputRequired

The run waits for a typed human input before continuing.

Raised by WorkflowContext::human_input when no answer has been given yet. The engine transitions the run to AwaitingApproval.

Fields

run_id: Uuid

The run that is awaiting input.

step_id: Uuid

The human input step that triggered the pause.

message: String

The message displayed to the person answering.

HumanInputRejected

A human input request was rejected instead of answered.

Returned to the handler by WorkflowContext::human_input, which decides what happens next. A propagated rejection fails the run, and the run is never retried.

Fields

run_id: Uuid

The run the input belongs to.

step_id: Uuid

The human input step that was rejected.

reason: String

Why the input was refused.

DelaySleeping

A delay step suspended the run until the given time.

The engine transitions the run to Sleeping and sets scheduled_at so the worker re-queues it automatically.

Fields

run_id: Uuid

The run that is sleeping.

step_id: Uuid

The delay step.

wake_at: DateTime<Utc>

When the run should be woken up.

WorkflowGuardRejected(WorkflowRejection)

A workflow invocation was rejected by the workflow guard.

The run is transitioned to Cancelled when this error is raised.

ReplayDivergence

The step stored at position does not match the step the handler just called: its name or its StepKind differ from what was recorded before the run was suspended.

Raised instead of silently serving another step’s cached output when the handler’s code changed while the run was suspended (a deploy during a pending approval, human input, decision escalation or delay): step positions can shift, and without this check every step after the divergence point would silently receive another step’s output, vote or approval.

Fields

position: u32

The step position where the recorded step and the step just called stopped matching.

expected: String

Identity (name (kind)) of the step the handler just called.

recorded: String

Identity (name (kind)) of the step recorded at position.

HandlerVersionMismatch

The run’s handler changed since the run was created or suspended, and the handler’s current version is not declared compatible with the version the run was created with.

Checked before any step is replayed, on the same rule the manual retry endpoint applies (HANDLER_VERSION_MISMATCH). Unlike retry, resume has no force override: replaying an incompatible handler’s steps risks serving one step’s cached output to another (see ReplayDivergence).

Fields

run_id: Uuid

The run that cannot be resumed.

workflow_name: String

The handler’s registered name.

run_version: String

The handler version the run was created with.

current_version: String

The handler’s current version.

Trait Implementations

impl Debug for EngineError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for EngineError

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for EngineError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<ArtifactError> for EngineError

fn from(source: ArtifactError) -> Self

Converts to this type from the input type.

impl From<DecisionError> for EngineError

fn from(source: DecisionError) -> Self

Converts to this type from the input type.

impl From<Error> for EngineError

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<OperationError> for EngineError

fn from(source: OperationError) -> Self

Converts to this type from the input type.

impl From<StoreError> for EngineError

fn from(source: StoreError) -> Self

Converts to this type from the input type.

impl From<WorkflowRejection> for EngineError

fn from(source: WorkflowRejection) -> Self

Converts to this type from the input type.