Error Handling

Shield defines sentinel errors in the root shield package. All errors are created with errors.New and can be checked with errors.Is.

Store errors01

Error	Description
`ErrNoStore`	No store was configured on the engine
`ErrStoreClosed`	The store has been closed
`ErrMigrateFailed`	Database migration failed

Error	Description
`ErrScanNotFound`	Scan result with the given ID does not exist
`ErrPolicyNotFound`	Policy with the given ID does not exist
`ErrInstinctNotFound`	Instinct with the given ID does not exist
`ErrJudgmentNotFound`	Judgment with the given ID does not exist
`ErrAwarenessNotFound`	Awareness detector with the given ID does not exist
`ErrValueNotFound`	Value with the given ID does not exist
`ErrReflexNotFound`	Reflex with the given ID does not exist
`ErrBoundaryNotFound`	Boundary with the given ID does not exist
`ErrProfileNotFound`	Safety profile with the given ID does not exist
`ErrPIITokenNotFound`	PII token with the given ID does not exist
`ErrComplianceNotFound`	Compliance report with the given ID does not exist

Error	Description
`ErrAlreadyExists`	A resource with the same name already exists

Error	Description
`ErrInputBlocked`	Input content was blocked by safety scan
`ErrOutputBlocked`	Output content was blocked by safety scan

Error	Description
`ErrNoProfile`	No safety profile configured for the scan
`ErrInvalidConfig`	Invalid engine configuration

Error	Description
`ErrEncryptionKeyMissing`	PII encryption key not configured

Error	Description
`ErrInvalidState`	Invalid state transition

Store implementations wrap these sentinel errors with additional context:

return fmt.Errorf("postgres: get scan %s: %w", scanID, shield.ErrScanNotFound)

Check errors using errors.Is:

result, err := eng.GetScan(ctx, scanID)
if errors.Is(err, shield.ErrScanNotFound) {
    // handle not found
}