Example of behaviour used for “Assert errors for behavior, not type”

error-behaviour.go

//
// See the post: https://tech.fog.fish/2022/07/05/assert-golang-errors-for-behavior.html 
//

// ErrorCodes provides a raw code originared by the failed package
type ErrorCode interface{ ErrorCode() string }

// ErrorType is the primary identifier (IRI) for the problem type, defined by the ontology 
type ErrorType interface{ ErrorType() string }

// Ephemeral is short lifespan error
type Ephemeral interface{ Ephemeral() bool }

// Timeout of the operation
type Timeout interface{ Timeout() time.Duration }

// PreConditionFailed when effect conditions are evaluated to false by the entity (see Optimistic Locking)
type PreConditionFailed interface { PreConditionFailed() bool }

// Conflict when effect could not be fulfilled due to a conflict with the current state of the target resource (see Optimistic Locking).
type Conflict interface{ Conflict() bool }

// Gone when effect is aborted due to availability of target resource (see Optimistic Locking).
type Gone interface{ Gone() bool }

// NotFound when target resource is not available
type NotFound interface { NotFound() string }

// HTTP Problem Details (RFC 7807)
type ProblemDetails interface {
  ErrorCode() string
  ErrorType() string
  ErrorInstance() string
  ErrorTitle() string
  ErrorDetail() string
}

// example of error wrapping function
func errSomeFailure(err error) error {
  var name string

  if pc, _, _, ok := runtime.Caller(1); ok {
    name = runtime.FuncForPC(pc).Name()
  }

  return fmt.Errorf("[%s] something failed: %w", name, err)
}


// Example of recovery function
func recoverEphemeral(err errors) bool {
  var e interface{ Ephemeral() bool }

  ok := errors.As(err, &e)
  return ok && e.Ephemeral()
}