BackOff<T> class

Object holding options for retrying a function.

With the default configuration functions will be retried up-to 7 times (8 attempts in total), sleeping 1st, 2nd, 3rd, ..., 7th attempt:

  1. 400 ms +/- 25%
  2. 800 ms +/- 25%
  3. 1600 ms +/- 25%
  4. 3200 ms +/- 25%
  5. 6400 ms +/- 25%
  6. 12800 ms +/- 25%
  7. 25600 ms +/- 25%

Example

final response = await backOff(
  // Make a GET request
  () => http.get('https://google.com').timeout(Duration(seconds: 5)),
  // Retry on SocketException or TimeoutException
  retryIf: (e) => e is SocketException || e is TimeoutException,
);
print(response.body);

Constructors

BackOff(FutureOr<T> func(), {Duration delayFactor = const Duration(milliseconds: 200), double randomizationFactor = 0.25, Duration maxDelay = const Duration(seconds: 30), int maxAttempts = 8, FutureOr<bool> retryIf(Object error, int attempt)?})
const

Properties

delayFactor → Duration
Delay factor to double after every attempt.
final
func → FutureOr<T> Function()
The Function to execute. If the function throws an error, it will be retried maxAttempts times with an increasing delay between each attempt up to maxDelay.
final
hashCode → int
The hash code for this object.
no setterinherited
maxAttempts → int
Maximum number of attempts before giving up, defaults to 8.
final
maxDelay → Duration
Maximum delay between retries, defaults to 30 seconds.
final
randomizationFactor → double
Percentage the delay should be randomized, given as fraction between 0 and 1.
final
retryIf → FutureOr<bool> Function(Object error, int attempt)?
Function to determine if a retry should be attempted.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

call() → Future<T>
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited