Haven't you wished for try
to sometimes try a little harder? Meet retry
To run the example project, clone the repo, and run pod install
from the Example directory first.
The full test suite shows a variety of use cases.
NB: The sync retry
is not good for use on the main thread (because it will block it if you're having delays, etc). For the main thread it's better considering retryAsync
(more info below).
Default parameters - retry three times without any delay:
retry {
... do some throwing work ...
}
Catching the last error, and adding a defer block after all tries have finished - will keep trying maximum 10
times. You can use either of the final blocks or both:
retry (max: 10) {
... do some throwing work ...
}
.finalCatch {lastError in
print("This simply won't happen. Failed with: \(lastError)")
}
.finalDefer {
print("Finished trying")
}
Add 2
second delay between the retries:
retry (max: 5, retryStrategy: .delay(seconds: 2.0)) {
... do some throwing work ...
}
Implement any custom delay logic (below is multiplying the waiting time after each try):
retry (max: 5, retryStrategy: .custom {count, lastDelay in return (lastDelay ?? 1.0) * 2.0} ) {
... do some throwing work ...
}
Limit the number of retries based on any custom logic - if you return nil
from your custom strategy, retry
will stop trying:
retry (max: 5, retryStrategy: .custom {count,_ in return count > 3 ? nil : 0} ) {
... do some throwing work ...
}
The syntax for retryAsync
is exactly the same as for retry
. The difference in behavior is if the first try fails retryAsync
keeps trying asynchronously instead of blocking the current thread.
Retry is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod "Retry"
Retry is also available through Swift Package Manager. To install, add https://github.com/icanzilb/Retry.git
to your package manifest.
Since Retry is a swift3 library, you got to add this piece of code to your project's Podfile, to update your targets' swift language version:
post_install do |installer|
installer.pods_project.targets.each do |target|
target.build_configurations.each do |config|
config.build_settings['SWIFT_VERSION'] = '3.0'
config.build_settings['MACOSX_DEPLOYMENT_TARGET'] = '10.10'
end
end
end
Marin Todorov, 2016-present
Inspired by the retry operator in https://github.com/RxSwiftCommunity/RxSwiftExt
Retry is available under the MIT license. See the LICENSE file for more info.