Add giveUpAfter(timeout:) modifier, remove retryOn(*) modifiers (#23)

Author: PierreMardon

README.md

@@ -11,19 +11,14 @@ var conditionPublisher: AnyPublisher<Bool, Never>
 let coldRetrier = withExponentialBackoff() 
     // Fetch only when you've got network and your user is authenticated for example
     .onlyWhen(conditionPublisher)
-    // Ensure your retrier fails on some conditions
+    // Ensure your retrier gives up on some conditions
     .giveUpAfter(maxAttempts: 10)
+    .giveUpAfter(timeout: 30)
     .giveUpOnErrors {
         $0 is MyFatalError
     }
-    // Ensure your retrier won't give up on some errors
-    .retryOnErrors {
-        $0 is MyTmpError
-    }
 ```
 
-**All giveUp / retry modifiers are evaluated in reversed order.**
-
 [Exponential backoff](https://aws.amazon.com/fr/blogs/architecture/exponential-backoff-and-jitter/) with
 full jitter is the default and recommended algorithm to fetch from a backend. 
 
@@ -60,12 +55,10 @@ If you don't repeat, you can wait for a single value in a concurrency context
 let value = try await withExponentialBackoff() 
     .onlyWhen(conditionPublisher)
     .giveUpAfter(maxAttempts: 10)
+    .giveUpAfter(timeout: 30)
     .giveUpOnErrors {
         $0 is MyFatalError
     }
-    .retryOnErrors {
-        $0 is MyTmpError
-    }
     .execute {
         try await api.fetchValue()
     }
@@ -120,6 +113,7 @@ case, guarantees such as the previous one are no longer valid.
 - Condition publishers events will be processed on `DispatchQueue.main`, but won't be delayed if they're already 
 emitted on it.
 - After a retrier is interrupted then resumed by its `conditionPublisher`, its policy is reused from start.
+Consequently `giveUpAfter(maxAttempts:)` and `giveUpAfter(timeout:)` checks are applied to the current trial, ignoring previous ones.
 
 ## Retry Policies
 
@@ -134,9 +128,7 @@ You can especially choose the jitter type between `none`, `full` (default) and `
 
 **ConstantDelayRetryPolicy** does what you expect, just waiting for a fixed amount of time.
 
-You can add failure conditions using `giveUp*()` functions, and bypass these conditions using `retry*()` functions.
-
-All giveUp / retry modifiers are evaluated in reversed order.
+You can add failure conditions using `giveUp*()` functions.
 
 ### Homemade policy
 

Sources/SwiftRetrier/Core/Model/Policies/AttemptFailure.swift

@@ -1,6 +1,7 @@
 import Foundation
 
 public struct AttemptFailure {
+    public let trialStart: Date
     public let index: UInt
     public let error: Error
 }

Sources/SwiftRetrier/Core/PolicyBuilding/RetryOnPolicyWrapper.swift

@@ -10,6 +10,13 @@ public extension RetryPolicy {
         GiveUpOnPolicyWrapper(wrapped: self, giveUpCriterium: { $0.index >= maxAttempts - 1})
     }
 
+    func giveUpAfter(timeout: TimeInterval) -> RetryPolicy {
+        GiveUpOnPolicyWrapper(wrapped: self, giveUpCriterium: {
+            let nextAttemptStart = Date().addingTimeInterval(retryDelay(for: $0))
+            return nextAttemptStart >= $0.trialStart.addingTimeInterval(timeout)
+        })
+    }
+
     func giveUpOnErrors(matching finalErrorCriterium: @escaping (Error) -> Bool) -> RetryPolicy {
         GiveUpOnPolicyWrapper(wrapped: self, giveUpCriterium: { finalErrorCriterium($0.error) })
     }

Sources/SwiftRetrier/Core/PolicyBuilding/RetryPolicy+GiveUpOn.swift

@@ -78,8 +78,10 @@ public class ConditionalRetrier<Output>: SingleOutputRetrier {
         guard let retrier else { return }
         retrierSubscription?.cancel()
         retrier.cancel()
+        subject.send(.attemptFailure(AttemptFailure(trialStart: retrier.trialStart,
+                                                    index: attemptIndex,
+                                                    error: CancellationError())))
         self.retrier = nil
-        subject.send(.attemptFailure(AttemptFailure(index: attemptIndex, error: CancellationError())))
         attemptIndex += 1
     }
 
@@ -97,7 +99,9 @@ public class ConditionalRetrier<Output>: SingleOutputRetrier {
                 switch $0 {
                     // Catch attempt failure to adjust attempt index
                 case .attemptFailure(let attemptFailure):
-                    event = .attemptFailure(AttemptFailure(index: attemptIndex, error: attemptFailure.error))
+                    event = .attemptFailure(AttemptFailure(trialStart: attemptFailure.trialStart,
+                                                           index: attemptIndex,
+                                                           error: attemptFailure.error))
                     attemptIndex += 1
                     // Remember final event for future await on value
                 case .attemptSuccess:

Sources/SwiftRetrier/Core/PolicyBuilding/RetryPolicy+RetryOn.swift

@@ -12,6 +12,7 @@ import Combine
 /// emits a completion embedding the same error then finishes.
 public class SimpleRetrier<Output>: SingleOutputRetrier {
 
+    public let trialStart = Date()
     private let subject = PassthroughSubject<RetrierEvent<Output>, Never>()
     private var task: Task<Output, Error>!
 
@@ -56,11 +57,13 @@ public class SimpleRetrier<Output>: SingleOutputRetrier {
                         await finish(with: result)
                         return result
                     } catch {
-                        let attemptFailure = AttemptFailure(index: attemptIndex, error: error)
+                        let attemptFailure = AttemptFailure(trialStart: trialStart, index: attemptIndex, error: error)
                         await sendAttemptFailure(attemptFailure)
                         try Task.checkCancellation()
                         let retryDecision = await MainActor.run { [attemptIndex] in
-                            policy.shouldRetry(on: AttemptFailure(index: attemptIndex, error: error))
+                            policy.shouldRetry(on: AttemptFailure(trialStart: trialStart,
+                                                                  index: attemptIndex,
+                                                                  error: error))
                         }
                         switch retryDecision {
                         case .giveUp:

Sources/SwiftRetrier/Core/Retriers/ConditionalRetrier.swift

@@ -19,20 +19,16 @@ public extension ColdRepeater {
         return ColdRepeater(policy: policy, repeatDelay: repeatDelay, conditionPublisher: conditionPublisher)
     }
 
-    func giveUpOnErrors(matching finalErrorCriterium: @escaping (Error) -> Bool) -> ColdRepeater {
-        let policy = policy.giveUpOnErrors(matching: finalErrorCriterium)
+    func giveUpAfter(timeout: TimeInterval) -> ColdRepeater {
+        let policy = policy.giveUpAfter(timeout: timeout)
         return ColdRepeater(policy: policy, repeatDelay: repeatDelay, conditionPublisher: conditionPublisher)
     }
 
-    func retry(on retryCriterium: @escaping (AttemptFailure) -> Bool) -> ColdRepeater {
-        let policy = RetryOnPolicyWrapper(wrapped: policy, retryCriterium: retryCriterium)
+    func giveUpOnErrors(matching finalErrorCriterium: @escaping (Error) -> Bool) -> ColdRepeater {
+        let policy = policy.giveUpOnErrors(matching: finalErrorCriterium)
         return ColdRepeater(policy: policy, repeatDelay: repeatDelay, conditionPublisher: conditionPublisher)
     }
 
-    func retryOnErrors(matching retryCriterium: @escaping (Error) -> Bool) -> ColdRepeater {
-        retry(on: { retryCriterium($0.error) })
-    }
-
     func onlyWhen<P>(
         _ conditionPublisher: P
     ) -> ColdRepeater where P: Publisher, P.Output == Bool, P.Failure == Never {

Sources/SwiftRetrier/Core/Retriers/SimpleRetrier.swift

@@ -18,20 +18,16 @@ public extension ColdRetrier {
         return ColdRetrier(policy: policy, conditionPublisher: conditionPublisher)
     }
 
-    func giveUpOnErrors(matching finalErrorCriterium: @escaping (Error) -> Bool) -> ColdRetrier {
-        let policy = policy.giveUpOnErrors(matching: finalErrorCriterium)
+    func giveUpAfter(timeout: TimeInterval) -> ColdRetrier {
+        let policy = policy.giveUpAfter(timeout: timeout)
         return ColdRetrier(policy: policy, conditionPublisher: conditionPublisher)
     }
 
-    func retry(on retryCriterium: @escaping (AttemptFailure) -> Bool) -> ColdRetrier {
-        let policy = RetryOnPolicyWrapper(wrapped: policy, retryCriterium: retryCriterium)
+    func giveUpOnErrors(matching finalErrorCriterium: @escaping (Error) -> Bool) -> ColdRetrier {
+        let policy = policy.giveUpOnErrors(matching: finalErrorCriterium)
         return ColdRetrier(policy: policy, conditionPublisher: conditionPublisher)
     }
 
-    func retryOnErrors(matching retryCriterium: @escaping (Error) -> Bool) -> ColdRetrier {
-        retry(on: { retryCriterium($0.error) })
-    }
-
     func onlyWhen<P>(
         _ conditionPublisher: P
     ) -> ColdRetrier where P: Publisher, P.Output == Bool, P.Failure == Never {