kitura / circuitbreaker Goto Github PK

The pendingHalfOpen flag currently could cause a race condition. Add semaphore logic to prevent this issue.

Currently the fallback function is of type: AnyFallback<C> = (C) -> Void which allows for a variable number of arguments to be passed by the client when calling the fallback function. The goal is to force the first argument in the list to be of type BreakerError to notify the client if the fallback was called because of a timeout or a fastFail.

For some reason making AnyFallback<C> = (BreakerError, C) -> Void will not allow C to have a variable number of arguments. Need to find a way to fix this issue.

Currently causing dependency graph conflicts.

This seems to be a known issue and one that, in theory, has already been addressed (see #16). But I'm still having issues with the signature for, and invocation of, the fallback function.

The README indicates that the fallback functions's signature should match

(<BreakerError, (fallbackArg1, fallbackArg2,...)>) -> Void

(Unless I'm missing something, the angle brackets are a typo in the README.)

and that the run method on CircuitBreaker should be called as follows:

breaker.run(commandArgs: (a: 10, b: 20), fallbackArgs: (msg: "Something went wrong."))

However, if I create a fallback with the signature (BreakerError, String) -> Void and try to invoke run as indicated above, I get the following error message:

error: cannot convert value of type '(msg: String)' to expected argument type 'String' 
breaker.run(commandArgs: (a: 12, b: 13), fallbackArgs: (msg: "This is a test"))                                                                                
                                                   ^~~~~~~~~~~~~~~~~~~~~~~                                                                                 
                                                                           as! String  

Further, if I create a fallback with the signature (BreakerError, String, String) -> Void and try to invoke run with breaker.run(commandArgs: (a: 10, b: 20), fallbackArgs: (msg, "First Message", msg2: "SecondMessage:)) I receive the following error:

error: cannot convert value of type '(Int, Int) -> Int' to expected argument type '(_) -> (_)'
let breaker = CircuitBreaker(command: myFunc, fallback: myFallback)                                                                                            
                                  ^~~~~~                                                

(Note: the error is with parsing the command, not the fallback.)

I can, however, successfully invoke run as follows:

 breaker.run(commandArgs: (a: 10, b: 20), fallbackArgs: "Something went wrong.")

I haven't yet finished working my way through the source, so that might clear up some mis-understanding on my part. Nevertheless, it seems that the README is definitely incorrect.
Also, it would be very useful to actually be able to pass more than one argument to the fallback function.

https://github.com/IBM-Swift/LoggerAPI

The library code is fine; we just need to update the test code. In the test code, let's use HeliumLogger as the concrete implementation for the logger.

Example build with the issue: https://travis-ci.com/IBM-Swift/CircuitBreaker/jobs/64731334

Running swift build and swift test locally results in no issues.

Swift Version: 3.0.2 RELEASE

The CircuitBreaker tests appear to have started intermittently failing in Travis. My suspicion is that this is test fragility rather than a real problem, but it ought to be investigated.

Example:
https://api.travis-ci.org/v3/job/461370473/log.txt

Test Case '-[CircuitBreakerTests.CircuitBreakerTests testStateCycle]' started.
/Users/travis/build/IBM-Swift/CircuitBreaker/Tests/CircuitBreakerTests/CircuitBreakerTests.swift:617: error: -[CircuitBreakerTests.CircuitBreakerTests testStateCycle] : XCTAssertEqual failed: ("closed") is not equal to ("open") - 
/Users/travis/build/IBM-Swift/CircuitBreaker/Tests/CircuitBreakerTests/CircuitBreakerTests.swift:620: error: -[CircuitBreakerTests.CircuitBreakerTests testStateCycle] : XCTAssertEqual failed: ("closed") is not equal to ("open") - 
/Users/travis/build/IBM-Swift/CircuitBreaker/Tests/CircuitBreakerTests/CircuitBreakerTests.swift:625: error: -[CircuitBreakerTests.CircuitBreakerTests testStateCycle] : XCTAssertEqual failed: ("closed") is not equal to ("halfopen") - 
Test Case '-[CircuitBreakerTests.CircuitBreakerTests testStateCycle]' failed (1.026 seconds).