public async Task AddCircuitBreakerPolicy_RandomHandledHttpErrors_OnlyBreakWhenConsecutiveHandledErrorsDetected()
{
var statusCodeInOrder = new[] { HttpStatusCode.RequestTimeout, HttpStatusCode.RequestTimeout, HttpStatusCode.TooManyRequests,
HttpStatusCode.RequestTimeout, HttpStatusCode.RequestTimeout, HttpStatusCode.RequestTimeout, HttpStatusCode.RequestTimeout };
var exceptionAllowedBeforeBreaking = 3;
var circuitBreakDuration = 400;
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Returns((int count) => Task.FromResult(new HttpResponseMessage(statusCodeInOrder[count])));
var mockInstance = mockInterface.Object;
var policy = HttpClientPollyPolicy.Initialise()
.AddCircuitBreakerPolicy(exceptionAllowedBeforeBreaking, TimeSpan.FromMilliseconds(circuitBreakDuration))
.Build();
Func <int, Task <HttpResponseMessage> > action = (int index) => policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(index));
Func <Task <HttpResponseMessage> > actionNoParam = () => policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
Assert.Equal(statusCodeInOrder[0], (await action(0)).StatusCode);
Assert.Equal(statusCodeInOrder[1], (await action(1)).StatusCode);
Assert.Equal(statusCodeInOrder[2], (await action(2)).StatusCode);
Assert.Equal(statusCodeInOrder[3], (await action(3)).StatusCode);
Assert.Equal(statusCodeInOrder[4], (await action(4)).StatusCode);
Assert.Equal(statusCodeInOrder[5], (await action(5)).StatusCode);
await Assert.ThrowsAsync <BrokenCircuitException <HttpResponseMessage> >(actionNoParam);
await Task.Delay(circuitBreakDuration);
Assert.Equal(statusCodeInOrder[6], (await action(6)).StatusCode);
}
public async Task AddCircuitBreakerPolicy_HavingRepeatedHttpRequestException_ActivateCircuitBreak()
{
var exceptionAllowedBeforeBreaking = 2;
var circuitBreakDuration = 400;
var message = "sample exception";
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(1))
.Throws(new HttpRequestException(message));
mockInterface.Setup(exp => exp.DoSomethingAsync(2))
.Returns(Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)));
var mockInstance = mockInterface.Object;
var policy = HttpClientPollyPolicy.Initialise()
.AddCircuitBreakerPolicy(exceptionAllowedBeforeBreaking, TimeSpan.FromMilliseconds(circuitBreakDuration))
.Build();
Func <int, Task <HttpResponseMessage> > action = count => policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(count));
await Assert.ThrowsAsync <HttpRequestException>(() => action(1));
await Assert.ThrowsAsync <HttpRequestException>(() => action(1));
await Assert.ThrowsAsync <BrokenCircuitException>(() => action(1));
await Task.Delay(circuitBreakDuration);
//Half Open goes to Close
var result = await action(2);
Assert.Equal(HttpStatusCode.OK, result.StatusCode);
await Assert.ThrowsAsync <HttpRequestException>(() => action(1));
}
public async Task AddCircuitBreakerPolicy_HavingRepeatedUnhandledException_DoesNotActivateCircuitBreak(Type exceptionType)
{
var exceptionAllowedBeforeBreaking = 2;
var circuitBreakDuration = 400;
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Throws(Activator.CreateInstance(exceptionType) as Exception);
var mockInstance = mockInterface.Object;
var policy = HttpClientPollyPolicy.Initialise()
.AddCircuitBreakerPolicy(exceptionAllowedBeforeBreaking, TimeSpan.FromMilliseconds(circuitBreakDuration))
.Build();
Func <Task <HttpResponseMessage> > action = () => policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
await Assert.ThrowsAsync(exceptionType, action);
await Assert.ThrowsAsync(exceptionType, action);
await Assert.ThrowsAsync(exceptionType, action);
await Assert.ThrowsAsync(exceptionType, action);
await Task.Delay(circuitBreakDuration);
await Assert.ThrowsAsync(exceptionType, action);
}
public async Task HttpClientPolicy_CombinePolicies_BehavesAccordingToPolicy()
{
var retryCount = 3;
var exceptionAllowedBeforeBreaking = retryCount + 2;
var circuitBreakDurationInMs = 10000;
var timeoutInSeconds = 25;
var foo = new FooStub();
var policy = HttpClientPollyPolicy.Initialise()
.AddWaitRetryPolicy(retryCount)
.AddFallbackPolicy(() => foo.FakeCallback())
.AddCircuitBreakerPolicy(exceptionAllowedBeforeBreaking, TimeSpan.FromMilliseconds(circuitBreakDurationInMs))
.AddTimeoutPolicy(timeoutInSeconds)
.Build();
Func <bool, int?, Task <HttpResponseMessage> > barAsync = (bool returnFailureMessage, int?fakeTimeoutInSeconds) => policy.ExecuteAsync(() => foo.BarAsync(returnFailureMessage, fakeTimeoutInSeconds));
var result = await barAsync(true, null);
int barAsyncMethodInvocationCount = retryCount + 1;
Assert.Equal(HttpStatusCode.BadRequest, result.StatusCode);
result = await barAsync(true, null);
barAsyncMethodInvocationCount++;
int callbackMethodInvocationCount = 3;
Assert.Equal(HttpStatusCode.BadRequest, result.StatusCode);
await Task.Delay(circuitBreakDurationInMs);
//Return unhandled error code to transition circuit from half-open to close
result = await barAsync(false, null);
barAsyncMethodInvocationCount++;
Assert.Equal(HttpStatusCode.OK, result.StatusCode);
result = await barAsync(true, null);
barAsyncMethodInvocationCount += retryCount + 1;
Assert.Equal(HttpStatusCode.BadRequest, result.StatusCode);
result = await barAsync(true, timeoutInSeconds);
barAsyncMethodInvocationCount++;
callbackMethodInvocationCount++;
Assert.Equal(HttpStatusCode.BadRequest, result.StatusCode);
Assert.Equal(callbackMethodInvocationCount, foo.FallbackCount);
Assert.Equal(barAsyncMethodInvocationCount, foo.BarAsyncCount);
}
public async Task AddWaitRetryPolicy_CallSucceedInitially_DoesNotRetry()
{
var policy = HttpClientPollyPolicy.Initialise()
.AddWaitRetryPolicy(2)
.Build();
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Returns(Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)));
var mockInstance = mockInterface.Object;
var result = await policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
Assert.Equal(HttpStatusCode.OK, result.StatusCode);
mockInterface.Verify(exp => exp.DoSomethingAsync(It.IsAny <int>()), Times.Exactly(1));
}
public async Task AddWaitRetryPolicy_ReturnHttpTransientError_RetryUptoCount(HttpStatusCode transientStatusCode)
{
var retryCount = 2;
var policy = HttpClientPollyPolicy.Initialise()
.AddWaitRetryPolicy(retryCount)
.Build();
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Returns(Task.FromResult(new HttpResponseMessage(transientStatusCode)));
var mockInstance = mockInterface.Object;
var result = await policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
Assert.Equal(transientStatusCode, result.StatusCode);
mockInterface.Verify(exp => exp.DoSomethingAsync(It.IsAny <int>()), Times.Exactly(retryCount + 1));
}
public async Task AddTimeoutPolicy_OperationCompleteWithinTimeoutPeriod_CompleteSuccessfully()
{
var timeoutInMilliseconds = 1000;
var policy = HttpClientPollyPolicy.Initialise()
.AddTimeoutPolicy(timeoutInMilliseconds / 1000)
.Build();
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.ReturnsAsync(new HttpResponseMessage(HttpStatusCode.OK), TimeSpan.FromMilliseconds(timeoutInMilliseconds / 2));
var mockInstance = mockInterface.Object;
var result = await policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
Assert.Equal(HttpStatusCode.OK, result.StatusCode);
mockInterface.Verify(exp => exp.DoSomethingAsync(It.IsAny <int>()), Times.Exactly(1));
}
public async Task AddWaitRetryPolicy_ThrowNullException_DoesNotRetry()
{
var retryCount = 2;
var policy = HttpClientPollyPolicy.Initialise()
.AddWaitRetryPolicy(retryCount)
.Build();
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Throws(new NullReferenceException());
var mockInstance = mockInterface.Object;
Func <Task <HttpResponseMessage> > action = () => policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
await Assert.ThrowsAsync <NullReferenceException>(action);
mockInterface.Verify(exp => exp.DoSomethingAsync(It.IsAny <int>()), Times.Exactly(1));
}
public async Task AddTimeoutPolicy_OperationExceedTimeoutPeriod_ThrowsPollyTimeoutRejectedException()
{
var timeoutInMilliseconds = 1000;
var policy = HttpClientPollyPolicy.Initialise()
.AddTimeoutPolicy(timeoutInMilliseconds / 1000)
.Build();
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.ReturnsAsync(new HttpResponseMessage(HttpStatusCode.OK), TimeSpan.FromMilliseconds(timeoutInMilliseconds + 20));
var mockInstance = mockInterface.Object;
Func <Task <HttpResponseMessage> > action = () => policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
await Assert.ThrowsAsync <TimeoutRejectedException>(action);
mockInterface.Verify(exp => exp.DoSomethingAsync(It.IsAny <int>()), Times.Exactly(1));
}
public async Task AddFallbackPolicy_WithUnhandledHttpErrors_DoesNotInvokeFallbackMethod(HttpStatusCode httpStatusCode)
{
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Returns(Task.FromResult(new HttpResponseMessage(httpStatusCode)));
mockInterface.Setup(exp => exp.FakeCallback())
.Returns(Task.FromResult(new HttpResponseMessage(HttpStatusCode.Accepted)));
var mockInstance = mockInterface.Object;
var policy = HttpClientPollyPolicy.Initialise()
.AddFallbackPolicy(() => mockInstance.FakeCallback())
.Build();
var result = await policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
Assert.Equal(httpStatusCode, result.StatusCode);
mockInterface.Verify(exp => exp.DoSomethingAsync(It.IsAny <int>()), Times.Exactly(1));
mockInterface.Verify(exp => exp.FakeCallback(), Times.Never);
}
public async Task AddFallbackPolicy_WithHandledExceptions_InvokeFallbackMethod(Type exceptionType)
{
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Throws(Activator.CreateInstance(exceptionType) as Exception);
mockInterface.Setup(exp => exp.FakeCallback())
.Returns(Task.FromResult(new HttpResponseMessage(HttpStatusCode.Accepted)));
var mockInstance = mockInterface.Object;
var policy = HttpClientPollyPolicy.Initialise()
.AddFallbackPolicy(() => mockInstance.FakeCallback())
.Build();
var result = await policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
Assert.Equal(HttpStatusCode.Accepted, result.StatusCode);
mockInterface.Verify(exp => exp.DoSomethingAsync(It.IsAny <int>()), Times.Exactly(1));
mockInterface.Verify(exp => exp.FakeCallback(), Times.Exactly(1));
}
public async Task AddCircuitBreakerPolicy_HavingRepeatedUnHandledHttpErrors_DoesNotActivateCircuitBreak(HttpStatusCode httpStatusCode)
{
var exceptionAllowedBeforeBreaking = 2;
var circuitBreakDuration = 400;
var mockInterface = new Mock <IFakeInterface>();
mockInterface.Setup(exp => exp.DoSomethingAsync(It.IsAny <int>()))
.Returns(Task.FromResult(new HttpResponseMessage(httpStatusCode)));
var mockInstance = mockInterface.Object;
var policy = HttpClientPollyPolicy.Initialise()
.AddCircuitBreakerPolicy(exceptionAllowedBeforeBreaking, TimeSpan.FromMilliseconds(circuitBreakDuration))
.Build();
Func <Task <HttpResponseMessage> > action = () => policy.ExecuteAsync(() => mockInstance.DoSomethingAsync(3));
Assert.Equal(httpStatusCode, (await action()).StatusCode);
Assert.Equal(httpStatusCode, (await action()).StatusCode);
Assert.Equal(httpStatusCode, (await action()).StatusCode);
await Task.Delay(circuitBreakDuration);
Assert.Equal(httpStatusCode, (await action()).StatusCode);
}