public async Task ExecuteAsync_MultiplePolicies_WorkAsExpected()
{
// cache
string url = "/api/cache";
string result = await _policyWrapper.ExecuteAsync(async context => await _client.GetStringAsync(url), new Context("CacheKey1")); // typically cache key would be dynamic
string result2 = await _policyWrapper.ExecuteAsync(async context => await _client.GetStringAsync(url), new Context("CacheKey1"));
Assert.IsTrue(!string.IsNullOrWhiteSpace(result));
Assert.AreEqual(result, result2);
// inner timeout (500 ms), retry (5), outer timeout (this will exception as the inner timeouts will be retried enough times to trigger outer timeout)
url = "/api/timeout/slow";
bool timeout = false;
try
{
await _policyWrapper.ExecuteAsync(async context => await _client.GetStringAsync(url), new Context("CacheKey2"));
}
catch (TimeoutRejectedException)
{
timeout = true;
}
Assert.IsTrue(timeout);
// trying this again will trip circuit breaker before we get a chance to hit the outer timeout
bool circuitIsBroken = false;
try
{
string result3 = await _policyWrapper.ExecuteAsync(async context => await _client.GetStringAsync(url), new Context("CacheKey3"));
}
catch (BrokenCircuitException)
{
circuitIsBroken = true;
}
Assert.IsTrue(circuitIsBroken);
// lets try a fallback
url = "/api/circuitbreaker/success";
var fallbackWrapper = FallbackPolicy <string>
.Handle <Exception>()
.FallbackAsync(context => Task.Run(() => "default"))
.WrapAsync(_policyWrapper);
string result4 = await fallbackWrapper.ExecuteAsync(async context => await _client.GetStringAsync(url), new Context("CacheKey4"));
Assert.AreEqual("default", result4);
// let circuit breaker reset
Task.Delay(3000).Wait();
string result5 = await fallbackWrapper.ExecuteAsync(async context => await _client.GetStringAsync(url), new Context("CacheKey5"));
Assert.IsTrue(!string.IsNullOrWhiteSpace(result5));
Assert.AreNotEqual("default", result5);
}
private async Task <string> CallApiWithFallback(string action, Func <Task <string> > fallback)
{
var fallbackWrapper = FallbackPolicy <string>
.Handle <Exception>()
.FallbackAsync(context => fallback())
.WrapAsync(_circuitBreaker);
string response = await fallbackWrapper.ExecuteAsync(async context => await _client.GetStringAsync($"{_url}/{action}"), new Context());
return(response);
}