// Single exception type
Policy
  .Handle<DivideByZeroException>()

// Single exception type with condition
Policy
  .Handle<SqlException>(ex => ex.Number == 1205)

// Multiple exception types
Policy
  .Handle<DivideByZeroException>()
  .Or<ArgumentException>()

// Multiple exception types with condition
Policy
  .Handle<SqlException>(ex => ex.Number == 1205)
  .Or<ArgumentException>(ex => ex.ParamName == "example")

// Retry once
Policy
  .Handle<DivideByZeroException>()
  .Retry()

// Retry multiple times
Policy
  .Handle<DivideByZeroException>()
  .Retry(3)

// Retry multiple times, calling an action on each retry 
// with the current exception and retry count
Policy
    .Handle<DivideByZeroException>()
    .Retry(3, (exception, retryCount) =>
    {
        // do something 
    });

// Retry multiple times, calling an action on each retry 
// with the current exception, retry count and context 
// provided to Execute()
Policy
    .Handle<DivideByZeroException>()
    .Retry(3, (exception, retryCount, context) =>
    {
        // do something 
    });

// Retry forever
Policy
  .Handle<DivideByZeroException>()
  .RetryForever()

// Retry forever, calling an action on each retry with the 
// current exception
Policy
  .Handle<DivideByZeroException>()
  .RetryForever(exception =>
  {
        // do something       
  });

// Retry forever, calling an action on each retry with the
// current exception and context provided to Execute()
Policy
  .Handle<DivideByZeroException>()
  .RetryForever((exception, context) =>
  {
        // do something       
  });

// Retry, waiting a specified duration between each retry
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(new[]
  {
    TimeSpan.FromSeconds(1),
    TimeSpan.FromSeconds(2),
    TimeSpan.FromSeconds(3)
  });

// Retry, waiting a specified duration between each retry, 
// calling an action on each retry with the current exception
// and duration
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(new[]
  {
    TimeSpan.FromSeconds(1),
    TimeSpan.FromSeconds(2),
    TimeSpan.FromSeconds(3)
  }, (exception, timeSpan) => {
    // do something    
  }); 

// Retry, waiting a specified duration between each retry, 
// calling an action on each retry with the current exception, 
// duration and context provided to Execute()
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(new[]
  {
    TimeSpan.FromSeconds(1),
    TimeSpan.FromSeconds(2),
    TimeSpan.FromSeconds(3)
  }, (exception, timeSpan, context) => {
    // do something    
  });

// Retry, waiting a specified duration between each retry, 
// calling an action on each retry with the current exception, 
// duration, retry count, and context provided to Execute()
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(new[]
  {
    TimeSpan.FromSeconds(1),
    TimeSpan.FromSeconds(2),
    TimeSpan.FromSeconds(3)
  }, (exception, timeSpan, retryCount, context) => {
    // do something    
  });

// Retry a specified number of times, using a function to 
// calculate the duration to wait between retries based on 
// the current retry attempt (allows for exponential backoff)
// In this case will wait for
//  2 ^ 1 = 2 seconds then
//  2 ^ 2 = 4 seconds then
//  2 ^ 3 = 8 seconds then
//  2 ^ 4 = 16 seconds then
//  2 ^ 5 = 32 seconds
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(5, retryAttempt => 
	TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)) 
  );

// Retry a specified number of times, using a function to 
// calculate the duration to wait between retries based on 
// the current retry attempt, calling an action on each retry 
// with the current exception, duration and context provided 
// to Execute()
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(
    5, 
    retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)), 
    (exception, timeSpan, context) => {
      // do something
    }
  );

// Retry a specified number of times, using a function to 
// calculate the duration to wait between retries based on 
// the current retry attempt, calling an action on each retry 
// with the current exception, duration, retry count, and context 
// provided to Execute()
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(
    5, 
    retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)), 
    (exception, timeSpan, retryCount, context) => {
      // do something
    }
  );

// Wait and retry forever
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetryForever(retryAttempt => 
	TimeSpan.FromSeconds(Math.Pow(2, retryAttempt))
    );

// Wait and retry forever, calling an action on each retry with the 
// current exception and the time to wait
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetryForever(
    retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)),    
    (exception, timespan) =>
    {
        // do something       
    });

// Wait and retry forever, calling an action on each retry with the
// current exception, time to wait, and context provided to Execute()
Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetryForever(
    retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)),    
    (exception, timespan, context) =>
    {
        // do something       
    });

// Break the circuit after the specified number of exceptions
// and keep circuit broken for the specified duration.
Policy
    .Handle<DivideByZeroException>()
    .CircuitBreaker(2, TimeSpan.FromMinutes(1));

// Break the circuit after the specified number of exceptions
// and keep circuit broken for the specified duration,
// calling an action on change of circuit state.
Action<Exception, TimeSpan> onBreak = (exception, timespan) => { ... };
Action onReset = () => { ... };
CircuitBreakerPolicy breaker = Policy
    .Handle<DivideByZeroException>()
    .CircuitBreaker(2, TimeSpan.FromMinutes(1), onBreak, onReset);

// Break the circuit after the specified number of exceptions
// and keep circuit broken for the specified duration,
// calling an action on change of circuit state,
// passing a context provided to Execute().
Action<Exception, TimeSpan, Context> onBreak = (exception, timespan, context) => { ... };
Action<Context> onReset = context => { ... };
CircuitBreakerPolicy breaker = Policy
    .Handle<DivideByZeroException>()
    .CircuitBreaker(2, TimeSpan.FromMinutes(1), onBreak, onReset);

// Monitor the circuit state, for example for health reporting.
CircuitState state = breaker.CircuitState;

/*
CircuitState.Closed - Normal operation. Execution of actions allowed.
CircuitState.Open - The automated controller has opened the circuit. Execution of actions blocked.
CircuitState.HalfOpen - Recovering from open state, after the automated break duration has expired. Execution of actions permitted. Success of subsequent action/s controls onward transition to Open or Closed state.
CircuitState.Isolated - Circuit held manually in an open state. Execution of actions blocked.
*/

// Manually open (and hold open) a circuit breaker - for example to manually isolate a downstream service.
breaker.Isolate(); 
// Reset the breaker to closed state, to start accepting actions again.
breaker.Reset(); 

// Break the circuit if, within any period of duration samplingDuration, 
// the proportion of actions resulting in a handled exception exceeds failureThreshold, 
// provided also that the number of actions through the circuit in the period
// is at least minimumThroughput.

Policy
    .Handle<DivideByZeroException>()
    .AdvancedCircuitBreaker(
        failureThreshold: 0.5, // Break on >=50% actions result in handled exceptions...
        samplingDuration: TimeSpan.FromSeconds(10), // ... over any 10 second period
        minimumThroughput: 8, // ... provided at least 8 actions in the 10 second period.
        durationOfBreak: TimeSpan.FromSeconds(30) // Break for 30 seconds.
                );

// Configuration overloads taking stage-change delegates are
// available as described for CircuitBreaker above.

// Circuit state monitoring and manual controls are
// available as described for CircuitBreaker above.

// Execute an action
var policy = Policy
              .Handle<DivideByZeroException>()
              .Retry();

policy.Execute(() => DoSomething());

// Execute an action passing arbitrary context data
var policy = Policy
    .Handle<DivideByZeroException>()
    .Retry(3, (exception, retryCount, context) =>
    {
        var methodThatRaisedException = context["methodName"];
		Log(exception, methodThatRaisedException);
    });

policy.Execute(
	() => DoSomething(),
	new Dictionary<string, object>() {{ "methodName", "some method" }}
);

// Execute a function returning a result
var policy = Policy
              .Handle<DivideByZeroException>()
              .Retry();

var result = policy.Execute(() => DoSomething());

// Execute a function returning a result passing arbitrary context data
var policy = Policy
    .Handle<DivideByZeroException>()
    .Retry(3, (exception, retryCount, context) =>
    {
        object methodThatRaisedException = context["methodName"];
        Log(exception, methodThatRaisedException)
    });

var result = policy.Execute(
    () => DoSomething(),
    new Dictionary<string, object>() {{ "methodName", "some method" }}
);

// You can of course chain it all together
Policy
  .Handle<SqlException>(ex => ex.Number == 1205)
  .Or<ArgumentException>(ex => ex.ParamName == "example")
  .Retry()
  .Execute(() => DoSomething());

var policyResult = Policy
              .Handle<DivideByZeroException>()
              .Retry()
              .ExecuteAndCapture(() => DoSomething());
/*              
policyResult.Outcome - whether the call succeeded or failed         
policyResult.FinalException - the final exception captured, will be null if the call succeeded
policyResult.ExceptionType - was the final exception an exception the policy was defined to handle (like DivideByZeroException above) or an unhandled one (say Exception). Will be null if the call succeeded.
policyResult.Result - if executing a func, the result if the call succeeded or the type's default value
*/

await Policy
  .Handle<SqlException>(ex => ex.Number == 1205)
  .Or<ArgumentException>(ex => ex.ParamName == "example")
  .RetryAsync()
  .ExecuteAsync(() => DoSomethingAsync());

// Try several times to retrieve from a uri, but support cancellation at any time.
CancellationToken cancellationToken = // ...
var policy = Policy
    .Handle<WebException>()
    .Or<HttpRequestException>()
    .WaitAndRetryAsync(new[] { 
        TimeSpan.FromSeconds(1), 
        TimeSpan.FromSeconds(2), 
        TimeSpan.FromSeconds(4) 
    });
var response = await policy.ExecuteAsync(ct => httpClient.GetAsync(uri, ct), cancellationToken);