4. Combining Policies to Protect Against Many Types of Failure

Question 1

What does wrapping allow us to do in regards to resilience?

Answer 1

They allow us to combine multiple layers of resilience when calling a remote service.

Question 2

What does wrapping mean for us when it comes to code readability?

Answer 2

Wrapping can help us make our code shorter and easier to read.

Question 3

What does wrapping offer us in terms of code reuse?

Answer 3

It encourages the reuse of combinations of policies.

Question 4

Which one does wrapping work with — generic or non-generic policies?

Answer 4

Both.

Question 5

What can be said about wrapping policies when it comes to policy interfaces?

Answer 5

Wrapping can be used with policy interfaces instead of concrete types.

Question 6

What’s can be said about the syntactical difference between wrapping generic policies vs wrapping them together with non-generic policies?

Answer 6

Wrapping generic policies is less complex, whereas wrapping them together with non-generic policies is slightly more complex.

Question 7

What interface can you use for policy wraps to be able to unit test them?

Answer 7

The IPolicyWrap interface.

Question 8

How do we wrap generic policies?

Answer 8

By using the Wrap or WrapAsync method (depending on the synchronicity of policies) of the Policy method.

Policy.WrapAsync(
     _fallbackPolicy, _retryPolicy, _timeoutPolicy);

Question 9

How do we wrap generic and non-generic policies together?

Answer 9

By using the .Wrap or .WrapAsync method of Policy objects.

_fallbackPolicy
    .WrapAsync(_retryPolicy
        .WrapAsync(_timeoutPolicy));