Resilience
in Software Architecture
Definition(s)
- the capacity to recover quickly from difficulties; toughness.
- the ability of a substance or object to spring back into shape; elasticity.
Resilience in Software Architecture
The Ability to recover (gracefully) with certain (unexpected) types/points of failure whilst remaining completely functional from the customer perspective view.
Sometimes Resiliency is called Recoverability.
Resilience in Frontend Matters
Autonomously working components
and external data make the need of adding up protective (resilient) layers.
Resilience in Frontend Matters
- Proxies (!)
- safeGetters
- Facebook idx @compile-time
- Error Boundaries (e.g. try-catch, Promises, React EB, ...)
- Content Validation (e.g. checking if HTTP Request returned an image type)
- ....
- TypeScript
--> only helps Resilience in a closed ecosystem!
Resilience in Frontend Matters
The Costs of Resiliency
and how to reduce those
Resilience in Frontend Matters
Finite State Machines can help you cutting down the options
Costs of Resiliency
Use EVERY point as a point of failure
Resilience in Frontend Matters
Unit tests can cover 100% what is beyond parameter verification.
Costs of Resiliency
function someFunction(param1, param2) {
// we are not able to cover all cases of params.
// we can only ensure that a certain format is provided
if (ensureValidation(param1)) {
...
}
if (ensureOtherValidation(param2)) {
...
}
// everything beyond here is potentially trustworthy
// and can be 100% covered by unit tests
}Resilience in Frontend Matters
Coverage with unit tests is easier when you have abstraction layers
Costs of Resiliency
@import unitTestedLayer from '...';
export function abc() {
/// ....
unitTestedLayer.action();
}Otherwise you introduce costs per module
Resilience in Frontend Matters
Downside
Costs of Resiliency
Abstraction Levels don't safe you from having costs per module on a runtime level
- neither does not having abstraction levels
Resilience in Frontend Matters
Overcome breaking Web APIs with Messaging
Costs of Resiliency
// instead of
some.external.api.action();
// use
publishMessage('i.need.external.api.action');Resilience in Frontend Matters
When doing messaging: Set Response Limits
Costs of Resiliency
publishMessage('i.need.external.api.action', successHandler);
const clear = setTimeout(errorHandler, 5000);
function successHandler() {
clearTimeout(clear);
}Resilience in Frontend Matters
Resilience starts with Concept and Design!
Resilience in Frontend Matters
Proxy Sample
Resilience in Frontend Matters
How far do you go?
Resilience
By activenode
