Architectual Considerations

The following is notes taken from watching Architectural session from "Uncle Bob" Martin

Take away's:

• Make sure you have a ubiquitous language about architectural characteristics(Reliability, Scalability, performance, etc) so that people can have a common dictionary to ensure people do not talk past each other

• KISS - How-To -- Don't try to meet all the "illities" - because as you add implementation for ilities, you add complexity

Business Requirements = Domain

Non-functional Requirements = Cross-Feature Requirements = Architecture Characteristics

• Reliability

• Scalability

• Performance

• Availability

Architectural Triad

Operational Architecture Characteristics

• Overlaps between distributed architecture & operational concerns

• Metrics:

  ○ Cumulative average response time - trigger alert when the average response times within a particular context exeeds 1400 ms)

  ○ Maximum Response Time - Trigger alert anytime max response time of selected requests exceeds 2000ms

  ○ Cumulative averge response time - trigger alert if response times continues to increase over 2 month period

Quality Arch Characteristics

• Fault Tolerance

• Reliability

  ○ Considered a composite characteristic - too braod to have a concrete objective. But it is the sum of a bunch of things that can be measured

  ○ Availability - using the nines chart

Process Arch Characteristics

• Agility - another composite characteristics

  ○ Deployability -

    § Measure  & track the number of actual hours spent to deploy
    § Measure & track failed deployments or errors resulting from deployment
    § Measure & track frequency of deployment

  ○ Testability

  ○ Modularity

Component coupling

• Afferent coupling - incoming - the degree to which other components are dependent on the target component

• Efferent coupling - outgoing - the degree to which the target component is dependent on other components

Coupling design

Uncle Bob's metric

• Too much abstractness & instability - zone of uselessness

• Too little abstraction & instability - zone of pain

Partitioning Services

• Technical partitioning

  • Presentation, business rules, persistent are each layers

• Domain paritioning

  • UI, module 1, module 2, …

Why Quantum?

• Operational view of architecture

• Holistic view of architecture

  • Database

  • User interface

• Useful for structural analysis

Consumer Driven Contracts:

• Martinfowler.com/articles/consumerDrivenContracts.html

• Pact

• Choas Testing:

  • Conformity Monkey - Used to ensure that charateristics are mapped to what they ned to me

  • Security monkey - ensuring you don't have any security characteristics

• ArchUnit -

  • https://archunit.org

  • https://Github.com/benmorris/netarchtest