Architectural decisions and their impact

There are quite a few talks out there explaining architectural patterns, but it is harder to find examples from actual projects and more specifically, making architectural changes in an existing project.

This talk aims to fill this gap by showing how two major architectural problems were identified, how the impacted the code and finally what we changed and how it improved the code. Since we use an open source project for this, you can even follow along by checking out the old versions, looking at the pull requests and obviously the current state for the result.

Transcript

1. Architektur-
   entscheidungen
   und ihre Folgen
   The Good
   The Bad
   The Ugly
   

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2. Denis Brumann
   Solutions Architect
   Current Maintainer of Deptrac
   denis.brumann@qossmic.com
   @dbrumann
   

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3. Command Line
   API Web App
   What kind of application is Deptrac?
   

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4. Command Line
   API Web App
   What kind of application is Deptrac?
   

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5. Command Line
   API Web App
   Interactive
   Non-Interactive
   What kind of application is Deptrac?
   

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9. Web apps and APIs
   https://my-app.com/
   MyApp DB
   MyApp
   

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10. https://foo.my-app.com/
    Interactive runtime in web apps and APIs
    https://acme.my-app.com/ ACME DB
    Foo DB
    MyApp
    

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11. https://foo.my-app.com/
    Interactive runtime in web apps and APIs
    https://acme.my-app.com/ ACME DB
    Foo DB
    MyApp
    Tenant-Aware
    Multi-Portal
    

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12. Warning Signs
    Services creating other services
    (usage of new in code)
    Service Locator or factory-usage
    Config-objects (or arrays) being passed through
    

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16. Possible Problems
    Runtime errors (invalid context,
    misconfigured services)
    Debugging is more difficult
    (which service/config was used?)
    More coupling & complexity
    

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18. Lesson
    Avoid creating/configuring services at runtime
    

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27. nikic/php-parser
    is only used here
    

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28. nikic/php-parser
    is only used here
    Deptrac’s
    own structure
    

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32. No longer contains
    dependency-references
    

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35. Possible Benefits
    Switching dependencies is easier
    Refactoring is more contained
    Easier extraction
    

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39. Possible Problems
    Mapping between objects
    can become annoying
    More code/duplication
    “Wrong” layers add complexity
    

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40. Lesson
    Isolating layers helps contain changes
    and makes switching out parts easier
    

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