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marp: true #theme: gaia theme: uncover class: invert author: "Ludger Solbach"

Overarch

Data Driven System Modelling

Ludger Solbach

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The problem

Understanding complex systems

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Overarch

• lightweight open source modelling
• data driven and text based -> developer friendly
• visualization
• queries
• reports

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Rationale

System models for

• thinking
• communication
• documentation
• querying

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Rationale

Drawing tools e.g. Visio, Gliffy, ExcaliDraw

• no model, only pretty pictures
• no reuse between diagrams

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Rationale

Commercial modelling tools

• e.g. Enterprise Architect, Magic Draw
• comprehensive but complex
• license needed

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Models

Elements of the system

• concept models, concept maps and glossaries
• system landscape and architecture, deployment
• use cases, state machines and class models

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Models

Models as data

• hierarchical models and element references
• composable / reusable
• extensible

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Views

Representations of the system

• selection of model elements for a specific
  • context
  • audience
  • level of detail

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Views

• C4 views for system architecture
  • system context, container, component
  • deployment, system landscape, dynamic

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Views

views as data

separation of models and views view specific customization of model elements

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Queries

• queries as data *

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Rendering

• PlantUML
  • C4 views, UML views
    • use case, state machine and class diagrams
  • styling and sprite support
• GraphViz
  • concept maps
• Markdown
  • glossaries
  • textual representations of graphical views

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Exporting

• exports
  • JSON if you need to process models with languages without EDN support
  • Structurizr experimental

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Example Model

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Example View

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Example Diagram

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Example Diagram

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Extensible Data Notation (EDN)

Similar to JSON but richer set of data literals Subset of Clojure

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EDN - Primitives

Numbers: 123 Strings: "Hello" Keywords: :keyword, :namespaced/keyword

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EDN - Data Structures

Vectors: ["a" "b" "c"] Sets: #{"a" "b" "c"} Maps: {:a "a" :b "b" :c "c"}

Data structures can be nested

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Modelling Example

#{ ; set of model elements
  {:el :system
   :id :example/system1
   :name "Example System"
   :desc "An example system to show how to model in overarch"
   :ct #{ ; set of children
         {:el :container
          :id :example/container1
          :name "Example Container"
          :tech "Java"
          :desc "Deployable application in the example system"}}}
...
}

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Modelling Methods

C4 Model: Architecture Model, Deployment Model, Dynamic Model UML: Use Case Model, Class Model, State Machines Concept Maps: Concept Model

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Architecture Model

Elements

:person :system :container :component :enterprise-boundary :context-boundary

Relations

:request :response :publish :subscribe :send :dataflow :rel

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Deployment Model

Elements

:node :system :container

Relations

:deployed-to :link :rel

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Class Model

Elements

:package :interface :class :field :method :enum :enum-value :stereotype :annotation :namespace :function :protocol

Relations

:inheritance :implementation :composition :aggregation :association :dependency

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Use Case Model

Elements

:use-case :actor :person :system :context-boundary

Relations

:uses :include :extends :generalizes

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State Machine

Elements

:state-machine :start-state :state :end-state :fork :join :choice :history-state :deep-history-state

Relations

:transition

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Concept Model

Elements

:concept :person :system :container :enterprise-boundary :context-boundary

Relations

:is-a :has :rel

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Artifact Generation

• template based
• reports
• project scaffolding
• code

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Model Queries

Element Selection by Criteria

• dynamic views

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Model Queries

Selection by Criteria

Criteria map: {:namespace "banking" :el container} Vector of maps: [{:namespace "banking" :el :container} {:namespace "banking" :el :request}]

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Views

Views define

• which model elements rendered
• how the model elements are rendered

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Rendering

PlantUML: C4 Views, UML Views Graphviz: Concept Maps Markdown: Glossary

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Export

JSON: complete model

Structurizr: architecture/deployment model and views only

EDN: (work in progress)

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Command Line Interface

Overarch CLI

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