Fountainedge is a simple workflow engine written in Elixir that roughly models forks and joins as described in the paper, Process Modeling Notations and Workflow Patterns by Stephen A. White, IBM Corporation. Uses Graphviz for graphical representations as UML Activity Diagrams.
Execution of tasks is not supported; however, such functionality could be built on top.
The workflow is modelled as graphs consisting of nodes and edges. Parallel forks and joins are tracked using tokens.
Define a schema:
alias Fountainedge.{Workflow, Schema, Node, Edge}
schema = %Schema{
nodes: [
%Node{id: 100, type: :initial},
%Node{id: 1, label: "Decision"},
%Node{id: 2, label: "Choice 1"},
%Node{id: 3, label: "Choice 2"},
%Node{id: 4, label: "Before Forking"},
%Node{id: 5, type: :fork, join: 9},
%Node{id: 6, label: "Parallel 1.1"},
%Node{id: 7, label: "Parallel 1.2"},
%Node{id: 8, label: "Parallel 2"},
%Node{id: 9, type: :join},
%Node{id: 10, label: "After Joining"},
%Node{id: 11, type: :final},
],
edges: [
%Edge{id: 100, next: 1},
%Edge{id: 1, next: 2, attributes: [label: "Y"]},
%Edge{id: 1, next: 3, attributes: [label: "N"]},
%Edge{id: 2, next: 4},
%Edge{id: 3, next: 4},
%Edge{id: 4, next: 5},
%Edge{id: 5, next: 6},
%Edge{id: 5, next: 8},
%Edge{id: 6, next: 7},
%Edge{id: 7, next: 6},
%Edge{id: 7, next: 9},
%Edge{id: 8, next: 9},
%Edge{id: 9, next: 10},
%Edge{id: 10, next: 11},
],
} Initialise the workflow:
workflow = Workflow.initialize(schema)Get a list of valid out edges:
Fountainedge.out_edges(workflow)
# [%Edge{id: 1, next: 2}]Transition along an out edge:
workflow = Fountainedge.transition(workflow, %Edge{id: 1, next: 2})Graphing:
Fountainedge.Graph.graph(workflow)
|> Graphvix.Graph.compile(filename, :svg)This package can be installed by adding fountainedge to your list of dependencies in mix.exs:
def deps do
[
{:fountainedge, "~> 1.0.0"}
]
end2019 (c) Damien Bezborodov
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