plantuml-sequence

Create PlantUML sequence diagrams programmatically from Python.

The basic example of the PlantUML Documentation can be implemented with the following Python script:

from plantuml_sequence import Diagram

with open("my-diagram.puml", "w") as file, Diagram(file) as sequence:
    (
        sequence.message("Alice", "Bob", "Authentication Request")
        .message("Bob", "Alice", "Authentication Response", arrow_style="-->")
        .blank_line()
        .message("Alice", "Bob", "Another authentication Request")
        .message("Alice", "Bob", "Another authentication Response", arrow_style="<--")
    )

Its output inside my-diagram.puml is:

@startuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response

Alice -> Bob: Another authentication Request
Alice <-- Bob: Another authentication Response
@enduml

This file be compiled to an image using the plantuml command-line or a online server. See the PlantUML documentation for more details.

Read the documentation on ReadTheDocs!

Installation and supported Python versions

pip install plantuml-sequence

Python 3.10+ is supported

Supported PlantUML features

Not all of the features of message sequence charts are supported yet. See the list of implemented features below.

General

• Use teoz renderer

Participants

• Declaring participants
• Multiline participants
• Create participant with message
• Lifeline activation / deactivation
• Lifeline auto-activate
• Participants encompass (Box around participants)
• Remove foot boxes

Messages

• Messages
• Basic autonumber message numbering
• Advanced auto numbering
  • autonumber formats
  • autonumber sequence increments
• Hide unlinked participants
• Mainframe

Notes

• Different note shapes (note, hnote, rnote)
• Notes on messages
• Notes over / left / right of lifelines
• Notes across all participants
• Multiple notes at the same level

Flow

• Basic message grouping
• alt / else groups
• Divider
• Reference
• Delay
• Space

Styling

• Colored groups
• Arrow style change
  • Standard arrow styles
  • Short arrows
• Slanted arrows
• Styling changes using the skinparam command

Preprocessing

Currently no preprocessing features are planned to be supported

• Variable definition
• Boolean expression
• Conditions
• While loops
• Procedures & functions blocks
• Include directive
• Memory dump
• Assertions