SwiftPlantUML

Generate UML class diagrams from swift code with this Command Line Interface (CLI) and Swift Package.

Use one or more Swift files as input for a diagram to visualize class, struct, protocol, enum and extension types
with their instance and static members as well as their inheritance and implementation relationships

Usage

Command Line

Example to generate and render diagram, based on a single Swift file, in your browser:

swiftplantuml ./Tests/SwiftPlantUMLFrameworkTests/TestData/basics.txt

Run swiftplantuml in the directory containing the Swift files to be considered for diagram generation. Directories
will be searched recursively.

$ swiftplantuml classdiagram --help
OVERVIEW: Generate PlantUML script and view it and diagram in browser

USAGE: swift-plant-uml classdiagram [--config <config>] [--exclude <exclude> ...] [--output <format>] [--sdk <sdk>] [--verbose] [<paths> ...]

ARGUMENTS:
  <paths>                 List of paths to the files or directories containing
                          swift sources

OPTIONS:
  --config <config>       Path to custom configuration filed (otherwise will
                          search for `.swiftplantuml.yml` in current directory)
  --exclude <exclude>     paths to ignore source files. Takes precedence over
                          arguments
  --output <format>       Defines output format. Options: browser,
                          browserImageOnly, consoleOnly
  --sdk <sdk>             MacOSX SDK path used to handle type inference
                          resolution, usually `$(xcrun --show-sdk-path -sdk
                          macosx)`
  --verbose               Verbose
  --version               Show the version.
  -h, --help              Show help information.

As classdiagram is the default subcommand you can omit it.

Note: unknown type in diagrams for variables declared with type inference (e.g. var hasBasket = false) unless you specify sdk argument

In the following example the property hasBasket is of type Bool but the type is inferred and not explicitly declared.

class Bicycle: Vehicle {
    var hasBasket = false
}

SwiftPlantUML requires the macosx SDK in order to properly recognize the inferred type. If you have Xcode installed (which includes the macosx SDK) then use --sdk $(xcrun --show-sdk-path -sdk macosx).

Swift package

dependencies: [
    .package(url: "https://github.com/MarcoEidinger/SwiftPlantUML.git", .upToNextMajor(from: "0.5.0"))
]

This project is still in initial development. Generally this anything may change at any time and the public API should not be considered stable). However, I'll try to reserve breaking changes for new minor versions. You might feel more comfortable to pin the version to .upToNextMinor or even to an .exact version.

API documentation

Xcode source editor extension

See MarcoEidinger/SwiftPlantUML-Xcode-Extension for more details

Installation

Using Homebrew

brew install MarcoEidinger/formulae/swiftplantuml

Using Mint

$ mint install MarcoEidinger/SwiftPlantUML

Installing from source

You can also build and install from source by cloning this project and running
make install (Xcode 12 or later).

Manually
Run the following commands to build and install manually:

$ git clone https://github.com/MarcoEidinger/SwiftPlantUML.git
$ cd SwiftPlantUML
$ make install

Note: Working with Multiple Swift Versions

SwiftPlantUML hooks into SourceKit and therefore needs a Swift toolschain.

You should always run SwiftPlantUML with the same toolchain you use to compile your code.

You may want to override SwiftPlantUML's default Swift toolchain if you have multiple toolchains or Xcodes installed.

Here's the order in which SwiftPlantUML determines which Swift toolchain to use:

• $XCODE_DEFAULT_TOOLCHAIN_OVERRIDE
• $TOOLCHAIN_DIR or $TOOLCHAINS
• xcrun -find swift
• /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain
• /Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain
• ~/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain
• ~/Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain

sourcekitd.framework is expected to be found in the usr/lib/ subdirectory of the value passed in the paths above.

So if you encounter Fatal error: Loading sourcekitd.framework/Versions/A/sourcekitd failed then please check result of xcode-select -p to see if that directory subsequently contains a Swift toolschain. You can use sudo xcode-select -s <pathToYourXcodeInstallation> to rectify the situation, e.g.

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

Configuration

Configure SwiftPlantUML by adding a .swiftplantuml.yml file from the directory you'll run SwiftPlantUML from. Note: the same configuration options can be set programmatically with Configuration.

Options

You are able to

• include/exclude files (wildcards supported)
• include/exclude elements by name (wildcards supported)
• limit elements and members bases on their access level, e.g. show only public types
• hide extensions
• hide member access level attribute
• configure styles, use skin parameters and even include external files for theming (e.g. PUML Themes)
• exclude inheritance relationships based on parent (wildcards supported), e.g. do not show inheritance to Codable

Examples

Simple Example:

files:
    exclude:
    - "Tests/**/*.swift" # paths to ignore for diagram. Takes precedence over `included`.
elements:
  havingAccessLevel:
  - public
  - open
  showMembersWithAccessLevel:
  - public
  - open
  showExtensions: false
skinparamCommands: # see https://plantuml.com/skinparam
- skinparam classBackgroundColor PaleGreen
- skinparam classArrowColor SeaGreen
- skinparam classBorderColor SpringGreen
- skinparam stereotypeCBackgroundColor YellowGreen
- skinparam stereotypeCBackgroundColor<< Foo >> DimGray
relationships:
  inheritance:
    label: "inherits from"
    style:
      lineStyle: dotted
      lineColor: DarkViolet
      textColor: DarkViolet
    exclude:
    - "Codable"

Rich example: here

Code Completion during Editing

To get code completiong during editing use Visual Studio Code, the YAML extension created by Red Hat and the JSON schema for SwiftPlantUML.

In Visual Studio Code: Code -> Preferences -> Settings -> search for yaml

Click on Edit in settings.json and add the respective entry:

"yaml.schemas": {"https://raw.githubusercontent.com/MarcoEidinger/SwiftPlantUML/main/Configuration/Schema/json-schema-swiftplantuml.json": "/.swiftplantuml.yml" }

Large Diagrams

Online tools like PlantText do not support large diagrams. If your diagram image is incompletely rendered (or not visible at all) by PlantText in the browser then

• download PlantUML Java archive to your machine
• use swiftplantuml to generate the script and
• generate the actual image with plantuml locally

Here is the respective command (which assumes that plantuml.jar was downloaded in the current directory from which swifptlantuml runs)

swiftplantuml ./Sources/ --output consoleOnly > sources.txt | java -DPLANTUML_LIMIT_SIZE=8192 -jar plantuml.jar $1

This will result in the creation of sources.png file containing the class diagram up to the size limit.

PlantUML limits image width and height to 4096 with the option to override this limit (-DPLANTUML_LIMIT_SIZE) of which I made use in the command above.

In the table below you see the difference of class diagram output based on the same script. FYI: this script/diagram has 63 entities.

Planned improvements

• being able to render associations between elements
• being able to merge extensions with their known type

Known limitations

See Large Diagrams

Logging

CLI will log only error messages per default.

To log messages with lower priority (warning, info, debug) use the --verbose option.

Note: using --output consoleOnly, to print the PlantUML script in the console, will log any messages into a log file. This has the advantage that you can pipe the PlantUML script into a file without problems. You can tail the log file with tail -f /tmp/swiftplantuml.log

Acknowledgements

This project was inspired by https://github.com/palaniraja and its various predecessors. Out of personal preference I chose to start a new project. I wanted to provide a tool for Swift developers written in Swift! This will hopefully allow me and potential contributors to work on planned improvements faster and more efficient.

Last but not least a big shoutout to the great developers of PlantUML and the people who operate the related online servers / tools available on http://plantuml.com/ and https://www.planttext.com/

GitHub

https://github.com/MarcoEidinger/SwiftPlantUML