PlantUML Integrator

An Obsidian plugin that renders PlantUML diagrams and is ready for Community Plugins publication.

Features

• Render PlantUML code blocks (plantuml, puml) in Markdown preview.
• Render .puml embedded files.
• Cache include dependency trees and auto re-render when included files are modified.
• Right-click each rendered diagram to clear cache and re-render only that diagram.
• Select rendering mode: remote server endpoint or local PlantUML server.

Code block rendering image

Render Modes

Server mode (default)

Uses a remote PlantUML-compatible HTTP endpoint (e.g. kroki.io). Configure PlantUML server URL in settings (default: https://kroki.io/plantuml/svg).

Local jar mode

Runs a local PlantUML PicoWeb server and sends requests to it. This mode does not invoke java directly from the plugin; you must start the server yourself.

Why? Due to platform security constraints, Obsidian plugins cannot spawn external processes. Instead, the plugin communicates with a running PlantUML server via HTTP.

Starting the local server:

java -jar "<path-to-plantuml.jar>" -picoweb

The server listens on port 8080 by default.

Start the local server automatically at user login:

You can register the PlantUML PicoWeb command as a per-user startup entry so it is launched when you sign in.

Windows (HKCU Run):

$runKey = 'Registry::HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run'
$javaCommand = 'javaw.exe'
$javaExe = (Get-Command $javaCommand -ErrorAction SilentlyContinue | Select-Object -First 1 -ExpandProperty Source)
if (-not $javaExe) { $javaExe = $javaCommand }
$jarPath = 'C:\path\to\plantuml.jar'
$command = '"' + $javaExe + '" -jar "' + $jarPath + '" -picoweb'
New-Item -Path $runKey -Force | Out-Null
Set-ItemProperty -Path $runKey -Name 'PlantUML PicoWeb' -Value $command

macOS (LaunchAgent):

mkdir -p ~/Library/LaunchAgents
cat > ~/Library/LaunchAgents/com.user.plantuml.picoweb.plist <<'EOF'
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
   <dict>
      <key>Label</key>
      <string>com.user.plantuml.picoweb</string>
      <key>ProgramArguments</key>
      <array>
         <string>/usr/bin/java</string>
         <string>-jar</string>
         <string>/path/to/plantuml.jar</string>
         <string>-picoweb</string>
      </array>
      <key>RunAtLoad</key>
      <true/>
      <key>KeepAlive</key>
      <true/>
   </dict>
</plist>
EOF
launchctl load ~/Library/LaunchAgents/com.user.plantuml.picoweb.plist

Linux (systemd user service):

mkdir -p ~/.config/systemd/user
cat > ~/.config/systemd/user/plantuml-picoweb.service <<'EOF'
[Unit]
Description=PlantUML PicoWeb server

[Service]
ExecStart=/usr/bin/java -jar /path/to/plantuml.jar -picoweb
Restart=on-failure

[Install]
WantedBy=default.target
EOF
systemctl --user daemon-reload
systemctl --user enable --now plantuml-picoweb.service

Check whether the login startup registration is active:

Windows:

(Get-ItemProperty -Path 'Registry::HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run' -Name 'PlantUML PicoWeb').'PlantUML PicoWeb'

macOS:

launchctl list | grep com.user.plantuml.picoweb

Linux:

systemctl --user status plantuml-picoweb.service

Remove the login startup registration:

Windows:

Remove-ItemProperty -Path 'Registry::HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run' -Name 'PlantUML PicoWeb'

macOS:

launchctl unload ~/Library/LaunchAgents/com.user.plantuml.picoweb.plist
rm ~/Library/LaunchAgents/com.user.plantuml.picoweb.plist

Linux:

systemctl --user disable --now plantuml-picoweb.service
rm ~/.config/systemd/user/plantuml-picoweb.service
systemctl --user daemon-reload

Replace the Java executable and JAR path with values that match your environment.

Plugin settings:

Settings screen image

Convenience feature: Right-click any rendered diagram and select Copy local server start command to copy the javaw.exe -jar ... command to the clipboard.

If the server is not running, the plugin shows the start command in the error message.

Build

1. Install dependencies:

   npm install
   

2. Build:

   npm run build
   

Development

Watch mode:

npm run dev

Copy manifest.json, main.js, and styles.css to your Obsidian vault plugin folder.

Lint

Run lint checks:

npm run lint

Run lint checks with auto-fix:

npm run lint:fix

npm run lint:fix only applies ESLint auto-fixes and does not update version files.

Community Plugin Release

1. Verify manifest.json fields: id, name, author, description, and version.
2. Run npm run lint:fix.
3. Run npm run lint.
4. Run npm run version:patch for fix releases. This command updates package.json, package-lock.json, manifest.json, and versions.json together.
5. Run npm run build to generate main.js.
6. Create a GitHub Release with the same tag as the manifest.json version (for example, 0.1.0).
7. Attach the following 3 files as release assets:
   • manifest.json
   • main.js
   • styles.css
8. Submit a registration PR to the Obsidian community plugin list repository.

GitHub Actions (Release ZIP)

• Workflow file: .github/workflows/release-zip.yml
• Trigger (manual): workflow_dispatch
• Trigger (automatic): release.published
• Output ZIP: ${id}-${version}.zip containing manifest.json, main.js, styles.css, and versions.json
• Output destination: uploaded as a workflow artifact
• Release behavior: automatically attached to the GitHub Release when triggered by release publish

Version Bump Checklist

1. Run npm run version:patch
2. Verify the updated version in manifest.json and versions.json
3. npm run build
4. Create a git tag and GitHub Release

Support the Project

If you find this plugin helpful, consider sponsoring the project: