Levin

Browse, query, and manage Datalevin databases in VS Code

Levin (archaic English for "lightning") is a VS Code extension that provides a visual interface for Datalevin databases. It communicates directly with the dtlv CLI, requiring no REPL or Clojure setup.

Features

Database Explorer

• Open local databases via folder picker
• Connect to remote Datalevin servers with dtlv:// URIs
• Browse schema attributes with type information
• View entity counts by namespace
• Navigate database structure in the sidebar
• Auto-load recently opened databases

Query Editor

• Dedicated .dtlv.edn file support for Datalevin queries
• Syntax highlighting for Datalog queries
• Autocomplete for schema attributes and query keywords
• CodeLens for running queries directly from the editor
• Query history and saved queries

Results Panel

• Table view with sorting and pagination
• Tree view for nested/referenced data
• Raw EDN view
• Export to CSV, JSON, or EDN
• Click entity IDs to inspect

Entity Inspector

• View all attributes of an entity
• Navigate entity references
• Copy entity data as EDN

Schema Editor

• Add new schema attributes
• View existing schema with properties

Transaction Panel

• Stage and preview transactions
• Execute transact operations
• Validation before commit

Installation

1. Install the Levin Extension

From VS Code Marketplace (Recommended):

• Open VS Code
• Go to Extensions (Cmd+Shift+X / Ctrl+Shift+X)
• Search for "Levin"
• Click Install

Or from command line:

code --install-extension KwabenaBosompem.levin

2. Install Datalevin CLI

Levin requires the dtlv command-line tool to be installed and available in your PATH.

macOS

Using Homebrew (recommended):

brew install datalevin

Or download the binary:

# Download the latest release
curl -L https://github.com/juji-io/datalevin/releases/latest/download/dtlv-0.9.27-macos-amd64.zip -o dtlv.zip

# For Apple Silicon (M1/M2/M3):
curl -L https://github.com/juji-io/datalevin/releases/latest/download/dtlv-0.9.27-macos-aarch64.zip -o dtlv.zip

# Extract and install
unzip dtlv.zip
sudo mv dtlv /usr/local/bin/
chmod +x /usr/local/bin/dtlv

Linux

# Download the latest release (x64)
curl -L https://github.com/juji-io/datalevin/releases/latest/download/dtlv-0.9.27-linux-amd64.zip -o dtlv.zip

# For ARM64:
curl -L https://github.com/juji-io/datalevin/releases/latest/download/dtlv-0.9.27-linux-aarch64.zip -o dtlv.zip

# Extract and install
unzip dtlv.zip
sudo mv dtlv /usr/local/bin/
chmod +x /usr/local/bin/dtlv

Windows

1. Download the latest release from Datalevin releases
   • Choose dtlv-X.X.X-windows-amd64.zip
2. Extract dtlv.exe to a folder (e.g., C:\Program Files\Datalevin\)
3. Add that folder to your PATH:
   • Open System Properties → Environment Variables
   • Edit the Path variable and add C:\Program Files\Datalevin\
4. Restart VS Code

Verify Installation

dtlv --version
# Should output: Datalevin (version: X.X.X)

3. Configure (Optional)

If dtlv is not in your PATH, you can specify its location in VS Code settings:

{
  "levin.dtlvPath": "/path/to/dtlv"
}

Quick Start

1. Open the Levin sidebar (lightning bolt icon in the Activity Bar)
2. Click "Open Database..." or use Cmd+Alt+L O (Mac) / Ctrl+Alt+L O (Windows/Linux)
3. Choose "Datalog Database" or "Key-Value Store"
4. Select a local folder or enter a remote server URI
5. Start exploring!

Opening a Local Database

1. Click "Open Database" and select "Local Database"
2. Select a Datalevin database folder
3. The database will appear in the sidebar

Connecting to a Remote Server

1. Click "Open Database" and select "Remote Server"
2. Enter the server URI in the format: dtlv://username:password@host:port/database
   • Example: dtlv://datalevin:datalevin@192.168.1.113:8898/ontology
   • Without auth: dtlv://192.168.1.113:8898/test-db
3. The remote database will appear in the sidebar with a remote icon

Creating a New Database

1. Click "Create Database" in the sidebar or use Cmd+Alt+L C
2. Enter the database name
3. Select the parent folder
4. The new database is created and opened automatically

Commands

Query File Format

Create .dtlv.edn files for your queries:

;; Local database
{:db "/path/to/database"
 :query [:find ?e ?name ?email
         :where
         [?e :user/name ?name]
         [?e :user/email ?email]]
 :args []
 :limit 50}

;; Remote server
{:db "dtlv://username:password@host:port/database"
 :query [:find ?e ?name ?email
         :where
         [?e :user/name ?name]
         [?e :user/email ?email]]
 :args []
 :limit 50}

Configuration

{
  "levin.dtlvPath": "dtlv",
  "levin.queryHistorySize": 100,
  "levin.resultPageSize": 50,
  "levin.recentDatabases": []
}

Formatting .dtlv.edn Files

For formatting query files, install the cljfmt extension:

1. Install the cljfmt extension by pedrorgirardi
2. Add to your settings.json:

   {
     "files.associations": {
       "*.dtlv.edn": "clojure"
     },
     "[clojure]": {
       "editor.defaultFormatter": "pedrorgirardi.cljfmt",
       "editor.formatOnSave": true
     }
   }
   

Note: This changes .dtlv.edn files to Clojure mode, which removes the CodeLens "Run Query" button. You can still run queries with Ctrl+Enter or the Command Palette.

Development

# Clone and install
git clone https://github.com/kbosompem/levin
cd levin
npm install

# Compile
npm run compile

# Watch mode
npm run watch

# Run extension in debug mode
# Press F5 in VS Code

# Package
npm run package

Architecture

Levin uses a simple CLI-based architecture:

1. Direct CLI communication - All database operations execute through the dtlv command-line tool
2. No REPL required - No need for Clojure, Calva, or jack-in workflows
3. Local & Remote support - Works with local databases and remote Datalevin servers
4. Stateless - Each operation is independent

License

MIT License - see LICENSE for details.

Links

• Repository
• Issues
• Datalevin

Made with lightning by Kay Bosompem