Malloy Documentation
search
previousThe Tao of Malloy
Database Supportnext

VS Code Extension

VSCode document

The Malloy VS Code Extension is the primary authoring environment for Malloy models. It includes schema browsing, query execution, language auto-complete, documentation, and result visualizations.

Installation

  1. Download Visual Studio Code: If you don't already have it, download Visual Studio Code

  2. Open the Extensions panel: Press Cmd+Shift+X (Mac) or Ctrl+Shift+X (Windows/Linux). Or open the Command Palette (Cmd+Shift+P / Ctrl+Shift+P) and type "Extensions: Install Extensions"

  3. Install Malloy: Search for "Malloy" and click Install

    Or install directly from the VS Code Marketplace.

  4. Try the samples: Clone the malloy-samples repository:

    Option A: In VS Code, use Clone Git Repository from the Start screen and enter:

    https://github.com/malloydata/malloy-samples.git

    Option B: From the command line:

    git clone https://github.com/malloydata/malloy-samples.git
cd malloy-samples
code .

    DuckDB is built into the extension, so you can run queries immediately—try opening any .malloy file in the faa or ecommerce folders.

VS Code Web (github.dev)

The Malloy Extension also works in VS Code Web environments like github.dev. Press . on any GitHub repository page to open it in the browser-based editor, then install the Malloy extension.

Limitation: VS Code Web only supports DuckDB with local files (CSV, JSON, Parquet). For BigQuery, Snowflake, or PostgreSQL, use VS Code Desktop.

Configuring Connections

Configure database connections through the VS Code command palette.

Adding Connections

  1. Open Command Palette: Cmd+Shift+P (Mac) or Ctrl+Shift+P (Windows/Linux)

  2. Type: Malloy: Edit Connections

  3. Click Add Connection and select your database type

  4. Fill in the connection details

Where Connections Are Stored

VS Code stores Malloy connections in your user settings:

Mac: ~/Library/Application Support/Code/User/settings.json Windows: %APPDATA%\Code\User\settings.json Linux: ~/.config/Code/User/settings.json

Example settings.json with Malloy connections:

{
  "malloy.connections": [
    {
      "name": "duckdb",
      "backend": "duckdb",
      "id": "duckdb-default"
    },
    {
      "name": "md",
      "backend": "duckdb",
      "id": "motherduck-default",
      "databasePath": "md:"
    },
    {
      "name": "bigquery",
      "backend": "bigquery",
      "id": "bigquery-default",
      "projectId": "my-gcp-project"
    },
    {
      "name": "bq_service_account",
      "backend": "bigquery",
      "id": "bq-sa-connection",
      "serviceAccountKeyPath": "/path/to/service-account-key.json",
      "configKey": "serviceAccountKeyPath"
    },
    {
      "name": "postgres",
      "backend": "postgres",
      "id": "postgres-default",
      "host": "localhost",
      "port": 5432,
      "databaseName": "analytics",
      "username": "analyst"
    },
    {
      "name": "snowflake",
      "backend": "snowflake",
      "id": "snowflake-default",
      "account": "myorg-myaccount",
      "username": "analyst",
      "warehouse": "compute_wh",
      "database": "analytics"
    }
  ]
}

Environment Variable Configuration

Some databases support configuration via environment variables. Set these before launching VS Code.

MotherDuck

MotherDuck is configured through a token. In MotherDuck, click Settings then copy your token.

export MOTHERDUCK_TOKEN=your_token_here

Then launch VS Code. The extension will automatically use the token when connecting to MotherDuck databases.

Example usage:

source: hacker_news is md.table('sample_data.hn.hacker_news')

The default connection name for MotherDuck is md.

MySQL

MySQL connections are configured only through environment variables. There is no UI configuration for MySQL in VS Code.

export MYSQL_USER=readonly
export MYSQL_HOST=db.example.com
export MYSQL_PORT=3306
export MYSQL_PASSWORD=your_password
export MYSQL_DATABASE=analytics

Then launch VS Code. The default connection name is mysql.

Note: MYSQL_USER is required. Other variables are optional but typically needed.

Snowflake

Snowflake can be configured via UI or environment variables:

export SNOWFLAKE_ACCOUNT=myorg-myaccount   # Required
export SNOWFLAKE_USER=analyst
export SNOWFLAKE_PASSWORD=your_password
export SNOWFLAKE_WAREHOUSE=compute_wh
export SNOWFLAKE_DATABASE=analytics
export SNOWFLAKE_SCHEMA=public

Snowflake also supports TOML configuration at ~/.snowflake/connections.toml. See Snowflake connection configuration for details.

Trino 

export TRINO_SERVER=https://trino.example.com   # Required
export TRINO_USER=analyst                        # Required
export TRINO_PASSWORD=your_password
export TRINO_CATALOG=hive
export TRINO_SCHEMA=default

The default connection name is trino.

Presto 

export PRESTO_HOST=presto.example.com   # Required
export PRESTO_PORT=8080                 # Defaults to 8080
export PRESTO_USER=analyst
export PRESTO_PASSWORD=your_password
export PRESTO_CATALOG=hive
export PRESTO_SCHEMA=default

The default connection name is presto.

Databases Without Environment Variable Support

  • BigQuery: Uses gcloud auth login --update-adc (OAuth) or service account key file

  • PostgreSQL: Uses connection configuration in VS Code UI (credentials stored in system keychain)

  • DuckDB: Uses file paths directly, no authentication needed

Database-Specific Setup

DuckDB

DuckDB runs locally with zero configuration. It reads Parquet, CSV, and JSON files.

// Local files (relative to .malloy file)
source: flights is duckdb.table('data/flights.parquet')
source: users is duckdb.table('../users.csv')

// URLs
source: remote_data is duckdb.table('https://example.com/data.parquet')

MotherDuck

Set your token as an environment variable before launching VS Code:

export MOTHERDUCK_TOKEN=your_token_here

Or configure via Malloy: Edit Connections with databasePath set to md:.

BigQuery

OAuth (recommended for development):

gcloud auth login --update-adc
gcloud config set project my-project-id --installation

Then add a BigQuery connection via Malloy: Edit Connections. Leave the service account field empty to use gcloud credentials.

Service account:

In Malloy: Edit Connections, click "Pick file" to select your service account JSON key.

Snowflake

Both password and RSA key authentication are supported via Malloy: Edit Connections.

You can also use Snowflake's connections.toml file:

Location: ~/.snowflake/connections.toml

[default]
account = "myorg-myaccount"
user = "analyst"
password = "your_password"
warehouse = "compute_wh"
database = "analytics"
schema = "public"

PostgreSQL

Add a PostgreSQL connection via Malloy: Edit Connections. Enter host, port, database, username, and password. The password is stored securely in your system keychain.

MySQL

MySQL connections require environment variables (see above). The extension will detect the connection automatically when the variables are set.

Trino and Presto

Add a Trino or Presto connection via Malloy: Edit Connections. Enter the server URL and port.

Next Steps