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Publisher Connections

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Configure database connections for Malloy Publisher deployments. For an overview of supported databases, see Database Support.

Configuration File

Publisher uses publisher.config.json for database connections. This file lives in your server root directory.

Important: Publisher does not support environment variable substitution. Put actual credential values directly in the config file.

Basic Structure 

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "connection_name": {
          "type": "backend_type",
          ...connection options...
        }
      },
      "packages": [
        {
          "name": "my-package",
          "location": "./my-package"
        }
      ]
    }
  ]
}

DuckDB

DuckDB can read data files bundled in your published package:

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "duckdb": {
          "type": "duckdb",
          "workingDirectory": "./data"
        }
      },
      "packages": [
        {
          "name": "my-analytics",
          "location": "./my-analytics"
        }
      ]
    }
  ]
}

The workingDirectory sets the base path for file references. If your Malloy code references 'flights.parquet', it will look in the ./data directory.

MotherDuck 

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "md": {
          "type": "motherduck",
          "token": "your_motherduck_token_here",
          "database": "my_database"
        }
      },
      "packages": [...]
    }
  ]
}

BigQuery

With service account (recommended for production):

Embed the service account JSON directly in the config:

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "bigquery": {
          "type": "bigquery",
          "defaultProjectId": "my-gcp-project",
          "location": "US",
          "serviceAccountKeyJson": "{\n  \"type\": \"service_account\",\n  \"project_id\": \"my-gcp-project\",\n  \"private_key_id\": \"abc123def456\",\n  \"private_key\": \"-----BEGIN PRIVATE KEY-----\\nMIIEvgIBAD...your-key-here...\\n-----END PRIVATE KEY-----\\n\",\n  \"client_email\": \"malloy-publisher@my-gcp-project.iam.gserviceaccount.com\",\n  \"client_id\": \"123456789\",\n  \"auth_uri\": \"https://accounts.google.com/o/oauth2/auth\",\n  \"token_uri\": \"https://oauth2.googleapis.com/token\",\n  \"auth_provider_x509_cert_url\": \"https://www.googleapis.com/oauth2/v1/certs\",\n  \"client_x509_cert_url\": \"https://www.googleapis.com/robot/v1/metadata/x509/malloy-publisher%40my-gcp-project.iam.gserviceaccount.com\",\n  \"universe_domain\": \"googleapis.com\"\n}"
        }
      },
      "packages": [...]
    }
  ]
}

With gcloud auth (development only):

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "bigquery": {
          "type": "bigquery",
          "defaultProjectId": "my-gcp-project",
          "location": "US"
        }
      },
      "packages": [...]
    }
  ]
}

Snowflake

Password authentication:

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "snowflake": {
          "type": "snowflake",
          "account": "myorg-myaccount",
          "username": "publisher_user",
          "password": "your_password_here",
          "warehouse": "compute_wh",
          "database": "analytics",
          "schema": "public"
        }
      },
      "packages": [...]
    }
  ]
}

RSA private key authentication:

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "snowflake": {
          "type": "snowflake",
          "account": "myorg-myaccount",
          "username": "publisher_user",
          "privateKey": "-----BEGIN PRIVATE KEY-----\nMIIEvgIBAD...your-key-here...\n-----END PRIVATE KEY-----",
          "privateKeyPassphrase": "your_passphrase_if_encrypted",
          "warehouse": "compute_wh",
          "database": "analytics"
        }
      },
      "packages": [...]
    }
  ]
}

PostgreSQL 

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "postgres": {
          "type": "postgres",
          "host": "db.example.com",
          "port": 5432,
          "database": "analytics",
          "username": "publisher_readonly",
          "password": "your_password_here"
        }
      },
      "packages": [...]
    }
  ]
}

MySQL 

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "mysql": {
          "type": "mysql",
          "host": "db.example.com",
          "port": 3306,
          "database": "analytics",
          "user": "publisher_readonly",
          "password": "your_password_here"
        }
      },
      "packages": [...]
    }
  ]
}

Trino and Presto 

{
  "projects": [
    {
      "name": "default",
      "connections": {
        "trino": {
          "type": "trino",
          "server": "https://trino.example.com",
          "port": 8443
        }
      },
      "packages": [...]
    }
  ]
}

For Presto, use "type": "presto" with the same configuration options.

Multi-Environment Configuration

You can configure multiple projects for different environments:

{
  "projects": [
    {
      "name": "staging",
      "connections": {
        "postgres": {
          "type": "postgres",
          "host": "staging-db.example.com",
          "port": 5432,
          "database": "analytics",
          "username": "staging_user",
          "password": "staging_password"
        }
      },
      "packages": [
        {
          "name": "analytics",
          "location": "./packages/analytics"
        }
      ]
    },
    {
      "name": "production",
      "connections": {
        "postgres": {
          "type": "postgres",
          "host": "prod-db.example.com",
          "port": 5432,
          "database": "analytics",
          "username": "prod_readonly",
          "password": "prod_password"
        }
      },
      "packages": [
        {
          "name": "analytics",
          "location": "./packages/analytics"
        }
      ]
    }
  ]
}

Next Steps