Env Vars

dg list envs

# .env (at project root, never commit to git)
DATABASE_URL=postgresql://localhost:5432/mydb
API_KEY=secret_key_here
SNOWFLAKE_ACCOUNT=myaccount
SNOWFLAKE_USER=myuser
SNOWFLAKE_PASSWORD=secret

import dagster as dg


class DatabaseResource(dg.ConfigurableResource):
    connection_string: str = dg.EnvVar("DATABASE_URL")
    timeout: int = dg.EnvVar.int("DB_TIMEOUT")


# Dagster automatically loads DATABASE_URL and DB_TIMEOUT from .env

# defs/my_component/defs.yaml
component: dagster_sling.SlingReplicationComponent

params:
  sling:
    connections:
      - name: MY_POSTGRES
        type: postgres
        host: "{{ env.DB_HOST }}"
        port: "{{ env.DB_PORT }}"
        database: "{{ env.DB_NAME }}"

my_project/
├── .env              # Local development (gitignored)
├── .env.example      # Template (committed to git)
├── .env.staging      # Staging config (gitignored)
└── .env.prod         # Production config (gitignored)

# .env.example (committed to git)
DATABASE_URL=postgresql://localhost:5432/mydb
API_KEY=your_api_key_here
SNOWFLAKE_ACCOUNT=your_account
SNOWFLAKE_USER=your_user
SNOWFLAKE_PASSWORD=your_password

# Development (uses .env by default)
dg dev

# Staging
dg launch --env-file .env.staging --assets my_asset

# Production
dg launch --env-file .env.prod --assets my_asset