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Project Structure

When you initialize a DBOS project with npx @dbos-inc/create, it has the following structure:

dbos-hello-app/
├── README.md
├── dbos-config.yaml
├── eslint.config.js
├── jest.config.js
├── knexfile.js
├── migrations/
├── node_modules/
├── package.json
├── package-lock.json
├── src/
│   |── operations.ts
│   └── operations.test.ts
├── start_postgres_docker.js
└── tsconfig.json

The two most important files in a DBOS project are dbos-config.yaml and src/operations.ts.

dbos-config.yaml defines the configuration of a DBOS project, including database connection information, migration configuration, and global logging configuration. All options are documented in our configuration reference.

src/operations.ts is the entrypoint, where DBOS looks for your code. At startup, the DBOS runtime automatically loads all classes that are exported or (directly and indirectly) referenced from this file, serving their endpoints and registering their decorated functions. More precisely, DBOS assumes your compiled code is exported from dist/operations.js, the default location to which src/operations.ts is compiled. If you're writing a small application, you can write all your code directly in this file. In a larger application, you can write your code wherever you want, but should use src/operations.ts as an index file, exporting code written elsewhere:

// Placed in operations.ts:
export { OperationClass1, OperationClass2 } from './FileA';
export { OperationClass3 } from './operations/FileB';

It is not necessary to export classes that are already referenced by the entrypoint file(s), as these will be loaded and decorated methods will be registered. You can also define multiple entrypoint files using the runtimeConfig section of the configuration.

As for the rest of the directory:

  • src/operations.test.ts contains example unit tests written with Jest and our testing runtime. jest.config.js contains Jest configuration.
  • knexfile.js is a configuration file for Knex, which we use as a query builder and migration tool.
  • migrations is initialized with a Knex database migration used in the quickstart guide. You can replace this with your own migration files.
  • node_modules, package.json, package-lock.json, and tsconfig.json are needed by all Node/Typescript projects. eslint.config.js is used by the JavaScript/TypeScript linter, ESLint.
  • start_postgres_docker.js is a convenience script that initializes a Docker Postgres container for use in the quickstart. You can modify this script if you want to use Docker-hosted Postgres for local development.