The Engine API is an HTTP API used by the command-line client to communicate with the daemon. It can also be used by third-party software to control the daemon.
It consists of various components in this repository:
api/swagger.yamlA Swagger definition of the API.
api/types/Types shared by both the client and server, representing various objects, options, responses, etc. Most are written manually, but some are automatically generated from the Swagger definition. See #27919 for progress on this.
cli/The command-line client.
client/The Go client used by the command-line client. It can also be used by third-party Go programs.
daemon/The daemon, which serves the API.
## Swagger definition
The API is defined by the Swagger definition in
api/swagger.yaml. This definition can be used to:
The API documentation is generated entirely from
api/swagger.yaml. If you make updates to the API, you'll need to edit this file to represent the change in the documentation.
The file is split into two main sections:
definitions, which defines re-usable objects used in requests and responses
paths, which defines the API endpoints (and some inline objects which don't need to be reusable)
To make an edit, first look for the endpoint you want to edit under
paths, then make the required edits. Endpoints may reference reusable objects with
$ref, which can be found in the
There is hopefully enough example material in the file for you to copy a similar pattern from elsewhere in the file (e.g. adding new fields or endpoints), but for the full reference, see the Swagger specification
swagger.yaml is validated by
hack/validate/swagger to ensure it is a valid Swagger definition. This is useful for when you are making edits to ensure you are doing the right thing.
When you make edits to
swagger.yaml, you may want to check the generated API documentation to ensure it renders correctly.
All the documentation generation is done in the documentation repository, docker/docker.github.io. The Swagger definition is vendored periodically into this repository, but you can manually copy over the Swagger definition to test changes.
api/swagger.yaml in this repository to
engine/api/[VERSION_NUMBER]/swagger.yaml in the documentation repository, overwriting what is already there. Then, run
docker-compose up in the documentation repository and browse to http://localhost:4000/engine/api/ when it finishes rendering.