moby/api
Albin Kerouanton 78479b1915
libnet: Make sure network names are unique
Fixes #18864, #20648, #33561, #40901.

[This GH comment][1] makes clear network name uniqueness has never been
enforced due to the eventually consistent nature of Classic Swarm
datastores:

> there is no guaranteed way to check for duplicates across a cluster of
> docker hosts.

And this is further confirmed by other comments made by @mrjana in that
same issue, eg. [this one][2]:

> we want to adopt a schema which can pave the way in the future for a
> completely decentralized cluster of docker hosts (if scalability is
> needed).

This decentralized model is what Classic Swarm was trying to be. It's
been superseded since then by Docker Swarm, which has a centralized
control plane.

To circumvent this drawback, the `NetworkCreate` endpoint accepts a
`CheckDuplicate` flag. However it's not perfectly reliable as it won't
catch concurrent requests.

Due to this design decision, API clients like Compose have to implement
workarounds to make sure names are really unique (eg.
docker/compose#9585). And the daemon itself has seen a string of issues
due to that decision, including some that aren't fixed to this day (for
instance moby/moby#40901):

> The problem is, that if you specify a network for a container using
> the ID, it will add that network to the container but it will then
> change it to reference the network by using the name.

To summarize, this "feature" is broken, has no practical use and is a
source of pain for Docker users and API consumers. So let's just remove
it for _all_ API versions.

[1]: https://github.com/moby/moby/issues/18864#issuecomment-167201414
[2]: https://github.com/moby/moby/issues/18864#issuecomment-167202589

Signed-off-by: Albin Kerouanton <albinker@gmail.com>
2023-09-12 10:40:13 +02:00
..
server Add otel support 2023-09-07 18:38:19 +00:00
templates/server swagger: fix "generated code" comment not in correct format 2019-11-05 11:32:37 -08:00
types libnet: Make sure network names are unique 2023-09-12 10:40:13 +02:00
common.go API: bump version to 1.44 2023-05-06 01:41:49 +02:00
common_unix.go remove pre-go1.17 build-tags 2023-05-19 20:38:51 +02:00
common_windows.go Add canonical import comment 2018-02-05 16:51:57 -05:00
README.md API: minor fixes in the README 2017-10-11 16:12:10 +02:00
swagger-gen.yaml Use a config to generate swagger api types 2016-10-31 11:13:41 -04:00
swagger.yaml libnet: Make sure network names are unique 2023-09-12 10:40:13 +02:00

Working on the Engine API

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.yaml A 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:

  1. Automatically generate documentation.
  2. Automatically generate the Go server and client. (A work-in-progress.)
  3. Provide a machine readable version of the API for introspecting what it can do, automatically generating clients for other languages, etc.

Updating the API documentation

The API documentation is generated entirely from api/swagger.yaml. If you make updates to the API, 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 definitions section.

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 when making edits to ensure you are doing the right thing.

Viewing the API documentation

When you make edits to swagger.yaml, you may want to check the generated API documentation to ensure it renders correctly.

Run make swagger-docs and a preview will be running at http://localhost. Some of the styling may be incorrect, but you'll be able to ensure that it is generating the correct documentation.

The production documentation is generated by vendoring swagger.yaml into docker/docker.github.io.