moby/api
Sebastiaan van Stijn a3d4238b9c
Add "Warnings" to /info endpoint, and move detection to the daemon
When requesting information about the daemon's configuration through the `/info`
endpoint, missing features (or non-recommended settings) may have to be presented
to the user.

Detecting these situations, and printing warnings currently is handled by the
cli, which results in some complications:

- duplicated effort: each client has to re-implement detection and warnings.
- it's not possible to generate warnings for reasons outside of the information
  returned in the `/info` response.
- cli-side detection has to be updated for new conditions. This means that an
  older cli connecting to a new daemon may not print all warnings (due to
  it not detecting the new conditions)
- some warnings (in particular, warnings about storage-drivers) depend on
  driver-status (`DriverStatus`) information. The format of the information
  returned in this field is not part of the API specification and can change
  over time, resulting in cli-side detection no longer being functional.

This patch adds a new `Warnings` field to the `/info` response. This field is
to return warnings to be presented by the user.

Existing warnings that are currently handled by the CLI are copied to the daemon
as part of this patch; This change is backward-compatible with existing
clients; old client can continue to use the client-side warnings, whereas new
clients can skip client-side detection, and print warnings that are returned by
the daemon.

Example response with this patch applied;

```bash
curl --unix-socket /var/run/docker.sock http://localhost/info | jq .Warnings
```

```json
[
  "WARNING: bridge-nf-call-iptables is disabled",
  "WARNING: bridge-nf-call-ip6tables is disabled"
]
```

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2018-08-21 11:36:15 +02:00
..
server add optional fields in daemon.json to enable buildkit 2018-08-19 14:58:23 -07:00
templates/server Fix API template to not use "golang.org/x/net/context" 2018-07-13 09:54:24 +02:00
types Add "Warnings" to /info endpoint, and move detection to the daemon 2018-08-21 11:36:15 +02:00
common.go Bump API version to 1.39 2018-08-15 00:01:30 +00:00
common_unix.go Various code-cleanup 2018-05-23 17:50:54 +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 Add "Warnings" to /info endpoint, and move detection to the daemon 2018-08-21 11:36:15 +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.