Add a specific config for the update command

This allows to define clearly what is mutable or not in a container
and remove the use of the internal HostConfig struct to be used.

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

api/server/router/container/container_routes.go

@@ -1,6 +1,7 @@
 package container
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
@@ -332,11 +333,17 @@ func (s *containerRouter) postContainerUpdate(ctx context.Context, w http.Respon
 		return err
 	}
 
-	_, hostConfig, _, err := runconfig.DecodeContainerConfig(r.Body)
-	if err != nil {
+	var updateConfig container.UpdateConfig
+
+	decoder := json.NewDecoder(r.Body)
+	if err := decoder.Decode(&updateConfig); err != nil {
 		return err
 	}
 
+	hostConfig := &container.HostConfig{
+		Resources: updateConfig.Resources,
+	}
+
 	name := vars["name"]
 	warnings, err := s.backend.ContainerUpdate(name, hostConfig)
 	if err != nil {

docs/reference/api/docker_remote_api.md

@@ -95,6 +95,7 @@ This section lists each version from latest to oldest.  Each listing includes a
 
 [Docker Remote API v1.22](docker_remote_api_v1.22.md) documentation
 
+* `POST /container/(name)/update` updates the resources of a container.
 * `GET /containers/json` supports filter `isolation` on Windows.
 * `GET /containers/json` now returns the list of networks of containers.
 * `GET /info` Now returns `Architecture` and `OSType` fields, providing information
@@ -120,7 +121,7 @@ This section lists each version from latest to oldest.  Each listing includes a
 * `GET /volumes` lists volumes from all volume drivers.
 * `POST /volumes/create` to create a volume.
 * `GET /volumes/(name)` get low-level information about a volume.
-* `DELETE /volumes/(name)`remove a volume with the specified name.
+* `DELETE /volumes/(name)` remove a volume with the specified name.
 * `VolumeDriver` was moved from `config` to `HostConfig` to make the configuration portable.
 * `GET /images/(name)/json` now returns information about an image's `RepoTags` and `RepoDigests`.
 * The `config` option now accepts the field `StopSignal`, which specifies the signal to use to kill a container.

docs/reference/api/docker_remote_api_v1.22.md

@@ -1023,7 +1023,7 @@ Update resource configs of one or more containers.
        Content-Type: application/json
 
        {
-           "HostConfig": {
+           "UpdateConfig": {
                "Resources": {
                    "BlkioWeight": 300,
                    "CpuShares": 512,