compose/api/backend/backend.go

120 lines
3.0 KiB
Go

/*
Copyright 2020 Docker Compose CLI authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package backend
import (
"errors"
"fmt"
"github.com/sirupsen/logrus"
"github.com/docker/compose-cli/api/cloud"
"github.com/docker/compose-cli/api/compose"
"github.com/docker/compose-cli/api/containers"
"github.com/docker/compose-cli/api/errdefs"
"github.com/docker/compose-cli/api/resources"
"github.com/docker/compose-cli/api/secrets"
"github.com/docker/compose-cli/api/volumes"
)
var (
errNoType = errors.New("backend: no type")
errNoName = errors.New("backend: no name")
errTypeRegistered = errors.New("backend: already registered")
)
type initFunc func() (Service, error)
type getCloudServiceFunc func() (cloud.Service, error)
type registeredBackend struct {
name string
backendType string
init initFunc
getCloudService getCloudServiceFunc
}
var backends = struct {
r []*registeredBackend
}{}
var instance Service
// Current return the active backend instance
func Current() Service {
return instance
}
// WithBackend set the active backend instance
func WithBackend(s Service) {
instance = s
}
// Service aggregates the service interfaces
type Service interface {
ContainerService() containers.Service
ComposeService() compose.Service
ResourceService() resources.Service
SecretsService() secrets.Service
VolumeService() volumes.Service
}
// Register adds a typed backend to the registry
func Register(name string, backendType string, init initFunc, getCoudService getCloudServiceFunc) {
if name == "" {
logrus.Fatal(errNoName)
}
if backendType == "" {
logrus.Fatal(errNoType)
}
for _, b := range backends.r {
if b.backendType == backendType {
logrus.Fatal(errTypeRegistered)
}
}
backends.r = append(backends.r, &registeredBackend{
name,
backendType,
init,
getCoudService,
})
}
// Get returns the backend registered for a particular type, it returns
// an error if there is no registered backends for the given type.
func Get(backendType string) (Service, error) {
for _, b := range backends.r {
if b.backendType == backendType {
return b.init()
}
}
return nil, errdefs.ErrNotFound
}
// GetCloudService returns the backend registered for a particular type, it returns
// an error if there is no registered backends for the given type.
func GetCloudService(backendType string) (cloud.Service, error) {
for _, b := range backends.r {
if b.backendType == backendType {
return b.getCloudService()
}
}
return nil, fmt.Errorf("backend not found for backend type %s", backendType)
}