1
0
Fork 0
mirror of https://github.com/moby/moby.git synced 2022-11-09 12:21:53 -05:00
moby--moby/graphdriver/driver.go
Alexander Larsson 5d76681c3d Implement fallback for getting the size of a container
This moves Driver.Size() to Differ.DiffSize(), removing the empty
implementations in devmapper and dummy, and renaming the one in aufs.

Then we fall back to a container.Changes() implementation in the non-aufs
case.
2013-11-19 10:36:54 +01:00

90 lines
1.9 KiB
Go

package graphdriver
import (
"fmt"
"github.com/dotcloud/docker/archive"
"github.com/dotcloud/docker/utils"
"os"
"path"
)
type InitFunc func(root string) (Driver, error)
type Driver interface {
String() string
Create(id, parent string) error
Remove(id string) error
Get(id string) (dir string, err error)
Status() [][2]string
Cleanup() error
}
type Differ interface {
Diff(id string) (archive.Archive, error)
Changes(id string) ([]archive.Change, error)
ApplyDiff(id string, diff archive.Archive) error
DiffSize(id string) (bytes int64, err error)
}
var (
// All registred drivers
drivers map[string]InitFunc
// Slice of drivers that should be used in an order
priority = []string{
"aufs",
"devicemapper",
"dummy",
}
)
func init() {
drivers = make(map[string]InitFunc)
}
func Register(name string, initFunc InitFunc) error {
if _, exists := drivers[name]; exists {
return fmt.Errorf("Name already registered %s", name)
}
drivers[name] = initFunc
return nil
}
func GetDriver(name, home string) (Driver, error) {
if initFunc, exists := drivers[name]; exists {
return initFunc(path.Join(home, name))
}
return nil, fmt.Errorf("No such driver: %s", name)
}
func New(root string) (Driver, error) {
var driver Driver
var lastError error
// Use environment variable DOCKER_DRIVER to force a choice of driver
if name := os.Getenv("DOCKER_DRIVER"); name != "" {
return GetDriver(name, root)
}
// Check for priority drivers first
for _, name := range priority {
driver, lastError = GetDriver(name, root)
if lastError != nil {
utils.Debugf("Error loading driver %s: %s", name, lastError)
continue
}
return driver, nil
}
// Check all registered drivers if no priority driver is found
for _, initFunc := range drivers {
driver, lastError = initFunc(root)
if lastError != nil {
continue
}
return driver, nil
}
return nil, lastError
}