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moby--moby/daemon/names.go
Aaron Lehmann 1128fc1add Store container names in memdb
Currently, names are maintained by a separate system called "registrar".
This means there is no way to atomically snapshot the state of
containers and the names associated with them.

We can add this atomicity and simplify the code by storing name
associations in the memdb. This removes the need for pkg/registrar, and
makes snapshots a lot less expensive because they no longer need to copy
all the names. This change also avoids some problematic behavior from
pkg/registrar where it returns slices which may be modified later on.

Note that while this change makes the *snapshotting* atomic, it doesn't
yet do anything to make sure containers are named at the same time that
they are added to the database. We can do that by adding a transactional
interface, either as a followup, or as part of this PR.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2017-07-13 12:35:00 -07:00

111 lines
2.7 KiB
Go

package daemon
import (
"fmt"
"strings"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/api"
"github.com/docker/docker/container"
"github.com/docker/docker/pkg/namesgenerator"
"github.com/docker/docker/pkg/stringid"
)
var (
validContainerNameChars = api.RestrictedNameChars
validContainerNamePattern = api.RestrictedNamePattern
)
func (daemon *Daemon) registerName(container *container.Container) error {
if daemon.Exists(container.ID) {
return fmt.Errorf("Container is already loaded")
}
if err := validateID(container.ID); err != nil {
return err
}
if container.Name == "" {
name, err := daemon.generateNewName(container.ID)
if err != nil {
return err
}
container.Name = name
}
return daemon.containersReplica.ReserveName(container.Name, container.ID)
}
func (daemon *Daemon) generateIDAndName(name string) (string, string, error) {
var (
err error
id = stringid.GenerateNonCryptoID()
)
if name == "" {
if name, err = daemon.generateNewName(id); err != nil {
return "", "", err
}
return id, name, nil
}
if name, err = daemon.reserveName(id, name); err != nil {
return "", "", err
}
return id, name, nil
}
func (daemon *Daemon) reserveName(id, name string) (string, error) {
if !validContainerNamePattern.MatchString(strings.TrimPrefix(name, "/")) {
return "", fmt.Errorf("Invalid container name (%s), only %s are allowed", name, validContainerNameChars)
}
if name[0] != '/' {
name = "/" + name
}
if err := daemon.containersReplica.ReserveName(name, id); err != nil {
if err == container.ErrNameReserved {
id, err := daemon.containersReplica.Snapshot().GetID(name)
if err != nil {
logrus.Errorf("got unexpected error while looking up reserved name: %v", err)
return "", err
}
return "", fmt.Errorf("Conflict. The container name %q is already in use by container %q. You have to remove (or rename) that container to be able to reuse that name.", name, id)
}
return "", fmt.Errorf("error reserving name: %q, error: %v", name, err)
}
return name, nil
}
func (daemon *Daemon) releaseName(name string) {
daemon.containersReplica.ReleaseName(name)
}
func (daemon *Daemon) generateNewName(id string) (string, error) {
var name string
for i := 0; i < 6; i++ {
name = namesgenerator.GetRandomName(i)
if name[0] != '/' {
name = "/" + name
}
if err := daemon.containersReplica.ReserveName(name, id); err != nil {
if err == container.ErrNameReserved {
continue
}
return "", err
}
return name, nil
}
name = "/" + stringid.TruncateID(id)
if err := daemon.containersReplica.ReserveName(name, id); err != nil {
return "", err
}
return name, nil
}
func validateID(id string) error {
if id == "" {
return fmt.Errorf("Invalid empty id")
}
return nil
}