moby/links.go
2013-10-30 13:06:43 -07:00

144 lines
3.6 KiB
Go

package docker
import (
"fmt"
"github.com/dotcloud/docker/iptables"
"path"
"strings"
)
type Link struct {
ParentIP string
ChildIP string
Name string
BridgeInterface string
ChildEnvironment []string
Ports []Port
IsEnabled bool
}
func NewLink(parent, child *Container, name, bridgeInterface string) (*Link, error) {
if parent.ID == child.ID {
return nil, fmt.Errorf("Cannot link to self: %s == %s", parent.ID, child.ID)
}
if !child.State.Running {
return nil, fmt.Errorf("Cannot link to a non running container: %s AS %s", child.Name, name)
}
ports := make([]Port, len(child.Config.ExposedPorts))
var i int
for p := range child.Config.ExposedPorts {
ports[i] = p
i++
}
l := &Link{
BridgeInterface: bridgeInterface,
Name: name,
ChildIP: child.NetworkSettings.IPAddress,
ParentIP: parent.NetworkSettings.IPAddress,
ChildEnvironment: child.Config.Env,
Ports: ports,
}
return l, nil
}
func (l *Link) Alias() string {
_, alias := path.Split(l.Name)
return alias
}
func (l *Link) ToEnv() []string {
env := []string{}
alias := strings.ToUpper(l.Alias())
if p := l.getDefaultPort(); p != nil {
env = append(env, fmt.Sprintf("%s_PORT=%s://%s:%s", alias, p.Proto(), l.ChildIP, p.Port()))
}
// Load exposed ports into the environment
for _, p := range l.Ports {
env = append(env, fmt.Sprintf("%s_PORT_%s_%s=%s://%s:%s", alias, p.Port(), strings.ToUpper(p.Proto()), p.Proto(), l.ChildIP, p.Port()))
env = append(env, fmt.Sprintf("%s_PORT_%s_%s_ADDR=%s", alias, p.Port(), strings.ToUpper(p.Proto()), l.ChildIP))
env = append(env, fmt.Sprintf("%s_PORT_%s_%s_PORT=%s", alias, p.Port(), strings.ToUpper(p.Proto()), p.Port()))
env = append(env, fmt.Sprintf("%s_PORT_%s_%s_PROTO=%s", alias, p.Port(), strings.ToUpper(p.Proto()), p.Proto()))
}
// Load the linked container's name into the environment
env = append(env, fmt.Sprintf("%s_NAME=%s", alias, l.Name))
if l.ChildEnvironment != nil {
for _, v := range l.ChildEnvironment {
parts := strings.Split(v, "=")
if len(parts) != 2 {
continue
}
// Ignore a few variables that are added during docker build
if parts[0] == "HOME" || parts[0] == "PATH" {
continue
}
env = append(env, fmt.Sprintf("%s_ENV_%s=%s", alias, parts[0], parts[1]))
}
}
return env
}
// Default port rules
func (l *Link) getDefaultPort() *Port {
var p Port
i := len(l.Ports)
if i == 0 {
return nil
} else if i > 1 {
sortPorts(l.Ports, func(ip, jp Port) bool {
// If the two ports have the same number, tcp takes priority
// Sort in desc order
return ip.Int() < jp.Int() || (ip.Int() == jp.Int() && strings.ToLower(ip.Proto()) == "tcp")
})
}
p = l.Ports[0]
return &p
}
func (l *Link) Enable() error {
if err := l.toggle("-I", false); err != nil {
return err
}
l.IsEnabled = true
return nil
}
func (l *Link) Disable() {
// We do not care about errors here because the link may not
// exist in iptables
l.toggle("-D", true)
l.IsEnabled = false
}
func (l *Link) toggle(action string, ignoreErrors bool) error {
for _, p := range l.Ports {
if err := iptables.Raw(action, "FORWARD",
"-i", l.BridgeInterface, "-o", l.BridgeInterface,
"-p", p.Proto(),
"-s", l.ParentIP,
"--dport", p.Port(),
"-d", l.ChildIP,
"-j", "ACCEPT"); !ignoreErrors && err != nil {
return err
}
if err := iptables.Raw(action, "FORWARD",
"-i", l.BridgeInterface, "-o", l.BridgeInterface,
"-p", p.Proto(),
"-s", l.ChildIP,
"--sport", p.Port(),
"-d", l.ParentIP,
"-j", "ACCEPT"); !ignoreErrors && err != nil {
return err
}
}
return nil
}