package links // import "github.com/docker/docker/daemon/links" import ( "fmt" "path" "strings" "github.com/docker/go-connections/nat" ) // Link struct holds information about parent/child linked container type Link struct { // Parent container IP address ParentIP string // Child container IP address ChildIP string // Link name Name string // Child environments variables ChildEnvironment []string // Child exposed ports Ports []nat.Port } // NewLink initializes a new Link struct with the provided options. func NewLink(parentIP, childIP, name string, env []string, exposedPorts map[nat.Port]struct{}) *Link { var ( i int ports = make([]nat.Port, len(exposedPorts)) ) for p := range exposedPorts { ports[i] = p i++ } return &Link{ Name: name, ChildIP: childIP, ParentIP: parentIP, ChildEnvironment: env, Ports: ports, } } // ToEnv creates a string's slice containing child container information in // the form of environment variables which will be later exported on container // startup. func (l *Link) ToEnv() []string { env := []string{} _, n := path.Split(l.Name) alias := strings.Replace(strings.ToUpper(n), "-", "_", -1) if p := l.getDefaultPort(); p != nil { env = append(env, fmt.Sprintf("%s_PORT=%s://%s:%s", alias, p.Proto(), l.ChildIP, p.Port())) } // sort the ports so that we can bulk the continuous ports together nat.Sort(l.Ports, func(ip, jp nat.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") }) for i := 0; i < len(l.Ports); { p := l.Ports[i] j := nextContiguous(l.Ports, p.Int(), i) if j > i+1 { env = append(env, fmt.Sprintf("%s_PORT_%s_%s_START=%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_PROTO=%s", alias, p.Port(), strings.ToUpper(p.Proto()), p.Proto())) env = append(env, fmt.Sprintf("%s_PORT_%s_%s_PORT_START=%s", alias, p.Port(), strings.ToUpper(p.Proto()), p.Port())) q := l.Ports[j] env = append(env, fmt.Sprintf("%s_PORT_%s_%s_END=%s://%s:%s", alias, p.Port(), strings.ToUpper(q.Proto()), q.Proto(), l.ChildIP, q.Port())) env = append(env, fmt.Sprintf("%s_PORT_%s_%s_PORT_END=%s", alias, p.Port(), strings.ToUpper(q.Proto()), q.Port())) i = j + 1 continue } else { i++ } } 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.SplitN(v, "=", 2) if len(parts) < 2 { continue } // Ignore a few variables that are added during docker build (and not really relevant to linked containers) if parts[0] == "HOME" || parts[0] == "PATH" { continue } env = append(env, fmt.Sprintf("%s_ENV_%s=%s", alias, parts[0], parts[1])) } } return env } func nextContiguous(ports []nat.Port, value int, index int) int { if index+1 == len(ports) { return index } for i := index + 1; i < len(ports); i++ { if ports[i].Int() > value+1 { return i - 1 } value++ } return len(ports) - 1 } // Default port rules func (l *Link) getDefaultPort() *nat.Port { var p nat.Port i := len(l.Ports) if i == 0 { return nil } else if i > 1 { nat.Sort(l.Ports, func(ip, jp nat.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 }