зеркало из https://github.com/microsoft/docker.git
93 строки
2.8 KiB
Go
93 строки
2.8 KiB
Go
package daemon
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import (
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"fmt"
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"strconv"
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"time"
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log "github.com/Sirupsen/logrus"
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"github.com/docker/docker/pkg/discovery"
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// Register the libkv backends for discovery.
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_ "github.com/docker/docker/pkg/discovery/kv"
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)
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const (
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// defaultDiscoveryHeartbeat is the default value for discovery heartbeat interval.
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defaultDiscoveryHeartbeat = 20 * time.Second
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// defaultDiscoveryTTLFactor is the default TTL factor for discovery
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defaultDiscoveryTTLFactor = 3
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)
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func discoveryOpts(clusterOpts map[string]string) (time.Duration, time.Duration, error) {
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var (
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heartbeat = defaultDiscoveryHeartbeat
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ttl = defaultDiscoveryTTLFactor * defaultDiscoveryHeartbeat
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)
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if hb, ok := clusterOpts["discovery.heartbeat"]; ok {
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h, err := strconv.Atoi(hb)
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if err != nil {
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return time.Duration(0), time.Duration(0), err
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}
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heartbeat = time.Duration(h) * time.Second
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ttl = defaultDiscoveryTTLFactor * heartbeat
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}
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if tstr, ok := clusterOpts["discovery.ttl"]; ok {
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t, err := strconv.Atoi(tstr)
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if err != nil {
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return time.Duration(0), time.Duration(0), err
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}
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ttl = time.Duration(t) * time.Second
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if _, ok := clusterOpts["discovery.heartbeat"]; !ok {
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h := int(t / defaultDiscoveryTTLFactor)
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heartbeat = time.Duration(h) * time.Second
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}
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if ttl <= heartbeat {
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return time.Duration(0), time.Duration(0),
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fmt.Errorf("discovery.ttl timer must be greater than discovery.heartbeat")
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}
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}
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return heartbeat, ttl, nil
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}
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// initDiscovery initialized the nodes discovery subsystem by connecting to the specified backend
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// and start a registration loop to advertise the current node under the specified address.
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func initDiscovery(backend, address string, clusterOpts map[string]string) (discovery.Backend, error) {
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heartbeat, ttl, err := discoveryOpts(clusterOpts)
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if err != nil {
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return nil, err
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}
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discoveryBackend, err := discovery.New(backend, heartbeat, ttl, clusterOpts)
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if err != nil {
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return nil, err
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}
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// We call Register() on the discovery backend in a loop for the whole lifetime of the daemon,
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// but we never actually Watch() for nodes appearing and disappearing for the moment.
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go registrationLoop(discoveryBackend, address, heartbeat)
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return discoveryBackend, nil
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}
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func registerAddr(backend discovery.Backend, addr string) {
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if err := backend.Register(addr); err != nil {
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log.Warnf("Registering as %q in discovery failed: %v", addr, err)
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}
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}
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// registrationLoop registers the current node against the discovery backend using the specified
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// address. The function never returns, as registration against the backend comes with a TTL and
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// requires regular heartbeats.
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func registrationLoop(discoveryBackend discovery.Backend, address string, heartbeat time.Duration) {
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registerAddr(discoveryBackend, address)
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for range time.Tick(heartbeat) {
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registerAddr(discoveryBackend, address)
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}
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}
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