93 lines
1.8 KiB
Go
93 lines
1.8 KiB
Go
package memory
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import (
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"sync"
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"time"
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"github.com/docker/docker/pkg/discovery"
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)
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// Discovery implements a discovery backend that keeps
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// data in memory.
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type Discovery struct {
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heartbeat time.Duration
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values []string
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mu sync.Mutex
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}
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func init() {
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Init()
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}
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// Init registers the memory backend on demand.
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func Init() {
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discovery.Register("memory", &Discovery{})
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}
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// Initialize sets the heartbeat for the memory backend.
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func (s *Discovery) Initialize(_ string, heartbeat time.Duration, _ time.Duration, _ map[string]string) error {
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s.heartbeat = heartbeat
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s.values = make([]string, 0)
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return nil
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}
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// Watch sends periodic discovery updates to a channel.
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func (s *Discovery) Watch(stopCh <-chan struct{}) (<-chan discovery.Entries, <-chan error) {
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ch := make(chan discovery.Entries)
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errCh := make(chan error)
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ticker := time.NewTicker(s.heartbeat)
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go func() {
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defer close(errCh)
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defer close(ch)
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// Send the initial entries if available.
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var currentEntries discovery.Entries
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var err error
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s.mu.Lock()
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if len(s.values) > 0 {
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currentEntries, err = discovery.CreateEntries(s.values)
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}
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s.mu.Unlock()
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if err != nil {
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errCh <- err
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} else if currentEntries != nil {
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ch <- currentEntries
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}
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// Periodically send updates.
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for {
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select {
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case <-ticker.C:
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s.mu.Lock()
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newEntries, err := discovery.CreateEntries(s.values)
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s.mu.Unlock()
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if err != nil {
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errCh <- err
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continue
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}
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// Check if the file has really changed.
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if !newEntries.Equals(currentEntries) {
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ch <- newEntries
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}
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currentEntries = newEntries
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case <-stopCh:
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ticker.Stop()
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return
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}
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}
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}()
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return ch, errCh
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}
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// Register adds a new address to the discovery.
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func (s *Discovery) Register(addr string) error {
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s.mu.Lock()
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s.values = append(s.values, addr)
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s.mu.Unlock()
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return nil
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}
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