110 lines
2.2 KiB
Go
110 lines
2.2 KiB
Go
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package file
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import (
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"fmt"
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"io/ioutil"
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"strings"
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"time"
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"github.com/docker/docker/pkg/discovery"
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)
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// Discovery is exported
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type Discovery struct {
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heartbeat time.Duration
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path string
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}
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func init() {
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Init()
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}
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// Init is exported
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func Init() {
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discovery.Register("file", &Discovery{})
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}
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// Initialize is exported
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func (s *Discovery) Initialize(path string, heartbeat time.Duration, ttl time.Duration) error {
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s.path = path
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s.heartbeat = heartbeat
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return nil
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}
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func parseFileContent(content []byte) []string {
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var result []string
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for _, line := range strings.Split(strings.TrimSpace(string(content)), "\n") {
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line = strings.TrimSpace(line)
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// Ignoring line starts with #
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if strings.HasPrefix(line, "#") {
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continue
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}
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// Inlined # comment also ignored.
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if strings.Contains(line, "#") {
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line = line[0:strings.Index(line, "#")]
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// Trim additional spaces caused by above stripping.
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line = strings.TrimSpace(line)
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}
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for _, ip := range discovery.Generate(line) {
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result = append(result, ip)
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}
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}
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return result
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}
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func (s *Discovery) fetch() (discovery.Entries, error) {
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fileContent, err := ioutil.ReadFile(s.path)
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if err != nil {
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return nil, fmt.Errorf("failed to read '%s': %v", s.path, err)
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}
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return discovery.CreateEntries(parseFileContent(fileContent))
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}
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// Watch is exported
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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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currentEntries, err := s.fetch()
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if err != nil {
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errCh <- err
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} else {
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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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newEntries, err := s.fetch()
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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 is exported
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func (s *Discovery) Register(addr string) error {
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return discovery.ErrNotImplemented
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}
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