9cb07d026f
Introduces Rancher's metadata service as an optional provider source for Traefik, enabled by setting `rancher.MetadataService`. The provider uses a long polling technique to watch the metadata service and obtain near instantaneous updates. Alternatively it can be configured to poll the metadata service every `rancher.RefreshSeconds` by setting `rancher.MetadataPoll`. The refactor splits API and metadata service code into separate source files respectively, and specific configuration is deferred to sub-structs. Incorporates bugfix #1414
64 lines
1.5 KiB
Go
64 lines
1.5 KiB
Go
package metadata
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import (
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"encoding/json"
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"fmt"
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"time"
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"github.com/Sirupsen/logrus"
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)
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func (m *client) OnChangeWithError(intervalSeconds int, do func(string)) error {
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return m.onChangeFromVersionWithError("init", intervalSeconds, do)
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}
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func (m *client) onChangeFromVersionWithError(version string, intervalSeconds int, do func(string)) error {
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for {
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newVersion, err := m.waitVersion(intervalSeconds, version)
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if err != nil {
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return err
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} else if version == newVersion {
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logrus.Debug("No changes in metadata version")
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} else {
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logrus.Debugf("Metadata Version has been changed. Old version: %s. New version: %s.", version, newVersion)
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version = newVersion
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do(newVersion)
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}
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}
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return nil
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}
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func (m *client) OnChange(intervalSeconds int, do func(string)) {
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version := "init"
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updateVersionAndDo := func(v string) {
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version = v
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do(version)
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}
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interval := time.Duration(intervalSeconds)
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for {
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if err := m.onChangeFromVersionWithError(version, intervalSeconds, updateVersionAndDo); err != nil {
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logrus.Errorf("Error reading metadata version: %v", err)
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}
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time.Sleep(interval * time.Second)
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}
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}
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type timeout interface {
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Timeout() bool
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}
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func (m *client) waitVersion(maxWait int, version string) (string, error) {
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for {
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resp, err := m.SendRequest(fmt.Sprintf("/version?wait=true&value=%s&maxWait=%d", version, maxWait))
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if err != nil {
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t, ok := err.(timeout)
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if ok && t.Timeout() {
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continue
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}
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return "", err
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}
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err = json.Unmarshal(resp, &version)
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return version, err
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}
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}
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