traefik/vendor/github.com/rancher/go-rancher-metadata/metadata/change.go

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package metadata
import (
"encoding/json"
"fmt"
"time"
2018-01-22 11:16:03 +00:00
"github.com/sirupsen/logrus"
)
func (m *client) OnChangeWithError(intervalSeconds int, do func(string)) error {
return m.onChangeFromVersionWithError("init", intervalSeconds, do)
}
func (m *client) onChangeFromVersionWithError(version string, intervalSeconds int, do func(string)) error {
for {
newVersion, err := m.waitVersion(intervalSeconds, version)
if err != nil {
return err
} else if version == newVersion {
logrus.Debug("No changes in metadata version")
} else {
logrus.Debugf("Metadata Version has been changed. Old version: %s. New version: %s.", version, newVersion)
version = newVersion
do(newVersion)
}
}
return nil
}
func (m *client) OnChange(intervalSeconds int, do func(string)) {
version := "init"
updateVersionAndDo := func(v string) {
version = v
do(version)
}
interval := time.Duration(intervalSeconds)
for {
if err := m.onChangeFromVersionWithError(version, intervalSeconds, updateVersionAndDo); err != nil {
logrus.Errorf("Error reading metadata version: %v", err)
}
time.Sleep(interval * time.Second)
}
}
type timeout interface {
Timeout() bool
}
func (m *client) waitVersion(maxWait int, version string) (string, error) {
for {
resp, err := m.SendRequest(fmt.Sprintf("/version?wait=true&value=%s&maxWait=%d", version, maxWait))
if err != nil {
t, ok := err.(timeout)
if ok && t.Timeout() {
continue
}
return "", err
}
err = json.Unmarshal(resp, &version)
return version, err
}
}