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package metadata
import (
"context"
"encoding/json"
"fmt"
"time"
"github.com/sirupsen/logrus"
)
type timeout interface {
Timeout() bool
}
func (m *client) OnChangeWithError(intervalSeconds int, do func(string)) error {
return m.onChangeFromVersionWithError("init", intervalSeconds, do)
}
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)
}
}
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)
}
}
}
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
}
}
func (m *client) OnChangeCtx(ctx context.Context, intervalSeconds int, do func(string)) {
m.onChangeFromVersionWithErrorCtx(ctx, "init", intervalSeconds, do)
}
func (m *client) onChangeFromVersionWithErrorCtx(ctx context.Context, version string, intervalSeconds int, do func(string)) {
for {
select {
case <-ctx.Done():
return
default:
}
newVersion, err := m.waitVersionCtx(ctx, intervalSeconds, version)
if err != nil {
t, ok := err.(timeout)
if !ok || !t.Timeout() {
logrus.Errorf("Error reading metadata version: %v", err)
time.Sleep(time.Duration(intervalSeconds) * time.Second)
}
continue
}
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)
}
}
}
func (m *client) waitVersionCtx(ctx context.Context, maxWait int, version string) (string, error) {
resp, err := m.SendRequestCtx(ctx, fmt.Sprintf("/version?wait=true&value=%s&maxWait=%d", version, maxWait))
if err != nil {
return "", err
}
err = json.Unmarshal(resp, &version)
return version, err
}
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