// UpdateDeps is used to update the values of the dependencies for a template
func (d *DedupManager) UpdateDeps(t *template.Template, deps []dep.Dependency) error {
// Calculate the path to write updates to
dataPath := path.Join(*d.config.Prefix, t.ID(), "data")
// Package up the dependency data
td := templateData{
Data: make(map[string]interface{}),
}
for _, dp := range deps {
// Skip any dependencies that can't be shared
if !dp.CanShare() {
continue
}
// Pull the current value from the brain
val, ok := d.brain.Recall(dp)
if ok {
td.Data[dp.String()] = val
}
}
// Encode via GOB and LZW compress
var buf bytes.Buffer
compress := lzw.NewWriter(&buf, lzw.LSB, 8)
enc := gob.NewEncoder(compress)
if err := enc.Encode(&td); err != nil {
return fmt.Errorf("encode failed: %v", err)
}
compress.Close()
// Compute MD5 of the buffer
hash := md5.Sum(buf.Bytes())
d.lastWriteLock.RLock()
existing, ok := d.lastWrite[t]
d.lastWriteLock.RUnlock()
if ok && bytes.Equal(existing, hash[:]) {
log.Printf("[INFO] (dedup) de-duplicate data '%s' already current",
dataPath)
return nil
}
// Write the KV update
kvPair := consulapi.KVPair{
Key: dataPath,
Value: buf.Bytes(),
Flags: templateDataFlag,
}
client := d.clients.Consul()
if _, err := client.KV().Put(&kvPair, nil); err != nil {
return fmt.Errorf("failed to write '%s': %v", dataPath, err)
}
log.Printf("[INFO] (dedup) updated de-duplicate data '%s'", dataPath)
d.lastWriteLock.Lock()
d.lastWrite[t] = hash[:]
d.lastWriteLock.Unlock()
return nil
}
func (d *DedupManager) attemptLock(client *consulapi.Client, session string, sessionCh chan struct{}, t *template.Template) {
defer d.wg.Done()
START:
log.Printf("[INFO] (dedup) attempting lock for template hash %s", t.ID())
basePath := path.Join(*d.config.Prefix, t.ID())
lopts := &consulapi.LockOptions{
Key: path.Join(basePath, "lock"),
Session: session,
MonitorRetries: 3,
MonitorRetryTime: 3 * time.Second,
}
lock, err := client.LockOpts(lopts)
if err != nil {
log.Printf("[ERR] (dedup) failed to create lock '%s': %v",
lopts.Key, err)
return
}
var retryCh <-chan time.Time
leaderCh, err := lock.Lock(sessionCh)
if err != nil {
log.Printf("[ERR] (dedup) failed to acquire lock '%s': %v",
lopts.Key, err)
retryCh = time.After(lockRetry)
} else {
log.Printf("[INFO] (dedup) acquired lock '%s'", lopts.Key)
d.setLeader(t, leaderCh)
}
select {
case <-retryCh:
retryCh = nil
goto START
case <-leaderCh:
log.Printf("[WARN] (dedup) lost lock ownership '%s'", lopts.Key)
d.setLeader(t, nil)
goto START
case <-sessionCh:
log.Printf("[INFO] (dedup) releasing lock '%s'", lopts.Key)
d.setLeader(t, nil)
lock.Unlock()
case <-d.stopCh:
log.Printf("[INFO] (dedup) releasing lock '%s'", lopts.Key)
lock.Unlock()
}
}
// TemplateConfigFor returns the TemplateConfig for the given Template
func (r *Runner) templateConfigsFor(tmpl *template.Template) []*config.TemplateConfig {
return r.ctemplatesMap[tmpl.ID()]
}
// ConfigTemplateFor returns the ConfigTemplate for the given Template
func (r *Runner) configTemplatesFor(tmpl *template.Template) []*config.ConfigTemplate {
return r.ctemplatesMap[tmpl.ID()]
}
func (d *DedupManager) watchTemplate(client *consulapi.Client, t *template.Template) {
log.Printf("[INFO] (dedup) starting watch for template hash %s", t.ID())
path := path.Join(*d.config.Prefix, t.ID(), "data")
// Determine if stale queries are allowed
var allowStale bool
if *d.config.MaxStale != 0 {
allowStale = true
}
// Setup our query options
opts := &consulapi.QueryOptions{
AllowStale: allowStale,
WaitTime: 60 * time.Second,
}
START:
// Stop listening if we're stopped
select {
case <-d.stopCh:
return
default:
}
// If we are current the leader, wait for leadership lost
d.leaderLock.RLock()
lockCh, ok := d.leader[t]
d.leaderLock.RUnlock()
if ok {
select {
case <-lockCh:
goto START
case <-d.stopCh:
return
}
}
// Block for updates on the data key
log.Printf("[INFO] (dedup) listing data for template hash %s", t.ID())
pair, meta, err := client.KV().Get(path, opts)
if err != nil {
log.Printf("[ERR] (dedup) failed to get '%s': %v", path, err)
select {
case <-time.After(listRetry):
goto START
case <-d.stopCh:
return
}
}
opts.WaitIndex = meta.LastIndex
// If we've exceeded the maximum staleness, retry without stale
if allowStale && meta.LastContact > *d.config.MaxStale {
allowStale = false
log.Printf("[DEBUG] (dedup) %s stale data (last contact exceeded max_stale)", path)
goto START
}
// Re-enable stale queries if allowed
if *d.config.MaxStale > 0 {
allowStale = true
}
// Stop listening if we're stopped
select {
case <-d.stopCh:
return
default:
}
// If we are current the leader, wait for leadership lost
d.leaderLock.RLock()
lockCh, ok = d.leader[t]
d.leaderLock.RUnlock()
if ok {
select {
case <-lockCh:
goto START
case <-d.stopCh:
return
}
}
// Parse the data file
if pair != nil && pair.Flags == templateDataFlag {
d.parseData(pair.Key, pair.Value)
}
goto START
}
