open-nomad/nomad/drainer/job_watcher.go
2018-03-21 16:51:44 -07:00

141 lines
3.4 KiB
Go

package drainer
import (
"context"
"log"
"sync"
memdb "github.com/hashicorp/go-memdb"
"github.com/hashicorp/nomad/nomad/state"
"github.com/hashicorp/nomad/nomad/structs"
)
// jobWatcher watches allocation changes for jobs with at least one allocation
// on a draining node.
type jobWatcher struct {
// allocsIndex to start watching from
allocsIndex uint64
// job -> node.ID
jobs map[jobKey]string
jobsMu sync.Mutex
jobsCh chan map[jobKey]struct{}
state *state.StateStore
logger *log.Logger
}
func newJobWatcher(logger *log.Logger, jobs map[jobKey]string, allocsIndex uint64, state *state.StateStore) *jobWatcher {
return &jobWatcher{
allocsIndex: allocsIndex,
logger: logger,
jobs: jobs,
jobsCh: make(chan map[jobKey]struct{}),
state: state,
}
}
func (j *jobWatcher) watch(k jobKey, nodeID string) {
j.logger.Printf("[TRACE] nomad.drain: watching job %s on draining node %s", k.jobid, nodeID[:6])
j.jobsMu.Lock()
j.jobs[k] = nodeID
j.jobsMu.Unlock()
}
func (j *jobWatcher) nodeDone(nodeID string) {
j.jobsMu.Lock()
defer j.jobsMu.Unlock()
for k, v := range j.jobs {
if v == nodeID {
j.logger.Printf("[TRACE] nomad.drain: UNwatching job %s on done draining node %s", k.jobid, nodeID[:6])
delete(j.jobs, k)
}
}
}
func (j *jobWatcher) WaitCh() <-chan map[jobKey]struct{} {
return j.jobsCh
}
func (j *jobWatcher) run(ctx context.Context) {
var resp interface{}
var err error
for {
//FIXME have watchAllocs create a closure and give it a copy of j.jobs to remove locking?
//FIXME it seems possible for this to return a nil error and a 0 index, what to do in that case?
var newIndex uint64
resp, newIndex, err = j.state.BlockingQuery(j.watchAllocs, j.allocsIndex, ctx)
if err != nil {
if err == context.Canceled {
j.logger.Printf("[TRACE] nomad.drain: job watcher shutting down")
return
}
j.logger.Printf("[ERR] nomad.drain: error blocking on alloc updates: %v", err)
return
}
j.logger.Printf("[TRACE] nomad.drain: job watcher old index: %d new index: %d", j.allocsIndex, newIndex)
j.allocsIndex = newIndex
changedJobs := resp.(map[jobKey]struct{})
if len(changedJobs) > 0 {
select {
case j.jobsCh <- changedJobs:
case <-ctx.Done():
return
}
}
}
}
func (j *jobWatcher) watchAllocs(ws memdb.WatchSet, state *state.StateStore) (interface{}, uint64, error) {
iter, err := state.Allocs(ws)
if err != nil {
return nil, 0, err
}
index, err := state.Index("allocs")
if err != nil {
return nil, 0, err
}
skipped := 0
// job ids
resp := map[jobKey]struct{}{}
for {
raw := iter.Next()
if raw == nil {
break
}
alloc := raw.(*structs.Allocation)
j.jobsMu.Lock()
_, ok := j.jobs[jobKey{alloc.Namespace, alloc.JobID}]
j.jobsMu.Unlock()
if !ok {
// alloc is not part of a draining job
skipped++
continue
}
// don't wake drain loop if alloc hasn't updated its health
if alloc.DeploymentStatus.IsHealthy() || alloc.DeploymentStatus.IsUnhealthy() {
j.logger.Printf("[TRACE] nomad.drain: job watcher found alloc %s - deployment status: %t", alloc.ID[:6], *alloc.DeploymentStatus.Healthy)
resp[jobKey{alloc.Namespace, alloc.JobID}] = struct{}{}
} else {
j.logger.Printf("[TRACE] nomad.drain: job watcher ignoring alloc %s - no deployment status", alloc.ID[:6])
}
}
j.logger.Printf("[TRACE] nomad.drain: job watcher ignoring %d allocs - not part of draining job at index %d", skipped, index)
return resp, index, nil
}