forked from flynn/flynn
/
state.go
542 lines (483 loc) · 13.2 KB
/
state.go
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package main
import (
"encoding/json"
"errors"
"fmt"
"io"
"log"
"net"
"os"
"path/filepath"
"sync"
"time"
"github.com/boltdb/bolt"
"github.com/flynn/flynn/host/types"
"github.com/flynn/flynn/pkg/cluster"
)
// TODO: prune old jobs?
// ErrJobExists is returned when attempting to add a job to the state with an
// ID which already exists
var ErrJobExists = errors.New("job already exists")
type State struct {
id string
jobs map[string]*host.ActiveJob
mtx sync.RWMutex
containers map[string]*host.ActiveJob // container ID -> job
listeners map[string]map[chan host.Event]struct{} // job id -> listener list (ID "all" gets all events)
listenMtx sync.RWMutex
attachers map[string]map[chan struct{}]struct{}
stateFilePath string
stateDB *bolt.DB
dbUsers int
dbCond *sync.Cond
backend Backend
}
func NewState(id string, stateFilePath string) *State {
return &State{
id: id,
stateFilePath: stateFilePath,
jobs: make(map[string]*host.ActiveJob),
containers: make(map[string]*host.ActiveJob),
listeners: make(map[string]map[chan host.Event]struct{}),
attachers: make(map[string]map[chan struct{}]struct{}),
dbCond: sync.NewCond(&sync.Mutex{}),
}
}
/*
Restore prior state from the save location defined at construction time.
If the state save file is empty, nothing is loaded, and no error is returned.
*/
func (s *State) Restore(backend Backend, buffers host.LogBuffers) (func(), error) {
if err := s.Acquire(); err != nil {
return nil, err
}
defer s.Release()
s.backend = backend
var resurrect []*host.Job
if err := s.stateDB.View(func(tx *bolt.Tx) error {
jobsBucket := tx.Bucket([]byte("jobs"))
backendJobsBucket := tx.Bucket([]byte("backend-jobs"))
backendGlobalBucket := tx.Bucket([]byte("backend-global"))
persistentBucket := tx.Bucket([]byte("persistent-jobs"))
// restore jobs
if err := jobsBucket.ForEach(func(k, v []byte) error {
job := &host.ActiveJob{}
if err := json.Unmarshal(v, job); err != nil {
return err
}
if job.CreatedAt.IsZero() {
job.CreatedAt = time.Now()
}
if job.ContainerID != "" {
s.containers[job.ContainerID] = job
}
s.jobs[string(k)] = job
return nil
}); err != nil {
return err
}
// hand opaque blobs back to backend so it can do its restore
backendJobsBlobs := make(map[string][]byte)
if err := backendJobsBucket.ForEach(func(k, v []byte) error {
backendJobsBlobs[string(k)] = v
return nil
}); err != nil {
return err
}
backendGlobalBlob := backendGlobalBucket.Get([]byte("backend"))
if err := backend.UnmarshalState(s.jobs, backendJobsBlobs, backendGlobalBlob, buffers); err != nil {
return err
}
// resurrect any persistent jobs which are not running
if err := persistentBucket.ForEach(func(k, v []byte) error {
for _, job := range s.jobs {
if job.Job.ID == string(v) && !backend.JobExists(job.Job.ID) {
resurrect = append(resurrect, job.Job)
}
}
return nil
}); err != nil {
return err
}
return nil
}); err != nil && err != io.EOF {
return nil, fmt.Errorf("could not restore from host persistence db: %s", err)
}
return func() {
if len(resurrect) == 0 {
return
}
var wg sync.WaitGroup
wg.Add(len(resurrect))
for _, job := range resurrect {
go func(job *host.Job) {
// generate a new job id, this is a new job
newJob := job.Dup()
newJob.ID = cluster.GenerateJobID(s.id, "")
log.Printf("resurrecting %s as %s", job.ID, newJob.ID)
s.AddJob(newJob)
backend.Run(newJob, nil, nil)
wg.Done()
}(job)
}
wg.Wait()
}, nil
}
// OpenDB opens and initialises the persistence DB, if not already open.
func (s *State) OpenDB() error {
s.dbCond.L.Lock()
defer s.dbCond.L.Unlock()
if s.stateDB != nil {
return nil
}
// open/initialize db
if err := os.MkdirAll(filepath.Dir(s.stateFilePath), 0755); err != nil {
return fmt.Errorf("could not not mkdir for db: %s", err)
}
stateDB, err := bolt.Open(s.stateFilePath, 0600, &bolt.Options{Timeout: 5 * time.Second})
if err != nil {
return fmt.Errorf("could not open db: %s", err)
}
s.stateDB = stateDB
if err := s.stateDB.Update(func(tx *bolt.Tx) error {
// idempotently create buckets. (errors ignored because they're all compile-time impossible args checks.)
tx.CreateBucketIfNotExists([]byte("jobs"))
tx.CreateBucketIfNotExists([]byte("backend-jobs"))
tx.CreateBucketIfNotExists([]byte("backend-global"))
tx.CreateBucketIfNotExists([]byte("persistent-jobs"))
return nil
}); err != nil {
return fmt.Errorf("could not initialize host persistence db: %s", err)
}
return nil
}
// CloseDB closes the persistence DB, waiting for the state to be fully
// released first.
func (s *State) CloseDB() error {
s.dbCond.L.Lock()
defer s.dbCond.L.Unlock()
if s.stateDB == nil {
return nil
}
for s.dbUsers > 0 {
s.dbCond.Wait()
}
if err := s.stateDB.Close(); err != nil {
return err
}
s.stateDB = nil
return nil
}
var ErrDBClosed = errors.New("state DB closed")
// Acquire acquires the state for use by incrementing s.dbUsers, which prevents
// the state DB being closed until the caller has finished performing actions
// which will lead to changes being persisted to the DB.
//
// For example, running a job starts the job and then persists the change of
// state, but if the DB is closed in that time then the state of the running
// job will be lost.
//
// ErrDBClosed is returned if the DB is already closed so API requests will
// fail before any actions are performed.
func (s *State) Acquire() error {
s.dbCond.L.Lock()
defer s.dbCond.L.Unlock()
if s.stateDB == nil {
return ErrDBClosed
}
s.dbUsers++
return nil
}
// Release releases the state by decrementing s.dbUsers, broadcasting the
// condition variable if no users are left to wake CloseDB.
func (s *State) Release() {
s.dbCond.L.Lock()
defer s.dbCond.L.Unlock()
s.dbUsers--
if s.dbUsers == 0 {
s.dbCond.Broadcast()
}
}
func (s *State) PersistBackendGlobalState(data []byte) error {
return s.stateDB.Update(func(tx *bolt.Tx) error {
return tx.Bucket([]byte("backend-global")).Put([]byte("backend"), data)
})
}
func (s *State) persist(jobID string) {
// s.mtx.RLock() should already be covered by caller
if err := s.stateDB.Update(func(tx *bolt.Tx) error {
jobsBucket := tx.Bucket([]byte("jobs"))
backendJobsBucket := tx.Bucket([]byte("backend-jobs"))
backendGlobalBucket := tx.Bucket([]byte("backend-global"))
// serialize the changed job, and push it into jobs bucket
if _, exists := s.jobs[jobID]; exists {
b, err := json.Marshal(s.jobs[jobID])
if err != nil {
return fmt.Errorf("failed to serialize job state: %s", err)
}
err = jobsBucket.Put([]byte(jobID), b)
if err != nil {
return fmt.Errorf("could not persist job to boltdb: %s", err)
}
} else {
jobsBucket.Delete([]byte(jobID))
}
// save the opaque blob the backend provides regarding this job if it is starting/running
if backend, ok := s.backend.(JobStateSaver); ok {
if job, exists := s.jobs[jobID]; exists && (job.Status == host.StatusStarting || job.Status == host.StatusRunning) {
backendState, err := backend.MarshalJobState(jobID)
if err != nil {
return fmt.Errorf("backend failed to serialize job state: %s", err)
}
if backendState == nil {
backendJobsBucket.Delete([]byte(jobID))
} else {
err = backendJobsBucket.Put([]byte(jobID), backendState)
if err != nil {
return fmt.Errorf("could not persist backend job state to boltdb: %s", err)
}
}
} else {
backendJobsBucket.Delete([]byte(jobID))
}
}
// (re)save any state the backend provides that isn't tied to specific jobs.
if backend, ok := s.backend.(StateSaver); ok {
bytes, err := backend.MarshalGlobalState()
if err != nil {
return fmt.Errorf("backend failed to serialize global state: %s", err)
}
err = backendGlobalBucket.Put([]byte("backend"), bytes)
if err != nil {
return fmt.Errorf("could not persist backend global state to boltdb: %s", err)
}
}
return nil
}); err != nil {
panic(fmt.Errorf("could not persist to boltdb: %s", err))
}
}
func (s *State) AddJob(j *host.Job) error {
s.mtx.Lock()
defer s.mtx.Unlock()
if _, ok := s.jobs[j.ID]; ok {
return ErrJobExists
}
job := &host.ActiveJob{
Job: j,
HostID: s.id,
CreatedAt: time.Now(),
}
s.jobs[j.ID] = job
s.sendEvent(job, host.JobEventCreate)
s.persist(j.ID)
return nil
}
func (s *State) GetJob(id string) *host.ActiveJob {
s.mtx.RLock()
defer s.mtx.RUnlock()
job := s.jobs[id]
if job == nil {
return nil
}
return job.Dup()
}
func (s *State) RemoveJob(jobID string) {
s.mtx.Lock()
defer s.mtx.Unlock()
delete(s.jobs, jobID)
s.persist(jobID)
}
func (s *State) Get() map[string]*host.ActiveJob {
s.mtx.RLock()
defer s.mtx.RUnlock()
res := make(map[string]*host.ActiveJob, len(s.jobs))
for k, v := range s.jobs {
res[k] = v.Dup()
}
return res
}
func (s *State) ClusterJobs() []*host.Job {
s.mtx.RLock()
defer s.mtx.RUnlock()
res := make([]*host.Job, 0, len(s.jobs))
for _, j := range s.jobs {
res = append(res, j.Job)
}
return res
}
func (s *State) SetContainerID(jobID, containerID string) {
s.mtx.Lock()
defer s.mtx.Unlock()
s.jobs[jobID].ContainerID = containerID
s.containers[containerID] = s.jobs[jobID]
s.persist(jobID)
}
func (s *State) SetContainerIP(jobID string, ip net.IP) {
s.mtx.Lock()
defer s.mtx.Unlock()
s.jobs[jobID].InternalIP = ip.String()
s.persist(jobID)
}
func (s *State) SetForceStop(jobID string) {
s.mtx.Lock()
defer s.mtx.Unlock()
job, ok := s.jobs[jobID]
if !ok {
return
}
job.ForceStop = true
s.persist(jobID)
}
func (s *State) SetStatusRunning(jobID string) {
s.mtx.Lock()
defer s.mtx.Unlock()
job, ok := s.jobs[jobID]
if !ok || job.Status != host.StatusStarting {
return
}
job.StartedAt = time.Now().UTC()
job.Status = host.StatusRunning
s.sendEvent(job, host.JobEventStart)
if err := s.Acquire(); err == nil {
s.persist(jobID)
s.Release()
}
}
func (s *State) SetContainerStatusDone(containerID string, exitCode int) {
s.mtx.Lock()
defer s.mtx.Unlock()
job, ok := s.containers[containerID]
if !ok {
return
}
s.setStatusDone(job, exitCode)
}
func (s *State) SetStatusDone(jobID string, exitCode int) {
s.mtx.Lock()
defer s.mtx.Unlock()
job, ok := s.jobs[jobID]
if !ok {
fmt.Println("SKIP")
return
}
s.setStatusDone(job, exitCode)
}
func (s *State) setStatusDone(job *host.ActiveJob, exitStatus int) {
if job.Status == host.StatusDone || job.Status == host.StatusCrashed || job.Status == host.StatusFailed {
return
}
job.EndedAt = time.Now().UTC()
job.ExitStatus = &exitStatus
if exitStatus == 0 {
job.Status = host.StatusDone
} else {
job.Status = host.StatusCrashed
}
s.sendEvent(job, host.JobEventStop)
if err := s.Acquire(); err == nil {
s.persist(job.Job.ID)
s.Release()
}
}
func (s *State) SetStatusFailed(jobID string, err error) {
s.mtx.Lock()
defer s.mtx.Unlock()
job, ok := s.jobs[jobID]
if !ok || job.Status == host.StatusDone || job.Status == host.StatusCrashed || job.Status == host.StatusFailed {
return
}
job.Status = host.StatusFailed
job.EndedAt = time.Now().UTC()
errStr := err.Error()
job.Error = &errStr
s.sendEvent(job, host.JobEventError)
if err := s.Acquire(); err == nil {
s.persist(jobID)
s.Release()
}
go s.WaitAttach(jobID)
}
func (s *State) AddAttacher(jobID string, ch chan struct{}) *host.ActiveJob {
s.mtx.Lock()
defer s.mtx.Unlock()
if job, ok := s.jobs[jobID]; ok {
jobCopy := *job
return &jobCopy
}
if _, ok := s.attachers[jobID]; !ok {
s.attachers[jobID] = make(map[chan struct{}]struct{})
}
s.attachers[jobID][ch] = struct{}{}
return nil
}
func (s *State) RemoveAttacher(jobID string, ch chan struct{}) {
s.mtx.Lock()
defer s.mtx.Unlock()
if a, ok := s.attachers[jobID]; ok {
delete(a, ch)
if len(a) == 0 {
delete(s.attachers, jobID)
}
}
}
func (s *State) WaitAttach(jobID string) {
s.mtx.Lock()
a := s.attachers[jobID]
delete(s.attachers, jobID)
s.mtx.Unlock()
for ch := range a {
// signal attach
ch <- struct{}{}
// wait for attach
<-ch
}
}
func (s *State) AddListener(jobID string) chan host.Event {
ch := make(chan host.Event)
s.listenMtx.Lock()
if _, ok := s.listeners[jobID]; !ok {
s.listeners[jobID] = make(map[chan host.Event]struct{})
}
s.listeners[jobID][ch] = struct{}{}
s.listenMtx.Unlock()
return ch
}
func (s *State) RemoveListener(jobID string, ch chan host.Event) {
go func() {
// drain to prevent deadlock while removing the listener
for range ch {
}
}()
s.listenMtx.Lock()
delete(s.listeners[jobID], ch)
if len(s.listeners[jobID]) == 0 {
delete(s.listeners, jobID)
}
s.listenMtx.Unlock()
close(ch)
}
func (s *State) sendEvent(job *host.ActiveJob, event string) {
j := job.Dup()
go func() {
s.listenMtx.RLock()
defer s.listenMtx.RUnlock()
e := host.Event{JobID: job.Job.ID, Job: j, Event: event}
for ch := range s.listeners["all"] {
ch <- e
}
for ch := range s.listeners[job.Job.ID] {
ch <- e
}
}()
}
func (s *State) SetPersistentSlot(slot string, jobID string) error {
if err := s.Acquire(); err != nil {
return err
}
defer s.Release()
return s.stateDB.Update(func(tx *bolt.Tx) error {
persistentBucket := tx.Bucket([]byte("persistent-jobs"))
return persistentBucket.Put([]byte(slot), []byte(jobID))
})
}