lotus/lib/harmony/harmonytask/harmonytask.go
2023-11-15 13:06:00 +01:00

303 lines
9.5 KiB
Go

package harmonytask
import (
"context"
"fmt"
"strconv"
"sync/atomic"
"time"
"github.com/filecoin-project/lotus/lib/harmony/harmonydb"
"github.com/filecoin-project/lotus/lib/harmony/resources"
)
// Consts (except for unit test)
var POLL_DURATION = time.Second * 3 // Poll for Work this frequently
var CLEANUP_FREQUENCY = 5 * time.Minute // Check for dead workers this often * everyone
var FOLLOW_FREQUENCY = 1 * time.Minute // Check for work to follow this often
type TaskTypeDetails struct {
// Max returns how many tasks this machine can run of this type.
// Zero (default) or less means unrestricted.
Max int
// Name is the task name to be added to the task list.
Name string
// Peak costs to Do() the task.
Cost resources.Resources
// Max Failure count before the job is dropped.
// 0 = retry forever
MaxFailures uint
// Follow another task's completion via this task's creation.
// The function should populate extraInfo from data
// available from the previous task's tables, using the given TaskID.
// It should also return success if the trigger succeeded.
// NOTE: if refatoring tasks, see if your task is
// necessary. Ex: Is the sector state correct for your stage to run?
Follows map[string]func(TaskID, AddTaskFunc) (bool, error)
}
// TaskInterface must be implemented in order to have a task used by harmonytask.
type TaskInterface interface {
// Do the task assigned. Call stillOwned before making single-writer-only
// changes to ensure the work has not been stolen.
// This is the ONLY function that should attempt to do the work, and must
// ONLY be called by harmonytask.
// Indicate if the task no-longer needs scheduling with done=true including
// cases where it's past the deadline.
Do(taskID TaskID, stillOwned func() bool) (done bool, err error)
// CanAccept should return if the task can run on this machine. It should
// return null if the task type is not allowed on this machine.
// It should select the task it most wants to accomplish.
// It is also responsible for determining & reserving disk space (including scratch).
CanAccept([]TaskID, *TaskEngine) (*TaskID, error)
// TypeDetails() returns static details about how this task behaves and
// how this machine will run it. Read once at the beginning.
TypeDetails() TaskTypeDetails
// This listener will consume all external sources continuously for work.
// Do() may also be called from a backlog of work. This must not
// start doing the work (it still must be scheduled).
// Note: Task de-duplication should happen in ExtraInfoFunc by
// returning false, typically by determining from the tx that the work
// exists already. The easy way is to have a unique joint index
// across all fields that will be common.
// Adder should typically only add its own task type, but multiple
// is possible for when 1 trigger starts 2 things.
// Usage Example:
// func (b *BazType)Adder(addTask AddTaskFunc) {
// for {
// bazMaker := <- bazChannel
// addTask("baz", func(t harmonytask.TaskID, txn db.Transaction) (bool, error) {
// _, err := txn.Exec(`INSERT INTO bazInfoTable (taskID, qix, mot)
// VALUES ($1,$2,$3)`, id, bazMaker.qix, bazMaker.mot)
// if err != nil {
// scream(err)
// return false
// }
// return true
// })
// }
// }
Adder(AddTaskFunc)
}
// AddTaskFunc is responsible for adding a task's details "extra info" to the DB.
// It should return true if the task should be added, false if it was already there.
// This is typically accomplished with a "unique" index on your detals table that
// would cause the insert to fail.
// The error indicates that instead of a conflict (which we should ignore) that we
// actually have a serious problem that needs to be logged with context.
type AddTaskFunc func(extraInfo func(TaskID, *harmonydb.Tx) (shouldCommit bool, seriousError error))
type TaskEngine struct {
ctx context.Context
handlers []*taskTypeHandler
db *harmonydb.DB
reg *resources.Reg
grace context.CancelFunc
taskMap map[string]*taskTypeHandler
ownerID int
follows map[string][]followStruct
lastFollowTime time.Time
lastCleanup atomic.Value
hostAndPort string
}
type followStruct struct {
f func(TaskID, AddTaskFunc) (bool, error)
h *taskTypeHandler
name string
}
type TaskID int
// New creates all the task definitions. Note that TaskEngine
// knows nothing about the tasks themselves and serves to be a
// generic container for common work
func New(
db *harmonydb.DB,
impls []TaskInterface,
hostnameAndPort string) (*TaskEngine, error) {
reg, err := resources.Register(db, hostnameAndPort)
if err != nil {
return nil, fmt.Errorf("cannot get resources: %w", err)
}
ctx, grace := context.WithCancel(context.Background())
e := &TaskEngine{
ctx: ctx,
grace: grace,
db: db,
reg: reg,
ownerID: reg.Resources.MachineID, // The current number representing "hostAndPort"
taskMap: make(map[string]*taskTypeHandler, len(impls)),
follows: make(map[string][]followStruct),
hostAndPort: hostnameAndPort,
}
e.lastCleanup.Store(time.Now())
for _, c := range impls {
h := taskTypeHandler{
TaskInterface: c,
TaskTypeDetails: c.TypeDetails(),
TaskEngine: e,
}
e.handlers = append(e.handlers, &h)
e.taskMap[h.TaskTypeDetails.Name] = &h
}
// resurrect old work
{
var taskRet []struct {
ID int
Name string
}
err := db.Select(e.ctx, &taskRet, `SELECT id, name from harmony_task WHERE owner_id=$1`, e.ownerID)
if err != nil {
return nil, err
}
for _, w := range taskRet {
// edge-case: if old assignments are not available tasks, unlock them.
h := e.taskMap[w.Name]
if h == nil {
_, err := db.Exec(e.ctx, `UPDATE harmony_task SET owner=NULL WHERE id=$1`, w.ID)
if err != nil {
log.Errorw("Cannot remove self from owner field", "error", err)
continue // not really fatal, but not great
}
}
if !h.considerWork("recovered", []TaskID{TaskID(w.ID)}) {
log.Error("Strange: Unable to accept previously owned task: ", w.ID, w.Name)
}
}
}
for _, h := range e.handlers {
go h.Adder(h.AddTask)
}
go e.poller()
return e, nil
}
// GracefullyTerminate hangs until all present tasks have completed.
// Call this to cleanly exit the process. As some processes are long-running,
// passing a deadline will ignore those still running (to be picked-up later).
func (e *TaskEngine) GracefullyTerminate(deadline time.Duration) {
e.grace()
e.reg.Shutdown()
deadlineChan := time.NewTimer(deadline).C
top:
for _, h := range e.handlers {
if h.Count.Load() > 0 {
select {
case <-deadlineChan:
return
default:
time.Sleep(time.Millisecond)
goto top
}
}
}
}
func (e *TaskEngine) poller() {
for {
select {
case <-time.NewTicker(POLL_DURATION).C: // Find work periodically
case <-e.ctx.Done(): ///////////////////// Graceful exit
return
}
e.pollerTryAllWork()
if time.Since(e.lastFollowTime) > FOLLOW_FREQUENCY {
e.followWorkInDB()
}
}
}
// followWorkInDB implements "Follows"
func (e *TaskEngine) followWorkInDB() {
// Step 1: What are we following?
var lastFollowTime time.Time
lastFollowTime, e.lastFollowTime = e.lastFollowTime, time.Now()
for fromName, srcs := range e.follows {
var cList []int // Which work is done (that we follow) since we last checked?
err := e.db.Select(e.ctx, &cList, `SELECT h.task_id FROM harmony_task_history
WHERE h.work_end>$1 AND h.name=$2`, lastFollowTime, fromName)
if err != nil {
log.Error("Could not query DB: ", err)
return
}
for _, src := range srcs {
for _, workAlreadyDone := range cList { // Were any tasks made to follow these tasks?
var ct int
err := e.db.QueryRow(e.ctx, `SELECT COUNT(*) FROM harmony_task
WHERE name=$1 AND previous_task=$2`, src.h.Name, workAlreadyDone).Scan(&ct)
if err != nil {
log.Error("Could not query harmony_task: ", err)
return // not recoverable here
}
if ct > 0 {
continue
}
// we need to create this task
b, err := src.h.Follows[fromName](TaskID(workAlreadyDone), src.h.AddTask)
if err != nil {
log.Errorw("Could not follow: ", "error", err)
continue
}
if !b {
// But someone may have beaten us to it.
log.Debugf("Unable to add task %s following Task(%d, %s)", src.h.Name, workAlreadyDone, fromName)
}
}
}
}
}
// pollerTryAllWork starts the next 1 task
func (e *TaskEngine) pollerTryAllWork() {
if time.Since(e.lastCleanup.Load().(time.Time)) > CLEANUP_FREQUENCY {
e.lastCleanup.Store(time.Now())
resources.CleanupMachines(e.ctx, e.db)
}
for _, v := range e.handlers {
if v.AssertMachineHasCapacity() != nil {
continue
}
var unownedTasks []TaskID
err := e.db.Select(e.ctx, &unownedTasks, `SELECT id
FROM harmony_task
WHERE owner_id IS NULL AND name=$1
ORDER BY update_time`, v.Name)
if err != nil {
log.Error("Unable to read work ", err)
continue
}
if len(unownedTasks) > 0 {
accepted := v.considerWork("poller", unownedTasks)
if accepted {
return // accept new work slowly and in priority order
}
log.Warn("Work not accepted for " + strconv.Itoa(len(unownedTasks)) + " " + v.Name + " task(s)")
}
}
}
// ResourcesAvailable determines what resources are still unassigned.
func (e *TaskEngine) ResourcesAvailable() resources.Resources {
tmp := e.reg.Resources
for _, t := range e.handlers {
ct := t.Count.Load()
tmp.Cpu -= int(ct) * t.Cost.Cpu
tmp.Gpu -= float64(ct) * t.Cost.Gpu
tmp.Ram -= uint64(ct) * t.Cost.Ram
}
return tmp
}