forgejo/modules/process/manager.go
wxiaoguang 18f26cfbf7
Improve queue and logger context (#24924)
Before there was a "graceful function": RunWithShutdownFns, it's mainly
for some modules which doesn't support context.

The old queue system doesn't work well with context, so the old queues
need it.

After the queue refactoring, the new queue works with context well, so,
use Golang context as much as possible, the `RunWithShutdownFns` could
be removed (replaced by RunWithCancel for context cancel mechanism), the
related code could be simplified.

This PR also fixes some legacy queue-init problems, eg:

* typo : archiver: "unable to create codes indexer queue" => "unable to
create repo-archive queue"
* no nil check for failed queues, which causes unfriendly panic

After this PR, many goroutines could have better display name:

![image](https://github.com/go-gitea/gitea/assets/2114189/701b2a9b-8065-4137-aeaa-0bda2b34604a)

![image](https://github.com/go-gitea/gitea/assets/2114189/f1d5f50f-0534-40f0-b0be-f2c9daa5fe92)
2023-05-26 07:31:55 +00:00

226 lines
7.4 KiB
Go

// Copyright 2014 The Gogs Authors. All rights reserved.
// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package process
import (
"context"
"log"
"runtime/pprof"
"strconv"
"sync"
"time"
)
// TODO: This packages still uses a singleton for the Manager.
// Once there's a decent web framework and dependencies are passed around like they should,
// then we delete the singleton.
var (
manager *Manager
managerInit sync.Once
// DefaultContext is the default context to run processing commands in
DefaultContext = context.Background()
)
// DescriptionPProfLabel is a label set on goroutines that have a process attached
const DescriptionPProfLabel = "process-description"
// PIDPProfLabel is a label set on goroutines that have a process attached
const PIDPProfLabel = "pid"
// PPIDPProfLabel is a label set on goroutines that have a process attached
const PPIDPProfLabel = "ppid"
// ProcessTypePProfLabel is a label set on goroutines that have a process attached
const ProcessTypePProfLabel = "process-type"
// IDType is a pid type
type IDType string
// FinishedFunc is a function that marks that the process is finished and can be removed from the process table
// - it is simply an alias for context.CancelFunc and is only for documentary purposes
type FinishedFunc = context.CancelFunc
var Trace = defaultTrace // this global can be overridden by particular logging packages - thus avoiding import cycles
func defaultTrace(start bool, pid IDType, description string, parentPID IDType, typ string) {
if start && parentPID != "" {
log.Printf("start process %s: %s (from %s) (%s)", pid, description, parentPID, typ)
} else if start {
log.Printf("start process %s: %s (%s)", pid, description, typ)
} else {
log.Printf("end process %s: %s", pid, description)
}
}
// Manager manages all processes and counts PIDs.
type Manager struct {
mutex sync.Mutex
next int64
lastTime int64
processMap map[IDType]*process
}
// GetManager returns a Manager and initializes one as singleton if there's none yet
func GetManager() *Manager {
managerInit.Do(func() {
manager = &Manager{
processMap: make(map[IDType]*process),
next: 1,
}
})
return manager
}
// AddContext creates a new context and adds it as a process. Once the process is finished, finished must be called
// to remove the process from the process table. It should not be called until the process is finished but must always be called.
//
// cancel should be used to cancel the returned context, however it will not remove the process from the process table.
// finished will cancel the returned context and remove it from the process table.
//
// Most processes will not need to use the cancel function but there will be cases whereby you want to cancel the process but not immediately remove it from the
// process table.
func (pm *Manager) AddContext(parent context.Context, description string) (ctx context.Context, cancel context.CancelFunc, finished FinishedFunc) {
ctx, cancel = context.WithCancel(parent)
ctx, _, finished = pm.Add(ctx, description, cancel, NormalProcessType, true)
return ctx, cancel, finished
}
// AddTypedContext creates a new context and adds it as a process. Once the process is finished, finished must be called
// to remove the process from the process table. It should not be called until the process is finished but must always be called.
//
// cancel should be used to cancel the returned context, however it will not remove the process from the process table.
// finished will cancel the returned context and remove it from the process table.
//
// Most processes will not need to use the cancel function but there will be cases whereby you want to cancel the process but not immediately remove it from the
// process table.
func (pm *Manager) AddTypedContext(parent context.Context, description, processType string, currentlyRunning bool) (ctx context.Context, cancel context.CancelFunc, finished FinishedFunc) {
ctx, cancel = context.WithCancel(parent)
ctx, _, finished = pm.Add(ctx, description, cancel, processType, currentlyRunning)
return ctx, cancel, finished
}
// AddContextTimeout creates a new context and add it as a process. Once the process is finished, finished must be called
// to remove the process from the process table. It should not be called until the process is finished but must always be called.
//
// cancel should be used to cancel the returned context, however it will not remove the process from the process table.
// finished will cancel the returned context and remove it from the process table.
//
// Most processes will not need to use the cancel function but there will be cases whereby you want to cancel the process but not immediately remove it from the
// process table.
func (pm *Manager) AddContextTimeout(parent context.Context, timeout time.Duration, description string) (ctx context.Context, cancel context.CancelFunc, finshed FinishedFunc) {
if timeout <= 0 {
// it's meaningless to use timeout <= 0, and it must be a bug! so we must panic here to tell developers to make the timeout correct
panic("the timeout must be greater than zero, otherwise the context will be cancelled immediately")
}
ctx, cancel = context.WithTimeout(parent, timeout)
ctx, _, finshed = pm.Add(ctx, description, cancel, NormalProcessType, true)
return ctx, cancel, finshed
}
// Add create a new process
func (pm *Manager) Add(ctx context.Context, description string, cancel context.CancelFunc, processType string, currentlyRunning bool) (context.Context, IDType, FinishedFunc) {
parentPID := GetParentPID(ctx)
pm.mutex.Lock()
start, pid := pm.nextPID()
parent := pm.processMap[parentPID]
if parent == nil {
parentPID = ""
}
process := &process{
PID: pid,
ParentPID: parentPID,
Description: description,
Start: start,
Cancel: cancel,
Type: processType,
}
var finished FinishedFunc
if currentlyRunning {
finished = func() {
cancel()
pm.remove(process)
pprof.SetGoroutineLabels(ctx)
}
} else {
finished = func() {
cancel()
pm.remove(process)
}
}
pm.processMap[pid] = process
pm.mutex.Unlock()
Trace(true, pid, description, parentPID, processType)
pprofCtx := pprof.WithLabels(ctx, pprof.Labels(DescriptionPProfLabel, description, PPIDPProfLabel, string(parentPID), PIDPProfLabel, string(pid), ProcessTypePProfLabel, processType))
if currentlyRunning {
pprof.SetGoroutineLabels(pprofCtx)
}
return &Context{
Context: pprofCtx,
pid: pid,
}, pid, finished
}
// nextPID will return the next available PID. pm.mutex should already be locked.
func (pm *Manager) nextPID() (start time.Time, pid IDType) {
start = time.Now()
startUnix := start.Unix()
if pm.lastTime == startUnix {
pm.next++
} else {
pm.next = 1
}
pm.lastTime = startUnix
pid = IDType(strconv.FormatInt(start.Unix(), 16))
if pm.next == 1 {
return
}
pid = IDType(string(pid) + "-" + strconv.FormatInt(pm.next, 10))
return start, pid
}
func (pm *Manager) remove(process *process) {
deleted := false
pm.mutex.Lock()
if pm.processMap[process.PID] == process {
delete(pm.processMap, process.PID)
deleted = true
}
pm.mutex.Unlock()
if deleted {
Trace(false, process.PID, process.Description, process.ParentPID, process.Type)
}
}
// Cancel a process in the ProcessManager.
func (pm *Manager) Cancel(pid IDType) {
pm.mutex.Lock()
process, ok := pm.processMap[pid]
pm.mutex.Unlock()
if ok && process.Type != SystemProcessType {
process.Cancel()
}
}