forked from Shiloh/githaven
7314726bab
The old process manager's `Trace` function by default calls `log.Printf` to output "trace" level logs. That's not ideal because by default the trace level logs should not be outputted. In history it didn't cause problems because there was no other call to the process manager before the logger system's initialization. But if there is any package using the process manager before the "Trace" function gets assigned to the logger system's trace function, the process manager will outputs unexpected verbose messages, this behavior is not expected in most cases. Now, the logger system also uses process manager to manage its goroutine contexts, so it's the time to fix the old "trace" behavior: by default, do not output the trace level messages. Fix #24951
244 lines
8.2 KiB
Go
244 lines
8.2 KiB
Go
// Copyright 2014 The Gogs Authors. All rights reserved.
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// Copyright 2019 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package process
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import (
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"context"
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"runtime/pprof"
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"strconv"
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"sync"
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"sync/atomic"
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"time"
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)
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// TODO: This packages still uses a singleton for the Manager.
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// Once there's a decent web framework and dependencies are passed around like they should,
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// then we delete the singleton.
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var (
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manager *Manager
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managerInit sync.Once
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// DefaultContext is the default context to run processing commands in
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DefaultContext = context.Background()
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)
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// DescriptionPProfLabel is a label set on goroutines that have a process attached
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const DescriptionPProfLabel = "process-description"
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// PIDPProfLabel is a label set on goroutines that have a process attached
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const PIDPProfLabel = "pid"
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// PPIDPProfLabel is a label set on goroutines that have a process attached
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const PPIDPProfLabel = "ppid"
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// ProcessTypePProfLabel is a label set on goroutines that have a process attached
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const ProcessTypePProfLabel = "process-type"
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// IDType is a pid type
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type IDType string
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// FinishedFunc is a function that marks that the process is finished and can be removed from the process table
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// - it is simply an alias for context.CancelFunc and is only for documentary purposes
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type FinishedFunc = context.CancelFunc
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var (
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traceDisabled atomic.Int64
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TraceCallback = defaultTraceCallback // this global can be overridden by particular logging packages - thus avoiding import cycles
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)
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// defaultTraceCallback is a no-op. Without a proper TraceCallback (provided by the logger system), this "Trace" level messages shouldn't be outputted.
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func defaultTraceCallback(skip int, start bool, pid IDType, description string, parentPID IDType, typ string) {
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}
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// TraceLogDisable disables (or revert the disabling) the trace log for the process lifecycle.
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// eg: the logger system shouldn't print the trace log for themselves, that's cycle dependency (Logger -> ProcessManager -> TraceCallback -> Logger ...)
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// Theoretically, such trace log should only be enabled when the logger system is ready with a proper level, so the default TraceCallback is a no-op.
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func TraceLogDisable(v bool) {
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if v {
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traceDisabled.Add(1)
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} else {
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traceDisabled.Add(-1)
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}
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}
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func Trace(start bool, pid IDType, description string, parentPID IDType, typ string) {
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if traceDisabled.Load() != 0 {
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// the traceDisabled counter is mainly for recursive calls, so no concurrency problem.
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// because the counter can't be 0 since the caller function hasn't returned (decreased the counter) yet.
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return
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}
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TraceCallback(1, start, pid, description, parentPID, typ)
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}
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// Manager manages all processes and counts PIDs.
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type Manager struct {
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mutex sync.Mutex
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next int64
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lastTime int64
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processMap map[IDType]*process
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}
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// GetManager returns a Manager and initializes one as singleton if there's none yet
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func GetManager() *Manager {
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managerInit.Do(func() {
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manager = &Manager{
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processMap: make(map[IDType]*process),
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next: 1,
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}
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})
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return manager
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}
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// AddContext creates a new context and adds it as a process. Once the process is finished, finished must be called
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// to remove the process from the process table. It should not be called until the process is finished but must always be called.
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//
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// cancel should be used to cancel the returned context, however it will not remove the process from the process table.
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// finished will cancel the returned context and remove it from the process table.
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//
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// 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
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// process table.
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func (pm *Manager) AddContext(parent context.Context, description string) (ctx context.Context, cancel context.CancelFunc, finished FinishedFunc) {
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ctx, cancel = context.WithCancel(parent)
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ctx, _, finished = pm.Add(ctx, description, cancel, NormalProcessType, true)
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return ctx, cancel, finished
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}
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// AddTypedContext creates a new context and adds it as a process. Once the process is finished, finished must be called
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// to remove the process from the process table. It should not be called until the process is finished but must always be called.
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//
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// cancel should be used to cancel the returned context, however it will not remove the process from the process table.
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// finished will cancel the returned context and remove it from the process table.
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//
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// 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
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// process table.
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func (pm *Manager) AddTypedContext(parent context.Context, description, processType string, currentlyRunning bool) (ctx context.Context, cancel context.CancelFunc, finished FinishedFunc) {
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ctx, cancel = context.WithCancel(parent)
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ctx, _, finished = pm.Add(ctx, description, cancel, processType, currentlyRunning)
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return ctx, cancel, finished
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}
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// AddContextTimeout creates a new context and add it as a process. Once the process is finished, finished must be called
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// to remove the process from the process table. It should not be called until the process is finished but must always be called.
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//
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// cancel should be used to cancel the returned context, however it will not remove the process from the process table.
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// finished will cancel the returned context and remove it from the process table.
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//
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// 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
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// process table.
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func (pm *Manager) AddContextTimeout(parent context.Context, timeout time.Duration, description string) (ctx context.Context, cancel context.CancelFunc, finshed FinishedFunc) {
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if timeout <= 0 {
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// 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
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panic("the timeout must be greater than zero, otherwise the context will be cancelled immediately")
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}
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ctx, cancel = context.WithTimeout(parent, timeout)
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ctx, _, finshed = pm.Add(ctx, description, cancel, NormalProcessType, true)
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return ctx, cancel, finshed
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}
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// Add create a new process
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func (pm *Manager) Add(ctx context.Context, description string, cancel context.CancelFunc, processType string, currentlyRunning bool) (context.Context, IDType, FinishedFunc) {
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parentPID := GetParentPID(ctx)
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pm.mutex.Lock()
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start, pid := pm.nextPID()
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parent := pm.processMap[parentPID]
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if parent == nil {
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parentPID = ""
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}
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process := &process{
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PID: pid,
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ParentPID: parentPID,
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Description: description,
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Start: start,
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Cancel: cancel,
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Type: processType,
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}
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var finished FinishedFunc
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if currentlyRunning {
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finished = func() {
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cancel()
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pm.remove(process)
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pprof.SetGoroutineLabels(ctx)
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}
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} else {
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finished = func() {
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cancel()
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pm.remove(process)
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}
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}
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pm.processMap[pid] = process
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pm.mutex.Unlock()
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Trace(true, pid, description, parentPID, processType)
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pprofCtx := pprof.WithLabels(ctx, pprof.Labels(DescriptionPProfLabel, description, PPIDPProfLabel, string(parentPID), PIDPProfLabel, string(pid), ProcessTypePProfLabel, processType))
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if currentlyRunning {
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pprof.SetGoroutineLabels(pprofCtx)
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}
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return &Context{
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Context: pprofCtx,
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pid: pid,
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}, pid, finished
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}
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// nextPID will return the next available PID. pm.mutex should already be locked.
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func (pm *Manager) nextPID() (start time.Time, pid IDType) {
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start = time.Now()
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startUnix := start.Unix()
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if pm.lastTime == startUnix {
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pm.next++
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} else {
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pm.next = 1
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}
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pm.lastTime = startUnix
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pid = IDType(strconv.FormatInt(start.Unix(), 16))
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if pm.next == 1 {
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return
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}
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pid = IDType(string(pid) + "-" + strconv.FormatInt(pm.next, 10))
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return start, pid
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}
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func (pm *Manager) remove(process *process) {
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deleted := false
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pm.mutex.Lock()
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if pm.processMap[process.PID] == process {
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delete(pm.processMap, process.PID)
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deleted = true
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}
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pm.mutex.Unlock()
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if deleted {
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Trace(false, process.PID, process.Description, process.ParentPID, process.Type)
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}
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}
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// Cancel a process in the ProcessManager.
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func (pm *Manager) Cancel(pid IDType) {
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pm.mutex.Lock()
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process, ok := pm.processMap[pid]
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pm.mutex.Unlock()
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if ok && process.Type != SystemProcessType {
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process.Cancel()
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}
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}
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