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status.go
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status.go
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package sarah
import (
"github.com/oklahomer/go-sarah/v2/log"
"golang.org/x/xerrors"
"sync"
)
var runnerStatus = &status{}
// ErrRunnerAlreadyRunning indicates that sarah.Run() is already called and the process is already running.
// When this is returned, a second or later activations are prevented so the initially activated process is still protected.
var ErrRunnerAlreadyRunning = xerrors.New("go-sarah's process is already running")
// CurrentStatus returns the current status of go-sarah.
// This can still be called even if sarah.Run() is not called, yet.
// So developers can safely build two different goroutines:
//
// - One to setup bot configuration and call sarah.Run()
// - Another to periodically call sarah.CurrentStatus() and monitor status.
// When Status.Running is false and Status.Bots is empty, then bot is not initiated yet.
func CurrentStatus() Status {
return runnerStatus.snapshot()
}
// Status represents the current status of the bot system including Runner and all registered Bots.
type Status struct {
Running bool
Bots []BotStatus
}
// BotStatus represents the current status of a Bot.
type BotStatus struct {
Type BotType
Running bool
}
type status struct {
bots []*botStatus
finished chan struct{}
mutex sync.RWMutex
}
func (s *status) running() bool {
s.mutex.RLock()
defer s.mutex.RUnlock()
finished := s.finished
if finished == nil {
// NewRunner() is called, status instance is created, but Runner.Run() is not called yet.
// This channel field is populated when status.start() is called via Runner.Run().
return false
}
select {
case <-finished:
return false
default:
return true
}
}
func (s *status) start() error {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.finished != nil {
return ErrRunnerAlreadyRunning
}
s.finished = make(chan struct{})
return nil
}
func (s *status) addBot(bot Bot) {
s.mutex.Lock()
defer s.mutex.Unlock()
botStatus := &botStatus{
botType: bot.BotType(),
finished: make(chan struct{}),
}
s.bots = append(s.bots, botStatus)
}
func (s *status) stopBot(bot Bot) {
s.mutex.RLock()
defer s.mutex.RUnlock()
for _, bs := range s.bots {
if bs.botType == bot.BotType() {
bs.stop()
}
}
}
func (s *status) snapshot() Status {
s.mutex.RLock()
defer s.mutex.RUnlock()
var bots []BotStatus
for _, botStatus := range s.bots {
bs := BotStatus{
Type: botStatus.botType,
Running: botStatus.running(),
}
bots = append(bots, bs)
}
return Status{
Running: s.running(),
Bots: bots,
}
}
func (s *status) stop() {
defer func() {
if recover() != nil {
// O.K.
// Comes here when channel is already closed.
// stop() is not expected to be called multiple times,
// but recover here to avoid panic.
log.Warn("Multiple status.stop() calls occurred.")
}
}()
close(s.finished)
}
type botStatus struct {
botType BotType
finished chan struct{}
}
func (bs *botStatus) running() bool {
select {
case <-bs.finished:
return false
default:
return true
}
}
func (bs *botStatus) stop() {
defer func() {
if recover() != nil {
// O.K.
// Comes here when channel is already closed.
// stop() is not expected to be called multiple times,
// but recover here to avoid panic.
log.Warnf("Multiple botStatus.stop() calls for %s occurred.", bs.botType)
}
}()
close(bs.finished)
}