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supervise: refactor to use one HTTP handler

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This commit is contained in:
Michael Stapelberg 2018-06-25 18:27:23 +02:00
parent 9a14ab0d8d
commit 7dc7a36757
1 changed files with 85 additions and 97 deletions
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182
supervise.go
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@ -105,6 +105,15 @@ func (s *service) Process() *os.Process {
return s.process
}
func (s *service) Signal(signal syscall.Signal) error {
s.processMu.RLock()
defer s.processMu.RUnlock()
if s.process != nil {
return s.process.Signal(signal)
}
return nil // no process, nothing to signal
}
func (s *service) setProcess(p *os.Process) {
s.processMu.Lock()
defer s.processMu.Unlock()
@ -195,7 +204,78 @@ func supervise(s *service) {
}
}
func redirectToStatus(w http.ResponseWriter, r *http.Request, path string) {
var services []*service
// killSupervisedServices is called before rebooting when upgrading, allowing
// processes to terminate in an orderly fashion.
func killSupervisedServices() {
for _, s := range services {
if s.Stopped() {
continue
}
s.setStopped(true)
if p := s.Process(); p != nil {
p.Signal(syscall.SIGTERM)
}
}
}
func findSvc(path string) *service {
for _, s := range services {
if s.cmd.Path == path {
return s
}
}
return nil
}
func restart(s *service, signal syscall.Signal) error {
if s.Stopped() {
s.setStopped(false) // start process in next supervise iteration
return nil
}
return s.Signal(signal) // kill to restart
}
func stop(s *service, signal syscall.Signal) error {
if s.Stopped() {
return nil // nothing to do
}
s.setStopped(true)
return s.Signal(signal)
}
func stopstartHandler(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodPost {
http.Error(w, "expected a POST request", http.StatusBadRequest)
return
}
signal := syscall.SIGTERM
if r.FormValue("signal") == "kill" {
signal = syscall.SIGKILL
}
path := r.FormValue("path")
s := findSvc(path)
if s == nil {
http.Error(w, "no such service", http.StatusNotFound)
return
}
var err error
if r.URL.Path == "/restart" {
err = restart(s, signal)
} else {
err = stop(s, signal)
}
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
// StatusSeeOther will result in a GET request for the
// redirect location
u, _ := url.Parse("/status")
@ -205,104 +285,12 @@ func redirectToStatus(w http.ResponseWriter, r *http.Request, path string) {
http.Redirect(w, r, u.String(), http.StatusSeeOther)
}
// killSupervisedServices is called before rebooting when upgrading, allowing
// processes to terminate in an orderly fashion.
var killSupervisedServices = func() {}
func superviseServices(services []*service) {
func superviseServices(svc []*service) {
services = svc
for _, s := range services {
go supervise(s)
}
findSvc := func(path string) *service {
for _, s := range services {
if s.cmd.Path == path {
return s
}
}
return nil
}
killSupervisedServices = func() {
for _, s := range services {
if s.Stopped() {
continue
}
s.setStopped(true)
if p := s.Process(); p != nil {
p.Signal(syscall.SIGTERM)
}
}
}
http.HandleFunc("/stop", func(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodPost {
http.Error(w, "expected a POST request", http.StatusBadRequest)
return
}
path := r.FormValue("path")
s := findSvc(path)
if s == nil || s.Stopped() {
redirectToStatus(w, r, path)
return
}
s.setStopped(true)
p := s.Process()
if p == nil {
redirectToStatus(w, r, path)
return
}
if err := p.Signal(syscall.SIGTERM); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
redirectToStatus(w, r, path)
})
http.HandleFunc("/restart", func(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodPost {
http.Error(w, "expected a POST request", http.StatusBadRequest)
return
}
signal := syscall.SIGTERM
if r.FormValue("signal") == "kill" {
signal = syscall.SIGKILL
}
path := r.FormValue("path")
s := findSvc(path)
if s == nil {
redirectToStatus(w, r, path)
return
}
if s.Stopped() {
s.setStopped(false)
redirectToStatus(w, r, path)
return
}
p := s.Process()
if p == nil {
redirectToStatus(w, r, path)
return
}
if err := p.Signal(signal); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
redirectToStatus(w, r, path)
})
http.HandleFunc("/stop", stopstartHandler)
http.HandleFunc("/restart", stopstartHandler)
}