hnakra/service/service.go

92 lines
2.5 KiB
Go

// Package service provides a toolkit for creating Hnakra services.
package service
import "os"
import "log"
import "time"
import "hnakra/rotate"
import "hnakra/daemon"
import "hnakra/routines"
// Service is capable of managing multiple mounts. It also sets up logging
// automatically.
type Service struct {
ServiceInfo
Mounts []Mount
manager routines.Manager
}
// NewService provides a shorthand for creating a new service, leaving most
// values to their default.
func NewService (name, description string, mounts ...Mount) *Service {
return &Service {
ServiceInfo: ServiceInfo {
Name: name,
Description: description,
},
Mounts: mounts,
}
}
// Run runs the mounts within the service, and only exits when all of them have
// exited. It will automatically start logging to the directory specified by
// $HNAKRA_LOG_DIR. If that variable is unset, it will just log to stdout.
// Additionally, if $HNAKRA_PIDFILE is set, it will write the process PID to the
// file specified by it.
func (service *Service) Run () error {
// set up logging
logDir := os.Getenv("HNAKRA_LOG_DIR")
if logDir != "" {
logger, err := rotate.New(logDir)
if err != nil { log.Fatal("cannot access log dir:", err) }
log.SetOutput(logger)
}
log.Println("... starting service", service.Name)
// set up routine manager
service.manager = routines.Manager { RestartDeadline: time.Second * 8 }
service.manager.Routines = make([]routines.Routine, len(service.Mounts))
for index, mount := range service.Mounts {
service.manager.Routines[index] = routines.From (func () error {
return mount.Run(service.ServiceInfo)
}, mount.Shutdown)
}
// be a daemon
daemon.ShutdownOnSigint(service)
pidfile := daemon.PidFile(os.Getenv("HNAKRA_PIDFILE"))
if !pidfile.Empty() {
err := pidfile.Start()
if err != nil { log.Println("!!! could not write pid:", err) }
defer func () {
err := pidfile.Close()
if err != nil { log.Println("!!! could not delete pidfile:", err) }
} ()
}
// send it
err := service.manager.Run()
if err != nil { log.Println("XXX", err) }
return err
}
// Close abruptly closes all mounts in the service. This will cause Run() to
// exit.
func (service *Service) Close () (err error) {
for _, mount := range service.Mounts {
singleErr := mount.Close()
if singleErr != nil {
err = singleErr
}
}
return
}
// Shutdown gracefully shuts down each mount in the service. This will cause
// Run() to exit.
func (service *Service) Shutdown () (err error) {
return service.manager.Shutdown()
}