services/crunch-dispatch-local/crunch-dispatch-local.go

   1 package main
   2
   3 // Dispatcher service for Crunch that runs containers locally.
   4
   5 import (
   6         "flag"
   7         "git.curoverse.com/arvados.git/sdk/go/arvados"
   8         "git.curoverse.com/arvados.git/sdk/go/arvadosclient"
   9         "git.curoverse.com/arvados.git/sdk/go/dispatch"
  10         "log"
  11         "os"
  12         "os/exec"
  13         "os/signal"
  14         "sync"
  15         "syscall"
  16         "time"
  17 )
  18
  19 func main() {
  20         err := doMain()
  21         if err != nil {
  22                 log.Fatalf("%q", err)
  23         }
  24 }
  25
  26 var (
  27         runningCmds      map[string]*exec.Cmd
  28         runningCmdsMutex sync.Mutex
  29         waitGroup        sync.WaitGroup
  30         crunchRunCommand *string
  31 )
  32
  33 func doMain() error {
  34         flags := flag.NewFlagSet("crunch-dispatch-local", flag.ExitOnError)
  35
  36         pollInterval := flags.Int(
  37                 "poll-interval",
  38                 10,
  39                 "Interval in seconds to poll for queued containers")
  40
  41         crunchRunCommand = flags.String(
  42                 "crunch-run-command",
  43                 "/usr/bin/crunch-run",
  44                 "Crunch command to run container")
  45
  46         // Parse args; omit the first arg which is the command name
  47         flags.Parse(os.Args[1:])
  48
  49         runningCmds = make(map[string]*exec.Cmd)
  50
  51         arv, err := arvadosclient.MakeArvadosClient()
  52         if err != nil {
  53                 log.Printf("Error making Arvados client: %v", err)
  54                 return err
  55         }
  56         arv.Retries = 25
  57
  58         dispatcher := dispatch.Dispatcher{
  59                 Arv:          arv,
  60                 RunContainer: run,
  61                 PollPeriod:   time.Duration(*pollInterval) * time.Second,
  62         }
  63
  64         err = dispatcher.Run()
  65         if err != nil {
  66                 return err
  67         }
  68
  69         c := make(chan os.Signal, 1)
  70         signal.Notify(c, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
  71         sig := <-c
  72         log.Printf("Received %s, shutting down", sig)
  73         signal.Stop(c)
  74
  75         dispatcher.Stop()
  76
  77         runningCmdsMutex.Lock()
  78         // Finished dispatching; interrupt any crunch jobs that are still running
  79         for _, cmd := range runningCmds {
  80                 cmd.Process.Signal(os.Interrupt)
  81         }
  82         runningCmdsMutex.Unlock()
  83
  84         // Wait for all running crunch jobs to complete / terminate
  85         waitGroup.Wait()
  86
  87         return nil
  88 }
  89
  90 func startFunc(container arvados.Container, cmd *exec.Cmd) error {
  91         return cmd.Start()
  92 }
  93
  94 var startCmd = startFunc
  95
  96 // Run a container.
  97 //
  98 // If the container is Locked, start a new crunch-run process and wait until
  99 // crunch-run completes.  If the priority is set to zero, set an interrupt
 100 // signal to the crunch-run process.
 101 //
 102 // If the container is in any other state, or is not Complete/Cancelled after
 103 // crunch-run terminates, mark the container as Cancelled.
 104 func run(dispatcher *dispatch.Dispatcher,
 105         container arvados.Container,
 106         status chan arvados.Container) {
 107
 108         uuid := container.UUID
 109
 110         if container.State == dispatch.Locked {
 111                 waitGroup.Add(1)
 112
 113                 cmd := exec.Command(*crunchRunCommand, uuid)
 114                 cmd.Stdin = nil
 115                 cmd.Stderr = os.Stderr
 116                 cmd.Stdout = os.Stderr
 117
 118                 log.Printf("Starting container %v", uuid)
 119
 120                 // Add this crunch job to the list of runningCmds only if we
 121                 // succeed in starting crunch-run.
 122
 123                 runningCmdsMutex.Lock()
 124                 if err := startCmd(container, cmd); err != nil {
 125                         runningCmdsMutex.Unlock()
 126                         log.Printf("Error starting %v for %v: %q", *crunchRunCommand, uuid, err)
 127                         dispatcher.UpdateState(uuid, dispatch.Cancelled)
 128                 } else {
 129                         runningCmds[uuid] = cmd
 130                         runningCmdsMutex.Unlock()
 131
 132                         // Need to wait for crunch-run to exit
 133                         done := make(chan struct{})
 134
 135                         go func() {
 136                                 if _, err := cmd.Process.Wait(); err != nil {
 137                                         log.Printf("Error while waiting for crunch job to finish for %v: %q", uuid, err)
 138                                 }
 139                                 log.Printf("sending done")
 140                                 done <- struct{}{}
 141                         }()
 142
 143                 Loop:
 144                         for {
 145                                 select {
 146                                 case <-done:
 147                                         break Loop
 148                                 case c := <-status:
 149                                         // Interrupt the child process if priority changes to 0
 150                                         if (c.State == dispatch.Locked || c.State == dispatch.Running) && c.Priority == 0 {
 151                                                 log.Printf("Sending SIGINT to pid %d to cancel container %v", cmd.Process.Pid, uuid)
 152                                                 cmd.Process.Signal(os.Interrupt)
 153                                         }
 154                                 }
 155                         }
 156                         close(done)
 157
 158                         log.Printf("Finished container run for %v", uuid)
 159
 160                         // Remove the crunch job from runningCmds
 161                         runningCmdsMutex.Lock()
 162                         delete(runningCmds, uuid)
 163                         runningCmdsMutex.Unlock()
 164                 }
 165                 waitGroup.Done()
 166         }
 167
 168         // If the container is not finalized, then change it to "Cancelled".
 169         err := dispatcher.Arv.Get("containers", uuid, nil, &container)
 170         if err != nil {
 171                 log.Printf("Error getting final container state: %v", err)
 172         }
 173         if container.LockedByUUID == dispatcher.Auth.UUID &&
 174                 (container.State == dispatch.Locked || container.State == dispatch.Running) {
 175                 log.Printf("After %s process termination, container state for %v is %q.  Updating it to %q",
 176                         *crunchRunCommand, container.State, uuid, dispatch.Cancelled)
 177                 dispatcher.UpdateState(uuid, dispatch.Cancelled)
 178         }
 179
 180         // drain any subsequent status changes
 181         for range status {
 182         }
 183
 184         log.Printf("Finalized container %v", uuid)
 185 }