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