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