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         "context"
   7         "flag"
   8         "log"
   9         "os"
  10         "os/exec"
  11         "os/signal"
  12         "sync"
  13         "syscall"
  14         "time"
  15
  16         "git.curoverse.com/arvados.git/sdk/go/arvados"
  17         "git.curoverse.com/arvados.git/sdk/go/arvadosclient"
  18         "git.curoverse.com/arvados.git/sdk/go/dispatch"
  19 )
  20
  21 func main() {
  22         err := doMain()
  23         if err != nil {
  24                 log.Fatalf("%q", err)
  25         }
  26 }
  27
  28 var (
  29         runningCmds      map[string]*exec.Cmd
  30         runningCmdsMutex sync.Mutex
  31         waitGroup        sync.WaitGroup
  32         crunchRunCommand *string
  33 )
  34
  35 func doMain() error {
  36         flags := flag.NewFlagSet("crunch-dispatch-local", flag.ExitOnError)
  37
  38         pollInterval := flags.Int(
  39                 "poll-interval",
  40                 10,
  41                 "Interval in seconds to poll for queued containers")
  42
  43         crunchRunCommand = flags.String(
  44                 "crunch-run-command",
  45                 "/usr/bin/crunch-run",
  46                 "Crunch command to run container")
  47
  48         // Parse args; omit the first arg which is the command name
  49         flags.Parse(os.Args[1:])
  50
  51         runningCmds = make(map[string]*exec.Cmd)
  52
  53         arv, err := arvadosclient.MakeArvadosClient()
  54         if err != nil {
  55                 log.Printf("Error making Arvados client: %v", err)
  56                 return err
  57         }
  58         arv.Retries = 25
  59
  60         dispatcher := dispatch.Dispatcher{
  61                 Arv:          arv,
  62                 RunContainer: run,
  63                 PollPeriod:   time.Duration(*pollInterval) * time.Second,
  64         }
  65
  66         ctx, cancel := context.WithCancel(context.Background())
  67         err = dispatcher.Run(ctx)
  68         if err != nil {
  69                 return err
  70         }
  71
  72         c := make(chan os.Signal, 1)
  73         signal.Notify(c, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
  74         sig := <-c
  75         log.Printf("Received %s, shutting down", sig)
  76         signal.Stop(c)
  77
  78         cancel()
  79
  80         runningCmdsMutex.Lock()
  81         // Finished dispatching; interrupt any crunch jobs that are still running
  82         for _, cmd := range runningCmds {
  83                 cmd.Process.Signal(os.Interrupt)
  84         }
  85         runningCmdsMutex.Unlock()
  86
  87         // Wait for all running crunch jobs to complete / terminate
  88         waitGroup.Wait()
  89
  90         return nil
  91 }
  92
  93 func startFunc(container arvados.Container, cmd *exec.Cmd) error {
  94         return cmd.Start()
  95 }
  96
  97 var startCmd = startFunc
  98
  99 // Run a container.
 100 //
 101 // If the container is Locked, start a new crunch-run process and wait until
 102 // crunch-run completes.  If the priority is set to zero, set an interrupt
 103 // signal to the crunch-run process.
 104 //
 105 // If the container is in any other state, or is not Complete/Cancelled after
 106 // crunch-run terminates, mark the container as Cancelled.
 107 func run(dispatcher *dispatch.Dispatcher,
 108         container arvados.Container,
 109         status <-chan arvados.Container) {
 110
 111         uuid := container.UUID
 112
 113         if container.State == dispatch.Locked {
 114                 waitGroup.Add(1)
 115
 116                 cmd := exec.Command(*crunchRunCommand, uuid)
 117                 cmd.Stdin = nil
 118                 cmd.Stderr = os.Stderr
 119                 cmd.Stdout = os.Stderr
 120
 121                 log.Printf("Starting container %v", uuid)
 122
 123                 // Add this crunch job to the list of runningCmds only if we
 124                 // succeed in starting crunch-run.
 125
 126                 runningCmdsMutex.Lock()
 127                 if err := startCmd(container, cmd); err != nil {
 128                         runningCmdsMutex.Unlock()
 129                         log.Printf("Error starting %v for %v: %q", *crunchRunCommand, uuid, err)
 130                         dispatcher.UpdateState(uuid, dispatch.Cancelled)
 131                 } else {
 132                         runningCmds[uuid] = cmd
 133                         runningCmdsMutex.Unlock()
 134
 135                         // Need to wait for crunch-run to exit
 136                         done := make(chan struct{})
 137
 138                         go func() {
 139                                 if _, err := cmd.Process.Wait(); err != nil {
 140                                         log.Printf("Error while waiting for crunch job to finish for %v: %q", uuid, err)
 141                                 }
 142                                 log.Printf("sending done")
 143                                 done <- struct{}{}
 144                         }()
 145
 146                 Loop:
 147                         for {
 148                                 select {
 149                                 case <-done:
 150                                         break Loop
 151                                 case c := <-status:
 152                                         // Interrupt the child process if priority changes to 0
 153                                         if (c.State == dispatch.Locked || c.State == dispatch.Running) && c.Priority == 0 {
 154                                                 log.Printf("Sending SIGINT to pid %d to cancel container %v", cmd.Process.Pid, uuid)
 155                                                 cmd.Process.Signal(os.Interrupt)
 156                                         }
 157                                 }
 158                         }
 159                         close(done)
 160
 161                         log.Printf("Finished container run for %v", uuid)
 162
 163                         // Remove the crunch job from runningCmds
 164                         runningCmdsMutex.Lock()
 165                         delete(runningCmds, uuid)
 166                         runningCmdsMutex.Unlock()
 167                 }
 168                 waitGroup.Done()
 169         }
 170
 171         // If the container is not finalized, then change it to "Cancelled".
 172         err := dispatcher.Arv.Get("containers", uuid, nil, &container)
 173         if err != nil {
 174                 log.Printf("Error getting final container state: %v", err)
 175         }
 176         if container.State == dispatch.Locked || container.State == dispatch.Running {
 177                 log.Printf("After %s process termination, container state for %v is %q.  Updating it to %q",
 178                         *crunchRunCommand, container.State, uuid, dispatch.Cancelled)
 179                 dispatcher.UpdateState(uuid, dispatch.Cancelled)
 180         }
 181
 182         // drain any subsequent status changes
 183         for range status {
 184         }
 185
 186         log.Printf("Finalized container %v", uuid)
 187 }