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

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package main
   6
   7 // Dispatcher service for Crunch that runs containers locally.
   8
   9 import (
  10         "context"
  11         "flag"
  12         "log"
  13         "os"
  14         "os/exec"
  15         "os/signal"
  16         "sync"
  17         "syscall"
  18         "time"
  19
  20         "git.curoverse.com/arvados.git/sdk/go/arvados"
  21         "git.curoverse.com/arvados.git/sdk/go/arvadosclient"
  22         "git.curoverse.com/arvados.git/sdk/go/dispatch"
  23 )
  24
  25 func main() {
  26         err := doMain()
  27         if err != nil {
  28                 log.Fatalf("%q", err)
  29         }
  30 }
  31
  32 var (
  33         runningCmds      map[string]*exec.Cmd
  34         runningCmdsMutex sync.Mutex
  35         waitGroup        sync.WaitGroup
  36         crunchRunCommand *string
  37 )
  38
  39 func doMain() error {
  40         flags := flag.NewFlagSet("crunch-dispatch-local", flag.ExitOnError)
  41
  42         pollInterval := flags.Int(
  43                 "poll-interval",
  44                 10,
  45                 "Interval in seconds to poll for queued containers")
  46
  47         crunchRunCommand = flags.String(
  48                 "crunch-run-command",
  49                 "/usr/bin/crunch-run",
  50                 "Crunch command to run container")
  51
  52         // Parse args; omit the first arg which is the command name
  53         flags.Parse(os.Args[1:])
  54
  55         runningCmds = make(map[string]*exec.Cmd)
  56
  57         arv, err := arvadosclient.MakeArvadosClient()
  58         if err != nil {
  59                 log.Printf("Error making Arvados client: %v", err)
  60                 return err
  61         }
  62         arv.Retries = 25
  63
  64         dispatcher := dispatch.Dispatcher{
  65                 Arv:          arv,
  66                 RunContainer: run,
  67                 PollPeriod:   time.Duration(*pollInterval) * time.Second,
  68         }
  69
  70         ctx, cancel := context.WithCancel(context.Background())
  71         err = dispatcher.Run(ctx)
  72         if err != nil {
  73                 return err
  74         }
  75
  76         c := make(chan os.Signal, 1)
  77         signal.Notify(c, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
  78         sig := <-c
  79         log.Printf("Received %s, shutting down", sig)
  80         signal.Stop(c)
  81
  82         cancel()
  83
  84         runningCmdsMutex.Lock()
  85         // Finished dispatching; interrupt any crunch jobs that are still running
  86         for _, cmd := range runningCmds {
  87                 cmd.Process.Signal(os.Interrupt)
  88         }
  89         runningCmdsMutex.Unlock()
  90
  91         // Wait for all running crunch jobs to complete / terminate
  92         waitGroup.Wait()
  93
  94         return nil
  95 }
  96
  97 func startFunc(container arvados.Container, cmd *exec.Cmd) error {
  98         return cmd.Start()
  99 }
 100
 101 var startCmd = startFunc
 102
 103 // Run a container.
 104 //
 105 // If the container is Locked, start a new crunch-run process and wait until
 106 // crunch-run completes.  If the priority is set to zero, set an interrupt
 107 // signal to the crunch-run process.
 108 //
 109 // If the container is in any other state, or is not Complete/Cancelled after
 110 // crunch-run terminates, mark the container as Cancelled.
 111 func run(dispatcher *dispatch.Dispatcher,
 112         container arvados.Container,
 113         status <-chan arvados.Container) {
 114
 115         uuid := container.UUID
 116
 117         if container.State == dispatch.Locked {
 118                 waitGroup.Add(1)
 119
 120                 cmd := exec.Command(*crunchRunCommand, uuid)
 121                 cmd.Stdin = nil
 122                 cmd.Stderr = os.Stderr
 123                 cmd.Stdout = os.Stderr
 124
 125                 log.Printf("Starting container %v", uuid)
 126
 127                 // Add this crunch job to the list of runningCmds only if we
 128                 // succeed in starting crunch-run.
 129
 130                 runningCmdsMutex.Lock()
 131                 if err := startCmd(container, cmd); err != nil {
 132                         runningCmdsMutex.Unlock()
 133                         log.Printf("Error starting %v for %v: %q", *crunchRunCommand, uuid, err)
 134                         dispatcher.UpdateState(uuid, dispatch.Cancelled)
 135                 } else {
 136                         runningCmds[uuid] = cmd
 137                         runningCmdsMutex.Unlock()
 138
 139                         // Need to wait for crunch-run to exit
 140                         done := make(chan struct{})
 141
 142                         go func() {
 143                                 if _, err := cmd.Process.Wait(); err != nil {
 144                                         log.Printf("Error while waiting for crunch job to finish for %v: %q", uuid, err)
 145                                 }
 146                                 log.Printf("sending done")
 147                                 done <- struct{}{}
 148                         }()
 149
 150                 Loop:
 151                         for {
 152                                 select {
 153                                 case <-done:
 154                                         break Loop
 155                                 case c := <-status:
 156                                         // Interrupt the child process if priority changes to 0
 157                                         if (c.State == dispatch.Locked || c.State == dispatch.Running) && c.Priority == 0 {
 158                                                 log.Printf("Sending SIGINT to pid %d to cancel container %v", cmd.Process.Pid, uuid)
 159                                                 cmd.Process.Signal(os.Interrupt)
 160                                         }
 161                                 }
 162                         }
 163                         close(done)
 164
 165                         log.Printf("Finished container run for %v", uuid)
 166
 167                         // Remove the crunch job from runningCmds
 168                         runningCmdsMutex.Lock()
 169                         delete(runningCmds, uuid)
 170                         runningCmdsMutex.Unlock()
 171                 }
 172                 waitGroup.Done()
 173         }
 174
 175         // If the container is not finalized, then change it to "Cancelled".
 176         err := dispatcher.Arv.Get("containers", uuid, nil, &container)
 177         if err != nil {
 178                 log.Printf("Error getting final container state: %v", err)
 179         }
 180         if container.State == dispatch.Locked || container.State == dispatch.Running {
 181                 log.Printf("After %s process termination, container state for %v is %q.  Updating it to %q",
 182                         *crunchRunCommand, container.State, uuid, dispatch.Cancelled)
 183                 dispatcher.UpdateState(uuid, dispatch.Cancelled)
 184         }
 185
 186         // drain any subsequent status changes
 187         for range status {
 188         }
 189
 190         log.Printf("Finalized container %v", uuid)
 191 }