Run a one-shot job on Docker Swarm Mode

Dockerfile

FROM golang:1.7.3
RUN mkdir -p /go/src/github.com/alexellis2/jaas
WORKDIR /go/src/github.com/alexellis2/jaas
COPY ./app.go ./

RUN go get -v -d
RUN go build

example.log

# Run service, block until complete. Check output of container:

alexr:jaas alex$ go build && ./jaas -image alexellis2/cows:latest
Service created: bumoso47nxfq8jr7tbqt7hi1q
ID:  bumoso47nxfq8jr7tbqt7hi1q State:  2016-12-19 01:48:58.414268594 +0000 UTC
.....................

0
complete
alexr:jaas alex$ docker service ps bumoso47nxfq8jr7tbqt7hi1q
ID                         NAME            IMAGE                   NODE  DESIRED STATE  CURRENT STATE         ERROR
d8ywqcdl90pi8yr0s09opbo0e  stoic_leakey.1  alexellis2/cows:latest  moby  Shutdown       Complete 7 hours ago  
alexr:jaas alex$ docker ps -a
CONTAINER ID        IMAGE                      COMMAND              CREATED             STATUS                      PORTS               NAMES
0eb6558b8ada        alexellis2/cows:latest     "node show_cow.js"   7 hours ago         Exited (0) 19 seconds ago                       stoic_leakey.1.d8ywqcdl90pi8yr0s09opbo0e
7cd7cd320e2e        alexellis2/gotask:latest   "./gotask"           7 hours ago         Exited (0) 3 minutes ago                        pensive_yalow.1.d7d700430bgy3hhh1b07hhobk
25f8cf37cd90        alexellis2/gotask:latest   "./gotask"           7 hours ago         Exited (0) 3 minutes ago                        evil_volhard.1.a5q3l2pgyhykouh7zvszuvqog
alexr:jaas alex$ docker logs 0eb
               __//     \__
       /^^^)^^/   )     (   \^^(^^^\
      /(    _(  ^/       \^  )_    )\
     /  \ //  | /         \ |  \ /  \
    /    \   O/           \O   //    \
   (    )/\                   //\(    )
   /\  //                         \  /\
  / / /W          COW-TOW          W\ \ \
*  \(                               )/  *
     \_                           _//
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
alexr:jaas alex$ 


# With a timeout

alexr:jaas alex$ go build && ./jaas -image alexellis2/gotask:latest -timeout 4
Service created: 2t88b04zou8aawbvtu8y1m9nk
ID:  2t88b04zou8aawbvtu8y1m9nk State:  2016-12-19 01:46:17.107590238 +0000 UTC
....Timing out after 4 ticks.
alexr:jaas alex$ 

jaas.go

package main

import (
	"flag"
	"fmt"
	"log"
	"time"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/filters"
	"github.com/docker/docker/api/types/swarm"
	"github.com/docker/docker/client"

	"io/ioutil"

	"golang.org/x/net/context"
)

// Enable Docker's experimental mode in 1.13-rc before continuing.
func main() {
	var image string
	var timeout int

	flag.StringVar(&image, "image", "", "Docker image name")
	flag.IntVar(&timeout, "timeout", 0, "ticks until we time out the service")
	flag.Parse()

	if len(image) == 0 {
		fmt.Println("Provide an image name")
		return
	}

	var c *client.Client
	var err error
	c, err = client.NewEnvClient()
	if err != nil {
		log.Fatal("Error with Docker client.")
	}

	spec := makeSpec(image)
	createOptions := types.ServiceCreateOptions{}
	createResponse, _ := c.ServiceCreate(context.Background(), spec, createOptions)
	fmt.Printf("Service created: %s\n", createResponse.ID)

	dump(c, createResponse.ID, timeout)
}

func makeSpec(image string) swarm.ServiceSpec {
	max := uint64(1)
	spec := swarm.ServiceSpec{
		TaskTemplate: swarm.TaskSpec{
			RestartPolicy: &swarm.RestartPolicy{
				MaxAttempts: &max,
				Condition:   swarm.RestartPolicyConditionNone,
			},
			ContainerSpec: swarm.ContainerSpec{
				Image: image,
			},
		},
	}
	return spec
}

func dump(c *client.Client, id string, timeout int) {
	filters2 := filters.NewArgs()
	filters2.Add("id", id)

	opts := types.ServiceListOptions{
		Filters: filters2,
	}

	list, _ := c.ServiceList(context.Background(), opts)
	for _, item := range list {
		ticks := 0
		fmt.Println("ID: ", item.ID, "State: ", item.UpdatedAt)
		for {
			time.Sleep(500 * time.Millisecond)
			ticks++
			if showTasks(c, item.ID) {
				return
			}

			if timeout > 0 && ticks >= timeout {
				fmt.Printf("Timing out after %d ticks.", ticks)
				return
			}
		}
	}
}

func showTasks(c *client.Client, id string) bool {
	filters1 := filters.NewArgs()
	filters1.Add("service", id)
	// fmt.Println("Task filter: ", id)
	val, _ := c.TaskList(context.Background(), types.TaskListOptions{
		Filters: filters1,
	})

	var done bool
	for _, v := range val {
		if v.Status.State == swarm.TaskStateComplete {
			fmt.Println("\n")
			fmt.Println(v.Status.ContainerStatus.ExitCode)
			fmt.Println(v.Status.State)

			logRequest, _ := c.ServiceLogs(context.Background(), id, types.ContainerLogsOptions{
				Follow:     false,
				ShowStdout: true,
				ShowStderr: true,
				Timestamps: true,
				Details:    false,
			})
			defer logRequest.Close()

			//	, ShowStderr: true, ShowStdout: true})
			res, _ := ioutil.ReadAll(logRequest)
			fmt.Println(string(res[:]))

			done = true
		} else {
			fmt.Printf(".")
		}
	}
	return done
}