91 lines
2.1 KiB
Go
91 lines
2.1 KiB
Go
package main
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import (
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"fmt"
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"github.com/docker/docker/api/types"
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"github.com/docker/docker/client"
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"github.com/robfig/cron"
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"golang.org/x/net/context"
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"strings"
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"time"
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)
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var WatchInterval = (5 * time.Second)
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type ContainerStartJob struct {
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Client *client.Client
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ContainerID string
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Context context.Context
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Name string
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Schedule string
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}
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func (job ContainerStartJob) Run() {
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fmt.Println("Starting:", job.Name)
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err := job.Client.ContainerStart(job.Context, job.ContainerID, types.ContainerStartOptions{})
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if err != nil {
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panic(err)
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}
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}
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func QueryScheduledJobs(cli *client.Client) (jobs []ContainerStartJob) {
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fmt.Println("Scanning containers for new schedules...")
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containers, err := cli.ContainerList(context.Background(), types.ContainerListOptions{All: true})
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if err != nil {
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panic(err)
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}
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for _, container := range containers {
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if val, ok := container.Labels["cron.schedule"]; ok {
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jobName := strings.Join(container.Names, "/")
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jobs = append(jobs, ContainerStartJob{
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Schedule: val,
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Client: cli,
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ContainerID: container.ID,
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Context: context.Background(),
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Name: jobName,
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})
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}
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}
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return
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}
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func ScheduleJobs(c *cron.Cron, jobs []ContainerStartJob) {
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for _, job := range jobs {
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fmt.Printf("Scheduling %s (%s) with schedule '%s'\n", job.Name, job.ContainerID[:10], job.Schedule)
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c.AddJob(job.Schedule, job)
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}
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}
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func main() {
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cli, err := client.NewEnvClient()
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if err != nil {
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panic(err)
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}
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// Create a cron
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c := cron.New()
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// Start the loop
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for {
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fmt.Println("Tick...")
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// HACK: This is risky as it could fall on the same interval as a task and that task would get skipped
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// It would be best to manage a ContainerID to Job mapping and then remove entries that are missing
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// in the new list and add new entries. However, cron does not support this yet.
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// Stop and create a new cron
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c.Stop()
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c = cron.New()
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// Schedule jobs again
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jobs := QueryScheduledJobs(cli)
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ScheduleJobs(c, jobs)
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c.Start()
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// Sleep until the next query time
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time.Sleep(WatchInterval)
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}
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}
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