Move Nomad job creation logic to environment manager

2021-05-25 16:18:10 +02:00
parent 619cd40fb6
commit 4c3cc0cc4c
7 changed files with 141 additions and 131 deletions
--- a/environment/job.go
+++ b/environment/job.go
@@ -0,0 +1,130 @@
+package environment
+
+import (
+	_ "embed"
+	"fmt"
+	nomadApi "github.com/hashicorp/nomad/api"
+	"github.com/hashicorp/nomad/jobspec2"
+	"gitlab.hpi.de/codeocean/codemoon/poseidon/nomad"
+	"strconv"
+)
+
+const (
+	DefaultTaskDriver = "docker"
+	TaskNameFormat    = "%s-task"
+)
+
+//go:embed default-job.hcl
+var defaultJobHCL string
+
+func parseJob(jobHCL string) *nomadApi.Job {
+	config := jobspec2.ParseConfig{
+		Body:    []byte(jobHCL),
+		AllowFS: false,
+		Strict:  true,
+	}
+	job, err := jobspec2.ParseWithConfig(&config)
+	if err != nil {
+		log.WithError(err).Fatal("Error parsing default Nomad job")
+		return nil
+	}
+
+	return job
+}
+
+func createTaskGroup(job *nomadApi.Job, name string, prewarmingPoolSize uint) *nomadApi.TaskGroup {
+	var taskGroup *nomadApi.TaskGroup
+	if len(job.TaskGroups) == 0 {
+		taskGroup = nomadApi.NewTaskGroup(name, int(prewarmingPoolSize))
+		job.TaskGroups = []*nomadApi.TaskGroup{taskGroup}
+	} else {
+		taskGroup = job.TaskGroups[0]
+		taskGroup.Name = &name
+		count := int(prewarmingPoolSize)
+		taskGroup.Count = &count
+	}
+	return taskGroup
+}
+
+func configureNetwork(taskGroup *nomadApi.TaskGroup, networkAccess bool, exposedPorts []uint16) {
+	if len(taskGroup.Tasks) == 0 {
+		// This function is only used internally and must be called after configuring the task.
+		// This error is not recoverable.
+		log.Fatal("Can't configure network before task has been configured!")
+	}
+	task := taskGroup.Tasks[0]
+
+	if networkAccess {
+		var networkResource *nomadApi.NetworkResource
+		if len(taskGroup.Networks) == 0 {
+			networkResource = &nomadApi.NetworkResource{}
+			taskGroup.Networks = []*nomadApi.NetworkResource{networkResource}
+		} else {
+			networkResource = taskGroup.Networks[0]
+		}
+		// prefer "bridge" network over "host" to have an isolated network namespace with bridged interface
+		// instead of joining the host network namespace
+		networkResource.Mode = "bridge"
+		for _, portNumber := range exposedPorts {
+			port := nomadApi.Port{
+				Label: strconv.FormatUint(uint64(portNumber), 10),
+				To:    int(portNumber),
+			}
+			networkResource.DynamicPorts = append(networkResource.DynamicPorts, port)
+		}
+	} else {
+		// somehow, we can't set the network mode to none in the NetworkResource on task group level
+		// see https://github.com/hashicorp/nomad/issues/10540
+		if task.Config == nil {
+			task.Config = make(map[string]interface{})
+		}
+		task.Config["network_mode"] = "none"
+	}
+}
+
+func configureTask(
+	taskGroup *nomadApi.TaskGroup,
+	name string,
+	cpuLimit, memoryLimit uint,
+	image string,
+	networkAccess bool,
+	exposedPorts []uint16) {
+	var task *nomadApi.Task
+	if len(taskGroup.Tasks) == 0 {
+		task = nomadApi.NewTask(name, DefaultTaskDriver)
+		taskGroup.Tasks = []*nomadApi.Task{task}
+	} else {
+		task = taskGroup.Tasks[0]
+		task.Name = name
+	}
+	iCpuLimit := int(cpuLimit)
+	iMemoryLimit := int(memoryLimit)
+	task.Resources = &nomadApi.Resources{
+		CPU:      &iCpuLimit,
+		MemoryMB: &iMemoryLimit,
+	}
+
+	if task.Config == nil {
+		task.Config = make(map[string]interface{})
+	}
+	task.Config["image"] = image
+
+	configureNetwork(taskGroup, networkAccess, exposedPorts)
+}
+
+func (m *NomadEnvironmentManager) createJob(
+	id string,
+	prewarmingPoolSize, cpuLimit, memoryLimit uint,
+	image string,
+	networkAccess bool,
+	exposedPorts []uint16) *nomadApi.Job {
+
+	job := m.defaultJob
+	job.ID = &id
+	job.Name = &id
+
+	var taskGroup = createTaskGroup(&job, fmt.Sprintf(nomad.TaskGroupNameFormat, id), prewarmingPoolSize)
+	configureTask(taskGroup, fmt.Sprintf(TaskNameFormat, id), cpuLimit, memoryLimit, image, networkAccess, exposedPorts)
+
+	return &job
+}