oc-schedulerd/daemons/execution_manager.go

package daemons

import (
	"bytes"
	"oc-scheduler/conf"
	"oc-scheduler/logger"
	"oc-scheduler/models"
	"oc-scheduler/workflow_builder"
	"os"
	"os/exec"
	"regexp"
	"text/template"
	"time"
)

type ExecutionManager struct {
	bookings	*models.ScheduledBooking
	executions	[]models.Booking	
}

type manifestValues struct{
	ARGO_FILE 		string
	LOKI_URL  		string
	CONTAINER_NAME 	string
}

func (em *ExecutionManager) SetBookings(b *models.ScheduledBooking){
	em.bookings = b
}

// Loop every second on the booking's list and move the booking that must start to a new list
// that will be looped over to start them
func (em *ExecutionManager) RetrieveNextExecutions(){


	if(em.bookings == nil){
		logger.Logger.Fatal().Msg("booking has not been set in the exection manager")
	}

	for(true){
		logger.Logger.Debug().Msg("New loop")
		em.bookings.Mu.Lock()
		bookings :=  em.bookings.Bookings
		if (len(bookings) > 0){	
			for i := len( bookings) - 1 ; i  >= 0 ; i--{
				logger.Logger.Debug().Msg("It should start at " + bookings[i].Start.String() + " and it is now " + time.Now().UTC() .String())
				if (bookings[i].Start.Before(time.Now().UTC())){
					logger.Logger.Info().Msg("Will execute " + bookings[i].Workflow + " soon")
					go em.executeBooking(bookings[i])
					bookings = append(bookings[:i], bookings[i+1:]...)
					em.bookings.Bookings = bookings
				}
			}
		}	 
		em.bookings.Mu.Unlock()
		time.Sleep(time.Second)
	}

}

func (em *ExecutionManager) executeBooking(booking models.Booking){

	// create argo
	new_graph := workflow_builder.Graph{}
	
	err := new_graph.LoadFrom(booking.Workflow)
	if err != nil {
		logger.Logger.Error().Msg("Could not retrieve workflow " + booking.Workflow + " from oc-catalog API")
	}

	argo_file_path, err := new_graph.ExportToArgo()
	if err != nil {
		logger.Logger.Error().Msg("Could not create the Argo file for " + booking.Workflow )
		logger.Logger.Error().Msg(err.Error())
	}

	logger.Logger.Debug().Msg("Created :" + argo_file_path)
	// start execution 
	// create the yaml that describes the pod : filename, path/url to Loki
	manifest, err := em.CreateManifest(booking, argo_file_path)
	if err != nil {
		logger.Logger.Error().Msg("Could not create manifest " + err.Error())
	}

	// launch a pod that contains oc-monitor, give it the name of the workflow
	cmd := exec.Command("kubectl","apply","-f", "manifests/"+manifest)
	output , err := cmd.CombinedOutput()
	if err != nil {
		logger.Logger.Error().Msg("failed to create new pod for " + booking.Workflow + " :" + err.Error())
		return 
	}
	
	logger.Logger.Debug().Msg("Result from kubectl apply : " + string(output))

	// Transfer the argo file to the pod

	cmd = exec.Command("kubectl","cp", "argo_workflows/" + argo_file_path, "pods/test-monitor:/app/workflows", "-c", "oc-monitor-" +  getContainerName(argo_file_path))
	output, err  = cmd.CombinedOutput()
	if err != nil {
		logger.Logger.Error().Msg("failed to copy argo file to " + booking.Workflow + " :" + err.Error())
		return
	}
	
	logger.Logger.Debug().Msg("Result from kubectl cp : " + string(output))

}

func (*ExecutionManager) CreateManifest(booking models.Booking, argo_file string) (manifest_filepath string, err error) {

	var filled_template bytes.Buffer

	manifest_file, err := os.ReadFile("conf/monitor_pod_template.yml")
	if err != nil {
		logger.Logger.Error().Msg("Could not open the k8s template file for " + booking.Workflow)
		return "", err
	}

	container_name := getContainerName(argo_file)
	tmpl, err := template.New("manifest_template").Parse(string(manifest_file))
	if err != nil {
		logger.Logger.Error().Msg(err.Error())
		return "", err
	}

	manifest_data := manifestValues{
		ARGO_FILE: argo_file,
		LOKI_URL: conf.GetConfig().Logs,
		CONTAINER_NAME: container_name,
	}

	err = tmpl.Execute(&filled_template, manifest_data)
	if err != nil {
		logger.Logger.Error().Msg("Could not complete manifest template for " + booking.Workflow)
		return "", err	}


	manifest_filepath = booking.Workflow + "_manifest.yaml"

	err = os.WriteFile("manifests/" + manifest_filepath, filled_template.Bytes(),0644)
	if err != nil {
		logger.Logger.Error().Msg("Could not write the YAML file for " + booking.Workflow + "'s manifest")
		return "", err
	}

	return manifest_filepath, nil
}

func getContainerName(argo_file string) string {
	regex := "([a-zA-Z]+-[a-zA-Z]+)"
	re := regexp.MustCompile(regex)

	container_name := re.FindString(argo_file)
	return container_name

}