oc-catalog/models/workflow.go

package models

import (
	"context"
	"encoding/xml"
	"errors"
	"sort"
	"time"

	"cloud.o-forge.io/core/oc-catalog/models/rtype"
	swagger "cloud.o-forge.io/core/oc-catalog/selfapi"
	"cloud.o-forge.io/core/oc-catalog/services"
	"github.com/beego/beego/v2/core/logs"
	"github.com/vk496/cron"
	"go.mongodb.org/mongo-driver/bson/primitive"
)

type LinkingState uint

// When we check the schedule of a workflow, we report with this
type DCstatus struct {
	DCname      string
	DCobjID     string //FIXME: Probably should be model ID
	IsReachable bool

	IsAvailable bool
	Booked      *ScheduleInfo

	ErrorMessage string
}

const (
	NO_LINK LinkingState = iota
	INPUT
	OUTPUT
)

func boolToLinkingState(boolState bool) LinkingState {
	switch boolState {
	case true:
		return INPUT
	case false:
		return OUTPUT
	default:
		return NO_LINK
	}
}

const SchedulesDB = "schedules"

type Workflow struct {
	// The key of the map is the ID of the object itself
	Data       map[string]DataObject       `json:"data"`
	Computing  map[string]ComputingObject  `json:"computing"`
	Storage    map[string]StorageObject    `json:"storage"`
	Datacenter map[string]DatacenterObject `json:"datacenter"` //TODO: Decide if there should be multiple objects of a datacenter

	Schedules WorkflowSchedule `json:"schedules"`

	MxgraphXML string `description:"State of the mxgraph"`
}

type ResourceObject interface {
	getHost() *string
	getName() *string
	getModel() (ResourceModel, error)
	getRtype() rtype.Rtype
	setReference(rObjID primitive.ObjectID)
	getReference() primitive.ObjectID
	isLinked(rObjID string) LinkingState
	addLink(direction LinkingState, rObjID string)
}

// Get a sum of all execution requirements attached to a DC obj
func (w Workflow) GetExecutionRequirements(dcIDobj string) (ret ExecutionRequirementsModel, err error) {

	// Find the id of the DC obj

	if _, ok := w.Datacenter[dcIDobj]; !ok {
		return ExecutionRequirementsModel{}, errors.New("DC obj" + dcIDobj + " doesn't exist in the Workflow")
	}

	// Get all elements that are attached to the DC

	for _, computingObj := range w.Computing {
		if computingObj.DataCenterID == dcIDobj {
			mymodel, err := computingObj.getModel()
			if err != nil {
				return ExecutionRequirementsModel{}, err
			}

			compModel := mymodel.(ComputingModel)

			//TODO a generic way to concatenate execution requirements
			ret.CPUs += compModel.ExecutionRequirements.CPUs
			ret.GPUs += compModel.ExecutionRequirements.GPUs
			ret.RAM += compModel.ExecutionRequirements.RAM
		}
	}

	return
}

func (w *Workflow) GetResource(rObjID *string) (retObj ResourceObject) {

	if rObjID == nil {
		return nil
	}

	if storVal, ok := w.Data[*rObjID]; ok {
		retObj = &storVal
		return
	}

	if storVal, ok := w.Computing[*rObjID]; ok {
		retObj = &storVal
		return
	}

	if storVal, ok := w.Storage[*rObjID]; ok {
		retObj = &storVal
		return
	}

	if storVal, ok := w.Datacenter[*rObjID]; ok {
		retObj = &storVal
		return
	}

	return nil
}

func (w *Workflow) GetResourceMapByRtype(rt rtype.Rtype) interface{} {
	switch rt {
	case rtype.DATA:
		return w.Data
	case rtype.COMPUTING:
		return w.Computing
	case rtype.STORAGE:
		return w.Storage
	case rtype.DATACENTER:
		return w.Datacenter
	default:
		return nil
	}
}

func (w *Workflow) CreateResourceObject(rt rtype.Rtype) ResourceObject {
	var res ResourceObject
	switch rt {
	case rtype.DATA:
		res = &DataObject{}
	case rtype.COMPUTING:
		res = &ComputingObject{}
	case rtype.STORAGE:
		res = &StorageObject{}
	case rtype.DATACENTER:
		res = &DatacenterObject{}
	default:
		res = nil
	}
	return res
}

func (w *Workflow) AddObj(robj ResourceObject) *primitive.ObjectID {
	outputID := primitive.NewObjectID()
	w.UpdateObj(robj, outputID.Hex())

	return &outputID
}

func (w *Workflow) UpdateDB(userID, workflowName string) error {

	_, err := services.MngoCollWorkspace.UpdateOne(services.MngoCtx,
		primitive.M{"_id": userID},
		primitive.M{"$set": primitive.M{WorkflowDB + "." + workflowName: w}},
	)

	return err
}

func (w *Workflow) UpdateObj(robj ResourceObject, objID string) {
	switch robj.getRtype() {
	case rtype.DATA:
		var target DataObject
		if w.Data == nil {
			//init
			w.Data = make(map[string]DataObject)
		}
		target = *robj.(*DataObject)
		w.Data[objID] = target

	case rtype.COMPUTING:
		var target ComputingObject
		if w.Computing == nil {
			//init
			w.Computing = make(map[string]ComputingObject)
		}
		target = *robj.(*ComputingObject)
		w.Computing[objID] = target

	case rtype.STORAGE:
		var target StorageObject
		if w.Storage == nil {
			//init
			w.Storage = make(map[string]StorageObject)
		}
		target = *robj.(*StorageObject)
		w.Storage[objID] = target
	case rtype.DATACENTER:
		var target DatacenterObject
		if w.Datacenter == nil {
			//init
			w.Datacenter = make(map[string]DatacenterObject)
		}
		target = *robj.(*DatacenterObject)
		w.Datacenter[objID] = target
	}

}

func GetWorkflow(userID, workflowName string) (workflow *Workflow, err error) {

	userWorkspace := GetWorkspace(userID)

	if userWorkspace != nil {
		if theWorkflow, ok := userWorkspace.Workflows[workflowName]; ok {
			return &theWorkflow, nil
		}
		logs.Debug("No workflow name")
		return nil, errors.New("No workflow name")
	}

	logs.Debug("No workspace")
	return nil, errors.New("No workspace")
}

func CreateWorkflow(userID, workflowName string) (err error) {

	//TODO: Maybe operate directly in the DB instead retriving the full object?
	userWorkspace := GetWorkspace(userID)

	// Exist in the DB
	if userWorkspace != nil {

		if _, ok := userWorkspace.Workflows[workflowName]; ok {
			message := "Workspace workflow " + workflowName +
				" is already created for user " + userID
			logs.Debug(message)
			return errors.New(message)
		}

		userWP := &Workflow{}

		// New element
		addElem := primitive.M{WorkflowDB + "." + workflowName: userWP}

		// If user doesn't have workflows, we must init at least one
		if userWorkspace.Workflows == nil {
			addElem = primitive.M{WorkflowDB: map[string]*Workflow{
				workflowName: userWP,
			}}
		}

		_, err := services.MngoCollWorkspace.UpdateOne(services.MngoCtx,
			primitive.M{"_id": userID},
			primitive.M{"$set": addElem},
		)

		if err != nil {
			message := "Internal error when updating in DB"
			logs.Debug(message + "; " + err.Error())
			return errors.New(message)
		}
		return nil
	}

	return errors.New("Can't create a workflow without a workspace")
}

func CreateObjectInWorkflow(userID, workflowName, rID string) (rObjID2 *string, err error) {

	userWorkspace := GetWorkspace(userID)

	if userWorkspace == nil {
		return nil, errors.New("No workspace for user " + userID)
	}

	if _, ok := userWorkspace.Workflows[workflowName]; !ok {
		return nil, errors.New("Workspace workflow " + workflowName + " doesn't exist for user " + userID)
	}

	rIDObj, err := primitive.ObjectIDFromHex(rID)

	if err != nil {
		return nil, errors.New("ID " + rID + " is not valid")
	}

	//TODO: We are replacing the entire array instead of pushing
	// a new element. Probably will have problems with multithread/async
	// operations and consistency in the future

	for rtyp, resource := range userWorkspace.GetResources() {
		if contains(resource, rID) {
			wWorkflow := userWorkspace.Workflows[workflowName]

			newObj := wWorkflow.CreateResourceObject(rtyp)
			newObj.setReference(rIDObj)

			outputID := wWorkflow.AddObj(newObj)

			_, err := services.MngoCollWorkspace.UpdateOne(services.MngoCtx,
				primitive.M{"_id": userID},
				primitive.M{"$set": primitive.M{WorkflowDB + "." + workflowName + "." + rtyp.String(): wWorkflow.GetResourceMapByRtype(rtyp)}},
			)

			if err != nil {
				return nil, errors.New("Internal error when updating in DB: " + err.Error())
			}

			outStr := outputID.Hex()

			return &outStr, nil
		}
	}

	return nil, errors.New("rID " + rID + " doesn't exist in the user workspace")
}

func LinkObjectsInWorkspace(userID, workflowName, rObjIDsource string, isInput bool, rObjIDtarger string) (err error) {
	userWorkspace := GetWorkspace(userID)

	if userWorkspace == nil {
		return errors.New("No workspace for user " + userID)
	}

	if _, ok := userWorkspace.Workflows[workflowName]; !ok {
		return errors.New("Workspace workflow " + workflowName + " doesn't exist for user " + userID)
	}

	// Check rObjIDsource
	if _, ok := userWorkspace.Workflows[workflowName].Data[rObjIDsource]; !ok {
		return errors.New("rObjIDsource must be of type DATA for now")
	}

	// Check rObjIDtarger

	wWorkflow := userWorkspace.Workflows[workflowName]

	resObjTarget := wWorkflow.GetResource(&rObjIDtarger)

	if resObjTarget == nil {
		return errors.New("rObjIDtarger doesn't exist")
	} else if resObjTarget.getRtype() == rtype.DATA {
		return errors.New("rObjIDtarger of type Data doesn't have inputs/outputs")
	}

	if resObjTarget.isLinked(rObjIDsource) != NO_LINK {
		return errors.New("rObjIDsource already exists in the inputs or outputs")
	}

	resObjTarget.addLink(boolToLinkingState(isInput), rObjIDsource)

	_, err = services.MngoCollWorkspace.UpdateOne(services.MngoCtx,
		primitive.M{"_id": userID},
		primitive.M{"$set": primitive.M{
			WorkflowDB + "." +
				workflowName + "." +
				resObjTarget.getRtype().String() + "." +
				rObjIDtarger: resObjTarget}},
	)

	if err != nil {
		return errors.New("Internal error when updating in DB: " + err.Error())
	}

	return nil
}

func GetWorkflowSchedule(username, workflowName string) (Currentschedule *WorkflowSchedule, err error) {

	userWorkspace := GetWorkspace(username)

	if userWorkspace == nil {
		return nil, errors.New("No workspace for user " + username)
	}

	if workflow, ok := userWorkspace.Workflows[workflowName]; ok {
		Currentschedule = &workflow.Schedules
	}

	return
}

func SetWorkflowSchedule(username, workflowName, cronString, events string, isService bool, startDate, stopDate time.Time, duration uint) (NextSchedules *ScheduleInfo, err error) {

	userWorkspace := GetWorkspace(username)

	if userWorkspace == nil {
		return nil, errors.New("No workspace for user " + username)
	}

	// Check if workflow exist
	if _, ok := userWorkspace.Workflows[workflowName]; !ok {
		return
	}

	// We mustn't modify a booked schedule
	if userWorkspace.Workflows[workflowName].Schedules.IsBooked {
		return nil, errors.New("A booked schedule can't be modified")
	}

	sch := WorkflowSchedule{}
	NextSchedules = &ScheduleInfo{}

	sch.StartDate = startDate
	sch.StopDate = stopDate
	sch.IsService = isService

	if isService { // Service
		NextSchedules.NextExecutions[0] = startDate.String()
		NextSchedules.Total = 1
	}

	if !isService { // Task
		sch.Cron = cronString
		sch.Duration = duration
		sch.Events = events

		// Obtain next executions
		counter := 0
		myCron, _ := cron.Parse(cronString)      // NOTE: already checked in the controller
		scheduledStart := myCron.Next(startDate) // Get the first execution starting from startDate

		for !scheduledStart.IsZero() && counter < MAX_SCHEDULES {
			scheduleStop := scheduledStart.Add(time.Second * time.Duration(duration))
			if scheduleStop.After(stopDate) || scheduledStart.Before(startDate) {
				// If a task is longer than last possible date, we ignore it
				scheduledStart = myCron.Next(scheduledStart)
				counter++
				continue
			}

			if counter < len(NextSchedules.NextExecutions) {
				NextSchedules.NextExecutions[counter] = scheduledStart.String()
			}

			scheduledStart = myCron.Next(scheduledStart)
			counter++
		}

		NextSchedules.Total = counter

		if NextSchedules.Total == 0 {
			return nil, errors.New("Current Task configuration will have 0 executions")
		}
	}

	_, err = services.MngoCollWorkspace.UpdateOne(services.MngoCtx,
		primitive.M{"_id": username},
		primitive.M{"$set": primitive.M{
			WorkflowDB + "." +
				workflowName + "." +
				SchedulesDB: &sch}},
	)

	if err != nil {
		return nil, errors.New("Internal error when updating in DB: " + err.Error())
	}

	return
}

func GetMxGraph(username, workflowName string) (xmlData *string, err error) {
	userWorkspace := GetWorkspace(username)

	if userWorkspace == nil {
		return nil, errors.New("No workspace for user " + username)
	}

	if _, ok := userWorkspace.Workflows[workflowName]; !ok {
		return nil, errors.New("Workspace workflow " + workflowName + " doesn't exist for user " + username)
	}

	var data string = userWorkspace.Workflows[workflowName].MxgraphXML

	if data == "" {
		xmlData = nil
	} else {
		xmlData = &data
	}
	return
}

func ParseMxGraph(username, workflowName, xmlData string) (err error, mxissues []error) {

	userWorkspace := GetWorkspace(username)

	if userWorkspace == nil {
		return errors.New("No workspace for user " + username), nil
	}

	currentWorkflow, ok := userWorkspace.Workflows[workflowName]
	if !ok {
		return errors.New("No workflow " + workflowName), nil
	}

	if currentWorkflow.Schedules.IsBooked {
		return errors.New("Can't modify a booked workflow"), nil
	}

	var xmlModel MxGraphModel

	// logs.Debug(xmlData)
	err = xml.Unmarshal([]byte(xmlData), &xmlModel)
	if err != nil {
		return err, nil
	}

	targetWorkspaceWorkflow, err, mxissues := userWorkspace.ConsumeMxGraphModel(xmlModel)
	if err != nil {
		return err, nil
	}

	targetWorkspaceWorkflow.MxgraphXML = xmlData
	targetWorkspaceWorkflow.Schedules = currentWorkflow.Schedules //TODO: Probably we should move schudles outside the workflow

	_, err = services.MngoCollWorkspace.UpdateOne(services.MngoCtx,
		primitive.M{"_id": username},
		primitive.M{"$set": primitive.M{
			WorkflowDB + "." +
				workflowName: targetWorkspaceWorkflow}},
	)

	if err != nil {
		return errors.New("Internal error when updating in DB: " + err.Error()), nil
	}

	return nil, mxissues
}

// FindInSlice takes a slice and looks for an element in it. If found it will
// return it's key, otherwise it will return -1 and a bool of false.
func FindInSlice(slice []string, val string) (int, bool) {
	for i, item := range slice {
		if item == val {
			return i, true
		}
	}
	return -1, false
}

// At least one element exist in both slices
// Return index1, index2 and if exist
func FindSliceInSlice(slice1 []string, slice2 []string) (int, int, bool) {
	for i1, item1 := range slice1 {
		for i2, item2 := range slice2 {
			if item1 == item2 {
				return i1, i2, true
			}
		}
	}
	return -1, -1, false
}

func (w Workspace) ConsumeMxGraphModel(xmlmodel MxGraphModel) (ret *Workflow, err error, issues []error) {

	ret = &Workflow{}

	// When we will iterate over the full array of cells, we first will register the resources
	// and after the linkage between them
	sort.Slice(xmlmodel.Root.MxCell, func(i, j int) bool {
		return xmlmodel.Root.MxCell[i].RID != nil
	})

	for _, cell := range xmlmodel.Root.MxCell {

		switch {
		case cell.RID != nil:
			// Case of a Resource
			rType := w.getRtype(*cell.RID)

			if rType == rtype.INVALID {
				return nil,
					errors.New("Refering to a rID that is not in the workflow"),
					nil
			}

			// Generate ObjectID for the reference ID
			rIDObj, err := primitive.ObjectIDFromHex(*cell.RID)
			if err != nil {
				return nil,
					errors.New("Bad ID format: " + *cell.RID),
					nil
			}

			resObj := ret.CreateResourceObject(rType)
			resObj.setReference(rIDObj)

			ret.UpdateObj(resObj, cell.ID)
		case cell.ID == "0" || cell.ID == "1":
			// ID 0 and 1 are special cases of mxeditor
			continue
			// issues = append(issues, errors.New("MxCell with ID "+cell.ID+" doesn't have a valid link"))

		default:
			// Not root nor resource. Should be only links
			sourceObj := ret.GetResource(cell.Source)
			targetObj := ret.GetResource(cell.Target)

			if sourceObj == nil || targetObj == nil {
				if sourceObj == nil && targetObj == nil {
					issues = append(issues, errors.New("Arrow "+cell.ID+" is alone"))
				} else if sourceObj == nil {
					issues = append(issues, errors.New("Arrow ("+cell.ID+") to "+*targetObj.getName()+" without parent"))
				} else {
					issues = append(issues, errors.New("Arrow "+cell.ID+" from "+*sourceObj.getName()+" without target"))
				}

				// If is a invalid link, we can't save it in the DB
				continue
			}

			if sourceObj.getRtype() == rtype.DATACENTER || targetObj.getRtype() == rtype.DATACENTER {
				var datacenter, datacenterLinked *string

				if sourceObj.getRtype() == rtype.DATACENTER {
					datacenter = cell.Source
					datacenterLinked = cell.Target
				} else {
					datacenter = cell.Target
					datacenterLinked = cell.Source
				}

				switch ret.GetResource(datacenterLinked).getRtype() {
				case rtype.COMPUTING:
					computingObj := ret.GetResource(datacenterLinked).(*ComputingObject)

					// We should always get a ID because we already registered resources and discarded which doesn't correspond to existent models
					computingObj.DataCenterID = *datacenter
					ret.UpdateObj(computingObj, *datacenterLinked)
				}

			} else {
				targetObj.addLink(INPUT, *cell.Source)
				ret.UpdateObj(targetObj, *cell.Target) // save back

				// If we have a relationship of:
				//     Source ----> Target
				//
				// The Source will be in the INPUTs of the Target.
				// But we also must make sure that the Target will be in the OUTPUTs of the Source

				sourceObj.addLink(OUTPUT, *cell.Target)
				ret.UpdateObj(sourceObj, *cell.Source)
			}

		}
	}

	dcslist := make(map[string]bool)
	dataslist := make(map[string]bool)
	// datalist := make(map[string]bool)

	for _, comp := range ret.Computing {
		if comp.DataCenterID == "" {
			issues = append(issues, errors.New("Computing "+*comp.getName()+" without a Datacenter"))
		} else {
			// If doesn't exist in the list, means is new element to register as used
			dcslist[comp.DataCenterID] = true

		}

		for _, dcin := range comp.Inputs {
			switch ret.GetResource(&dcin).getRtype() {
			case rtype.DATA:
				dataslist[dcin] = true
			}
		}

		for _, dcout := range comp.Outputs {
			switch ret.GetResource(&dcout).getRtype() {
			case rtype.DATA:
				dataslist[dcout] = true
			}
		}

	}

	for _, va := range ret.Storage {
		if va.Inputs == nil && va.Outputs == nil {
			issues = append(issues, errors.New("Storage "+*va.getName()+" without compatible inputs and outputs"))
		}
	}

	for dcID, va := range ret.Datacenter {
		// if rID doesn't exist in the list, it means that it's not used
		if _, ok := dcslist[dcID]; !ok {
			issues = append(issues, errors.New("DC "+*va.getName()+" not atached to any Computing"))
		}
	}

	for dcID, va := range ret.Data {
		// if rID doesn't exist in the list, it means that it's not used
		if _, ok := dataslist[dcID]; !ok {
			issues = append(issues, errors.New("Data "+*va.getName()+" not atached to any Computing"))
		}
	}

	//////////////////////////////////////////////////////////
	//														//
	//  Starting from here, we check the type of resources  //
	//														//
	//////////////////////////////////////////////////////////

	// FIXME: Avoid checking twice the same cases (cycles). Ex:
	//
	// Comp1 ----> Comp2
	//
	// In this case, we will check Comp1 outputs with Comp2
	// inputs AND Comp2 inputs with Comp1 outputs, since we are
	// iterating over all existent Computing models in the Graph

	for _, comp := range ret.Computing {

		compModel, err2 := comp.getModel()
		if err = err2; err != nil {
			return
		}

		currentCompModel := compModel.(ComputingModel)

		// Come computings may not allow inputs or outputs
		if len(currentCompModel.Dinputs) == 0 && len(comp.Inputs) > 0 {
			issues = append(issues, errors.New("Computing "+compModel.getName()+" must not have any input"))
			continue
		}

		if len(currentCompModel.Doutputs) == 0 && len(comp.Outputs) > 0 {
			issues = append(issues, errors.New("Computing "+compModel.getName()+" must not have any output"))
			continue
		}

		//TODO: We should allow heterogenous inputs?
		for _, objIn := range comp.Inputs {
			resIn := ret.GetResource(&objIn)
			resInType := resIn.getRtype()
			switch resInType {
			case rtype.DATA:

				dataModel, err2 := resIn.getModel()
				if err = err2; err != nil {
					return
				}
				myDataModel := dataModel.(DataModel)

				if _, ok := FindInSlice(currentCompModel.Dinputs, myDataModel.Dtype); !ok {
					issues = append(issues, errors.New("Computing "+compModel.getName()+" can't handle inputs of type "+myDataModel.Dtype+" from Data "+dataModel.getName()))
				}

			case rtype.COMPUTING:
				inCompModel, err2 := resIn.getModel()
				if err = err2; err != nil {
					return
				}

				myInComputingModel := inCompModel.(ComputingModel)

				if _, _, ok := FindSliceInSlice(myInComputingModel.Doutputs, currentCompModel.Dinputs); !ok {
					issues = append(issues, errors.New("Computing "+compModel.getName()+" can't handle any input from "+inCompModel.getName()))
				}
			case rtype.STORAGE:
				// Storage can give use anything, so we always accept it's input for now
				continue

			default:
				issues = append(issues, errors.New("Computing "+currentCompModel.getName()+" can't have any resource of type "+resInType.String()+" (behaviour not defined)"))
			}
		}

		//TODO: We should allow heterogenous outputs?
		for _, objOut := range comp.Outputs {
			resOut := ret.GetResource(&objOut)
			resOutType := resOut.getRtype()
			switch resOutType {
			case rtype.COMPUTING:
				outCompModel, err2 := resOut.getModel()
				if err = err2; err != nil {
					return
				}

				myOutComputingModel := outCompModel.(ComputingModel)

				if _, _, ok := FindSliceInSlice(currentCompModel.Doutputs, myOutComputingModel.Dinputs); !ok {
					issues = append(issues, errors.New("Computing "+compModel.getName()+" doesn't have output data compatible with "+outCompModel.getName()))
				}
			case rtype.STORAGE:
				// Storage can save anything, so we always accept store it for now
				continue

			default:
				issues = append(issues, errors.New("Computing "+currentCompModel.getName()+" can't have any resource of type "+resOutType.String()+" (behaviour not defined)"))
			}
		}

	}

	return
}

func sumExecutionReqs(exeqReq ...ExecutionRequirementsModel) (ret ExecutionRequirementsModel) {
	for _, v := range exeqReq {
		ret.CPUs += v.CPUs
		ret.GPUs += v.GPUs
		ret.RAM += v.RAM
	}

	return
}

func CheckAndBookWorkflowSchedule(username, workflowName string, book bool) (myRet []DCstatus, err error) {

	userWorkspace := GetWorkspace(username)

	if userWorkspace == nil {
		return nil, errors.New("No workspace for user " + username)
	}

	currentWorkflow, ok := userWorkspace.Workflows[workflowName]
	if !ok {
		return nil, errors.New("No workflow " + workflowName + " for user " + username)
	}

	if currentWorkflow.Schedules.IsBooked {
		return nil, errors.New("Can't operate DCs for a already booked schedule")
	}

	// dd := &currentWorkflow

	// We can have multiple DCobjs pointing to the same DCmodel. We must sum all req of the same DCmodel
	totalDCs := make(map[primitive.ObjectID]ExecutionRequirementsModel)

	for dcIDobj, dcObj := range currentWorkflow.Datacenter {
		modelID := dcObj.getReference()

		var totalsModel ExecutionRequirementsModel
		totalsModel, err = currentWorkflow.GetExecutionRequirements(dcIDobj)
		if err != nil {
			return
		}

		if _, ok := totalDCs[modelID]; ok {
			totalDCs[modelID] = sumExecutionReqs(totalDCs[modelID], totalsModel)
		} else {
			totalDCs[modelID] = totalsModel
		}
	}

	myRet = make([]DCstatus, len(totalDCs))
	var i int
	i = -1
	for modelID, execReq := range totalDCs {
		i++
		var dcModel *DatacenterModel
		dcModel, err = GetOneDatacenter(modelID.Hex())

		if err != nil {
			return
		}

		myRet[i].DCname = dcModel.Name
		myRet[i].DCobjID = modelID.Hex()

		// retrieve the host of the DC
		host := GetHost(dcModel.Hosts)
		if host == nil {
			myRet[i].ErrorMessage = "Datacenter " + myRet[i].DCname + " doesn't have a host property"
			continue
		}

		cli := services.GetSelfAPI(*host)
		data, err := cli.ScheduleApi.ScheduleControllerCheckIfScheduleCanBeCreatedInThisDC(context.Background(),
			currentWorkflow.Schedules.Cron,
			int32(currentWorkflow.Schedules.Duration),
			currentWorkflow.Schedules.StartDate.Format(time.RFC3339),
			currentWorkflow.Schedules.StopDate.Format(time.RFC3339),
			swagger.ModelsExecutionRequirementsModel{
				Cpus: int32(execReq.CPUs),
				Gpus: int32(execReq.GPUs),
				Ram:  int32(execReq.RAM),
			},
		)

		if err != nil {
			myRet[i].ErrorMessage = err.Error()
			swErr, ok := err.(swagger.GenericSwaggerError)
			if ok {
				myRet[i].IsReachable = true
				myRet[i].ErrorMessage += ": " + string(swErr.Body())
			}
			continue
		}

		myRet[i].IsReachable = true

		if data.StatusCode == 200 {
			myRet[i].IsAvailable = true
		}

	}

	// If we only check, we should exit here
	if !book {
		return
	}

	for _, v := range myRet {
		if !v.IsAvailable {
			return
		}
	}

	i = -1
	allBooked := true
	for modelID, execReq := range totalDCs {
		i++
		// _ = v
		var dcModel *DatacenterModel
		dcModel, err = GetOneDatacenter(modelID.Hex())

		if err != nil {
			myRet[i].ErrorMessage = err.Error()
			continue
		}

		cli := services.GetSelfAPI(*GetHost(dcModel.Hosts)) // If we are here, we already check that host exists and is reachable
		data, resp, err := cli.ScheduleApi.ScheduleControllerCreateSchedule(context.Background(),
			services.DC_NAME,
			workflowName,
			currentWorkflow.Schedules.Cron,
			int32(currentWorkflow.Schedules.Duration),
			currentWorkflow.Schedules.StartDate.Format(time.RFC3339),
			currentWorkflow.Schedules.StopDate.Format(time.RFC3339),
			swagger.ModelsExecutionRequirementsModel{
				Cpus: int32(execReq.CPUs),
				Gpus: int32(execReq.GPUs),
				Ram:  int32(execReq.RAM),
			},
		)

		if err != nil {
			allBooked = false
			myRet[i].ErrorMessage = err.Error()
			swErr, ok := err.(swagger.GenericSwaggerError)
			if ok {
				myRet[i].IsReachable = true
				myRet[i].ErrorMessage += ": " + string(swErr.Body())
			}
			continue
		}

		if resp.StatusCode == 200 {
			//FIXME: Maybe some better way of casting?

			var nextExec [5]string
			for counter := 0; counter < 5; counter++ {
				nextExec[counter] = data.NextExecutions[counter]
			}

			myRet[i].Booked = &ScheduleInfo{
				Total:          int(data.Total),
				NextExecutions: nextExec,
			}
		}

	}

	// If some DC fail, we must not mark the workflow as booked
	if !allBooked {
		return
	}

	currentWorkflow.Schedules.IsBooked = true
	_, err = services.MngoCollWorkspace.UpdateOne(services.MngoCtx,
		primitive.M{"_id": username},
		primitive.M{"$set": primitive.M{
			WorkflowDB + "." +
				workflowName + "." +
				SchedulesDB: &currentWorkflow.Schedules}},
	)

	if err != nil {
		logs.Critical("Internal error when updating in DB: " + err.Error())
	}

	return myRet, nil
}