Golang host.FindOne函数代码示例

// GetDistro loads the task's distro and sends it to the requester.
func (as *APIServer) GetDistro(w http.ResponseWriter, r *http.Request) {
	task := MustHaveTask(r)

	// Get the distro for this task
	h, err := host.FindOne(host.ByRunningTaskId(task.Id))
	if err != nil {
		as.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	// Fall back to checking host field on task doc
	if h == nil && len(task.HostId) > 0 {
		h, err = host.FindOne(host.ById(task.HostId))
		if err != nil {
			as.LoggedError(w, r, http.StatusInternalServerError, err)
			return
		}
		h.SetRunningTask(task.Id, h.AgentRevision, h.TaskDispatchTime)
	}

	if h == nil {
		message := fmt.Errorf("No host found running task %v", task.Id)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}

	// agent can't properly unmarshal provider settings map
	h.Distro.ProviderSettings = nil
	as.WriteJSON(w, http.StatusOK, h.Distro)
}

func (as *APIServer) StartTask(w http.ResponseWriter, r *http.Request) {
	task := MustHaveTask(r)

	if !getGlobalLock(r.RemoteAddr, task.Id) {
		as.LoggedError(w, r, http.StatusInternalServerError, ErrLockTimeout)
		return
	}
	defer releaseGlobalLock(r.RemoteAddr, task.Id)

	evergreen.Logger.Logf(slogger.INFO, "Marking task started: %v", task.Id)

	taskStartInfo := &apimodels.TaskStartRequest{}
	if err := util.ReadJSONInto(r.Body, taskStartInfo); err != nil {
		http.Error(w, fmt.Sprintf("Error reading task start request for %v: %v", task.Id, err), http.StatusBadRequest)
		return
	}

	if err := task.MarkStart(); err != nil {
		message := fmt.Errorf("Error marking task '%v' started: %v", task.Id, err)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}

	h, err := host.FindOne(host.ByRunningTaskId(task.Id))
	if err != nil {
		message := fmt.Errorf("Error finding host running task %v: %v", task.Id, err)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}

	// Fall back to checking host field on task doc
	if h == nil && len(task.HostId) > 0 {
		evergreen.Logger.Logf(slogger.DEBUG, "Falling back to host field of task: %v", task.Id)
		h, err = host.FindOne(host.ById(task.HostId))
		if err != nil {
			as.LoggedError(w, r, http.StatusInternalServerError, err)
			return
		}
		h.SetRunningTask(task.Id, h.AgentRevision, h.TaskDispatchTime)
	}

	if h == nil {
		message := fmt.Errorf("No host found running task %v", task.Id)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}

	if err := h.SetTaskPid(taskStartInfo.Pid); err != nil {
		message := fmt.Errorf("Error calling set pid on task %v : %v", task.Id, err)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}
	as.WriteJSON(w, http.StatusOK, fmt.Sprintf("Task %v started on host %v", task.Id, h.Id))
}

func (uis *UIServer) hostPage(w http.ResponseWriter, r *http.Request) {
	projCtx := MustHaveProjectContext(r)

	vars := mux.Vars(r)
	id := vars["host_id"]

	h, err := host.FindOne(host.ById(id))
	if err != nil {
		uis.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	if h == nil {
		http.Error(w, "Host not found", http.StatusNotFound)
		return
	}

	events, err := event.Find(event.MostRecentHostEvents(id, 50))
	if err != nil {
		uis.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	flashes := PopFlashes(uis.CookieStore, r, w)
	uis.WriteHTML(w, http.StatusOK, struct {
		Flashes     []interface{}
		Events      []event.Event
		Host        *host.Host
		User        *user.DBUser
		ProjectData projectContext
	}{flashes, events, h, GetUser(r), projCtx},
		"base", "host.html", "base_angular.html", "menu.html")
}

func getHostData(hostId string) (*uiHost, error) {
	hostAsUI := &uiHost{}
	dbHost, err := host.FindOne(host.ById(hostId))
	if err != nil {
		return nil, err
	}
	if dbHost == nil {
		return nil, fmt.Errorf("Could not find host")
	}
	hostAsUI.Host = *dbHost
	return hostAsUI, nil
}

// GetDistro loads the task's distro and sends it to the requester.
func (as *APIServer) GetDistro(w http.ResponseWriter, r *http.Request) {
	task := MustHaveTask(r)

	// Get the distro for this task
	h, err := host.FindOne(host.ByRunningTaskId(task.Id))
	if err != nil {
		as.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	// agent can't properly unmarshal provider settings map
	h.Distro.ProviderSettings = nil
	as.WriteJSON(w, http.StatusOK, h.Distro)
}

// Get the host with the id specified in the request
func getHostFromRequest(r *http.Request) (*host.Host, error) {
	// get id and secret from the request.
	vars := mux.Vars(r)
	tag := vars["tag"]
	if len(tag) == 0 {
		return nil, fmt.Errorf("no host tag supplied")
	}
	// find the host
	host, err := host.FindOne(host.ById(tag))
	if host == nil {
		return nil, fmt.Errorf("no host with tag: %v", tag)
	}
	if err != nil {
		return nil, err
	}
	return host, nil
}

// returns info on the host specified
func (as *APIServer) hostInfo(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	instanceId := vars["instance_id"]

	host, err := host.FindOne(host.ById(instanceId))
	if err != nil {
		as.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	if host == nil {
		http.Error(w, "not found", http.StatusNotFound)
		return
	}

	as.WriteJSON(w, http.StatusOK, spawnResponse{HostInfo: *host})
}

func (as *APIServer) modifyHost(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	instanceId := vars["instance_id"]
	hostAction := r.FormValue("action")

	host, err := host.FindOne(host.ById(instanceId))
	if err != nil {
		as.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}
	if host == nil {
		http.Error(w, "not found", http.StatusNotFound)
		return
	}

	user := GetUser(r)
	if user == nil || user.Id != host.StartedBy {
		message := fmt.Sprintf("Only %v is authorized to terminate this host", host.StartedBy)
		http.Error(w, message, http.StatusUnauthorized)
		return
	}

	switch hostAction {
	case "terminate":
		if host.Status == evergreen.HostTerminated {
			message := fmt.Sprintf("Host %v is already terminated", host.Id)
			http.Error(w, message, http.StatusBadRequest)
			return
		}

		cloudHost, err := providers.GetCloudHost(host, &as.Settings)
		if err != nil {
			as.LoggedError(w, r, http.StatusInternalServerError, err)
			return
		}
		if err = cloudHost.TerminateInstance(); err != nil {
			as.LoggedError(w, r, http.StatusInternalServerError, fmt.Errorf("Failed to terminate spawn host: %v", err))
			return
		}
		as.WriteJSON(w, http.StatusOK, spawnResponse{HostInfo: *host})
	default:
		http.Error(w, fmt.Sprintf("Unrecognized action %v", hostAction), http.StatusBadRequest)
	}

}

func (uis *UIServer) modifyHost(w http.ResponseWriter, r *http.Request) {
	_ = MustHaveUser(r)

	vars := mux.Vars(r)
	id := vars["host_id"]

	host, err := host.FindOne(host.ById(id))
	if err != nil {
		uis.LoggedError(w, r, http.StatusInternalServerError, err)
		return
	}

	if host == nil {
		http.Error(w, "Host not found", http.StatusNotFound)
		return
	}

	opts := &uiParams{}
	err = util.ReadJSONInto(r.Body, opts)
	if err != nil {
		uis.LoggedError(w, r, http.StatusBadRequest, err)
		return
	}

	// determine what action needs to be taken
	switch opts.Action {
	case "updateStatus":
		currentStatus := host.Status
		newStatus := opts.Status
		if !util.SliceContains(validUpdateToStatuses, newStatus) {
			http.Error(w, fmt.Sprintf("'%v' is not a valid status", newStatus), http.StatusBadRequest)
			return
		}
		err := host.SetStatus(newStatus)
		if err != nil {
			uis.LoggedError(w, r, http.StatusInternalServerError, fmt.Errorf("Error updating host: %v", err))
			return
		}
		msg := NewSuccessFlash(fmt.Sprintf("Host status successfully updated from '%v' to '%v'", currentStatus, host.Status))
		PushFlash(uis.CookieStore, r, w, msg)
		uis.WriteJSON(w, http.StatusOK, "Successfully updated host status")
	default:
		uis.WriteJSON(w, http.StatusBadRequest, fmt.Sprintf("Unrecognized action: %v", opts.Action))
	}
}

// function to clean up a single task
func cleanUpTask(wrapper doomedTaskWrapper, projects map[string]model.Project) error {

	// find the appropriate project for the task
	project, ok := projects[wrapper.task.Project]
	if !ok {
		return fmt.Errorf("could not find project %v for task %v",
			wrapper.task.Project, wrapper.task.Id)
	}

	// get the host for the task
	host, err := host.FindOne(host.ById(wrapper.task.HostId))
	if err != nil {
		return fmt.Errorf("error finding host %v for task %v: %v",
			wrapper.task.HostId, wrapper.task.Id, err)
	}

	// if there's no relevant host, something went wrong
	if host == nil {
		evergreen.Logger.Logf(slogger.ERROR, "no entry found for host %v", wrapper.task.HostId)
		return wrapper.task.MarkUnscheduled()
	}

	// sanity check that the host is actually running the task
	if host.RunningTask != wrapper.task.Id {
		return fmt.Errorf("task %v says it is running on host %v, but the"+
			" host thinks it is running task %v", wrapper.task.Id, host.Id,
			host.RunningTask)
	}

	// take different action, depending on the type of task death
	switch wrapper.reason {
	case HeartbeatTimeout:
		err = cleanUpTimedOutHeartbeat(wrapper.task, project, host)
	default:
		return fmt.Errorf("unknown reason for cleaning up task: %v", wrapper.reason)
	}

	if err != nil {
		return fmt.Errorf("error cleaning up task %v: %v", wrapper.task.Id, err)
	}

	return nil

}

func (as *APIServer) StartTask(w http.ResponseWriter, r *http.Request) {
	if !getGlobalLock(APIServerLockTitle) {
		as.LoggedError(w, r, http.StatusInternalServerError, ErrLockTimeout)
		return
	}
	defer releaseGlobalLock(APIServerLockTitle)

	task := MustHaveTask(r)

	evergreen.Logger.Logf(slogger.INFO, "Marking task started: %v", task.Id)

	taskStartInfo := &apimodels.TaskStartRequest{}
	if err := util.ReadJSONInto(r.Body, taskStartInfo); err != nil {
		http.Error(w, fmt.Sprintf("Error reading task start request for %v: %v", task.Id, err), http.StatusBadRequest)
		return
	}

	if err := task.MarkStart(); err != nil {
		message := fmt.Errorf("Error marking task '%v' started: %v", task.Id, err)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}

	host, err := host.FindOne(host.ByRunningTaskId(task.Id))
	if err != nil {
		message := fmt.Errorf("Error finding host running task %v: %v", task.Id, err)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}

	if host == nil {
		message := fmt.Errorf("No host found running task %v: %v", task.Id, err)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}

	if err := host.SetTaskPid(taskStartInfo.Pid); err != nil {
		message := fmt.Errorf("Error calling set pid on task %v : %v", task.Id, err)
		as.LoggedError(w, r, http.StatusInternalServerError, message)
		return
	}
	as.WriteJSON(w, http.StatusOK, fmt.Sprintf("Task %v started on host %v", task.Id, host.Id))
}

func TestTaskEndEndpoint(t *testing.T) {
	setupTlsConfigs(t)
	for tlsString, tlsConfig := range tlsConfigs {
		testTask, _, err := setupAPITestData(testConfig, "random", "linux-64", NoPatch, t)
		testutil.HandleTestingErr(err, t, "Couldn't make test data: %v", err)

		Convey("With a live api server, agent, and test task over "+tlsString, t, func() {
			testServer, err := apiserver.CreateTestServer(testConfig, tlsConfig, plugin.APIPlugins, Verbose)
			testutil.HandleTestingErr(err, t, "Couldn't create apiserver: %v", err)
			testAgent, err := createAgent(testServer, testTask)
			testutil.HandleTestingErr(err, t, "failed to create agent: %v")
			testAgent.heartbeater.Interval = 10 * time.Second
			testAgent.StartBackgroundActions(&NoopSignalHandler{})

			Convey("calling end() should update task's/host's status properly "+
				"and start running the next task", func() {
				subsequentTaskId := testTask.Id + "Two"
				details := &apimodels.TaskEndDetail{Status: evergreen.TaskSucceeded}
				taskEndResp, err := testAgent.End(details)
				time.Sleep(1 * time.Second)
				So(err, ShouldBeNil)

				taskUpdate, err := model.FindTask(testTask.Id)
				So(err, ShouldBeNil)
				So(taskUpdate.Status, ShouldEqual, evergreen.TaskSucceeded)

				testHost, err := host.FindOne(host.ById(testTask.HostId))
				So(err, ShouldBeNil)
				So(testHost.RunningTask, ShouldEqual, subsequentTaskId)

				taskUpdate, err = model.FindTask(subsequentTaskId)
				So(err, ShouldBeNil)
				So(taskUpdate.Status, ShouldEqual, evergreen.TaskDispatched)

				So(taskEndResp, ShouldNotBeNil)
				So(taskEndResp.RunNext, ShouldBeTrue)
				So(taskEndResp.TaskId, ShouldEqual, subsequentTaskId)
			})
		})
	}
}

// taskFinished constructs the appropriate response for each markEnd
// request the API server receives from an agent. The two possible responses are:
// 1. Inform the agent of another task to run
// 2. Inform the agent that it should terminate immediately
// The first case is the usual expected flow. The second case however, could
// occur for a number of reasons including:
// a. The version of the agent running on the remote machine is stale
// b. The host the agent is running on has been decommissioned
// c. There is no currently queued dispatchable and activated task
// In any of these aforementioned cases, the agent in question should terminate
// immediately and cease running any tasks on its host.
func (as *APIServer) taskFinished(w http.ResponseWriter, task *model.Task, finishTime time.Time) {
	taskEndResponse := &apimodels.TaskEndResponse{}

	// a. fetch the host this task just completed on to see if it's
	// now decommissioned
	host, err := host.FindOne(host.ByRunningTaskId(task.Id))
	if err != nil {
		message := fmt.Sprintf("Error locating host for task %v - set to %v: %v", task.Id,
			task.HostId, err)
		evergreen.Logger.Logf(slogger.ERROR, message)
		taskEndResponse.Message = message
		as.WriteJSON(w, http.StatusInternalServerError, taskEndResponse)
		return
	}
	if host == nil {
		message := fmt.Sprintf("Error finding host running for task %v - set to %v", task.Id,
			task.HostId)
		evergreen.Logger.Logf(slogger.ERROR, message)
		taskEndResponse.Message = message
		as.WriteJSON(w, http.StatusInternalServerError, taskEndResponse)
		return
	}
	if host.Status == evergreen.HostDecommissioned || host.Status == evergreen.HostQuarantined {
		markHostRunningTaskFinished(host, task, "")
		message := fmt.Sprintf("Host %v - running %v - is in state '%v'. Agent will terminate",
			task.HostId, task.Id, host.Status)
		evergreen.Logger.Logf(slogger.INFO, message)
		taskEndResponse.Message = message
		as.WriteJSON(w, http.StatusOK, taskEndResponse)
		return
	}

	// b. check if the agent needs to be rebuilt
	taskRunnerInstance := taskrunner.NewTaskRunner(&as.Settings)
	agentRevision, err := taskRunnerInstance.HostGateway.GetAgentRevision()
	if err != nil {
		markHostRunningTaskFinished(host, task, "")
		evergreen.Logger.Logf(slogger.ERROR, "failed to get agent revision: %v", err)
		taskEndResponse.Message = err.Error()
		as.WriteJSON(w, http.StatusInternalServerError, taskEndResponse)
		return
	}
	if host.AgentRevision != agentRevision {
		markHostRunningTaskFinished(host, task, "")
		message := fmt.Sprintf("Remote agent needs to be rebuilt")
		evergreen.Logger.Logf(slogger.INFO, message)
		taskEndResponse.Message = message
		as.WriteJSON(w, http.StatusOK, taskEndResponse)
		return
	}

	// c. fetch the task's distro queue to dispatch the next pending task
	nextTask, err := getNextDistroTask(task, host)
	if err != nil {
		markHostRunningTaskFinished(host, task, "")
		evergreen.Logger.Logf(slogger.ERROR, err.Error())
		taskEndResponse.Message = err.Error()
		as.WriteJSON(w, http.StatusOK, taskEndResponse)
		return
	}
	if nextTask == nil {
		markHostRunningTaskFinished(host, task, "")
		taskEndResponse.Message = "No next task on queue"
	} else {
		taskEndResponse.Message = "Proceed with next task"
		taskEndResponse.RunNext = true
		taskEndResponse.TaskId = nextTask.Id
		taskEndResponse.TaskSecret = nextTask.Secret
		markHostRunningTaskFinished(host, task, nextTask.Id)
	}

	// give the agent the green light to keep churning
	as.WriteJSON(w, http.StatusOK, taskEndResponse)
}

func (uis *UIServer) taskPage(w http.ResponseWriter, r *http.Request) {
	projCtx := MustHaveProjectContext(r)

	if projCtx.Task == nil {
		http.Error(w, "Not found", http.StatusNotFound)
		return
	}

	if projCtx.Build == nil {
		uis.LoggedError(w, r, http.StatusInternalServerError, fmt.Errorf("build not found"))
		return
	}

	if projCtx.Version == nil {
		uis.LoggedError(w, r, http.StatusInternalServerError, fmt.Errorf("version not found"))
		return
	}

	if projCtx.ProjectRef == nil {
		evergreen.Logger.Logf(slogger.ERROR, "Project ref is nil")
		uis.LoggedError(w, r, http.StatusInternalServerError, fmt.Errorf("version not found"))
		return
	}

	executionStr := mux.Vars(r)["execution"]
	archived := false
	if executionStr != "" {
		// otherwise we can look in either tasks or old_tasks
		// where tasks are looked up in the old_tasks collection with key made up of
		// the original key and the execution number joined by an "_"
		// and the tasks are looked up in the tasks collection by key and execution
		// number, so that we avoid finding the wrong execution in the tasks
		// collection
		execution, err := strconv.Atoi(executionStr)
		if err != nil {
			http.Error(w, fmt.Sprintf("Bad execution number: %v", executionStr), http.StatusBadRequest)
			return
		}
		oldTaskId := fmt.Sprintf("%v_%v", projCtx.Task.Id, executionStr)
		taskFromDb, err := model.FindOneOldTask(bson.M{"_id": oldTaskId}, db.NoProjection, db.NoSort)
		if err != nil {
			uis.LoggedError(w, r, http.StatusInternalServerError, err)
			return
		}
		archived = true
		if taskFromDb == nil {
			// for backwards compatibility with tasks without an execution
			if execution == 0 {
				taskFromDb, err = model.FindOneTask(bson.M{
					"$and": []bson.M{
						bson.M{"_id": projCtx.Task.Id},
						bson.M{"$or": []bson.M{bson.M{"execution": 0}, bson.M{"execution": nil}}}}},
					db.NoProjection,
					db.NoSort)
			} else {
				taskFromDb, err = model.FindOneTask(bson.M{"_id": projCtx.Task.Id, "execution": execution},
					db.NoProjection, db.NoSort)
			}
			if err != nil {
				uis.LoggedError(w, r, http.StatusInternalServerError, fmt.Errorf("Error finding old task: %v", err))
				return
			}
		}
		projCtx.Task = taskFromDb
	}

	// Build a struct containing the subset of task data needed for display in the UI

	task := uiTaskData{
		Id:                  projCtx.Task.Id,
		DisplayName:         projCtx.Task.DisplayName,
		Revision:            projCtx.Task.Revision,
		Status:              projCtx.Task.Status,
		TaskEndDetails:      projCtx.Task.Details,
		Distro:              projCtx.Task.DistroId,
		BuildVariant:        projCtx.Task.BuildVariant,
		BuildId:             projCtx.Task.BuildId,
		Activated:           projCtx.Task.Activated,
		Restarts:            projCtx.Task.Restarts,
		Execution:           projCtx.Task.Execution,
		Requester:           projCtx.Task.Requester,
		StartTime:           projCtx.Task.StartTime.UnixNano(),
		DispatchTime:        projCtx.Task.DispatchTime.UnixNano(),
		FinishTime:          projCtx.Task.FinishTime.UnixNano(),
		ExpectedDuration:    projCtx.Task.ExpectedDuration,
		PushTime:            projCtx.Task.PushTime,
		TimeTaken:           projCtx.Task.TimeTaken,
		Priority:            projCtx.Task.Priority,
		TestResults:         projCtx.Task.TestResults,
		Aborted:             projCtx.Task.Aborted,
		CurrentTime:         time.Now().UnixNano(),
		BuildVariantDisplay: projCtx.Build.DisplayName,
		Message:             projCtx.Version.Message,
		Project:             projCtx.Version.Identifier,
		Author:              projCtx.Version.Author,
		AuthorEmail:         projCtx.Version.AuthorEmail,
		VersionId:           projCtx.Version.Id,
		RepoOwner:           projCtx.ProjectRef.Owner,
		Repo:                projCtx.ProjectRef.Repo,
		Archived:            archived,
//.........这里部分代码省略.........

//SpawnInstance creates a new droplet for the given distro.
func (digoMgr *DigitalOceanManager) SpawnInstance(d *distro.Distro, owner string, userHost bool) (*host.Host, error) {
	if d.Provider != ProviderName {
		return nil, fmt.Errorf("Can't spawn instance of %v for distro %v: provider is %v", ProviderName, d.Id, d.Provider)
	}

	digoSettings := &Settings{}
	if err := mapstructure.Decode(d.ProviderSettings, digoSettings); err != nil {
		return nil, fmt.Errorf("Error decoding params for distro %v: %v", d.Id, err)
	}

	if err := digoSettings.Validate(); err != nil {
		return nil, fmt.Errorf("Invalid DigitalOcean settings in distro %v: %v", d.Id, err)
	}

	instanceName := "droplet-" +
		fmt.Sprintf("%v", rand.New(rand.NewSource(time.Now().UnixNano())).Int())
	intentHost := &host.Host{
		Id:               instanceName,
		User:             d.User,
		Distro:           *d,
		Tag:              instanceName,
		CreationTime:     time.Now(),
		Status:           evergreen.HostUninitialized,
		TerminationTime:  util.ZeroTime,
		TaskDispatchTime: util.ZeroTime,
		Provider:         ProviderName,
		StartedBy:        owner,
	}

	dropletReq := &digo.Droplet{
		SizeId:   digoSettings.SizeId,
		ImageId:  digoSettings.ImageId,
		RegionId: digoSettings.RegionId,
		Name:     instanceName,
		SshKey:   digoSettings.SSHKeyId,
	}

	if err := intentHost.Insert(); err != nil {
		return nil, evergreen.Logger.Errorf(slogger.ERROR, "Could not insert intent "+
			"host '%v': %v", intentHost.Id, err)
	}

	evergreen.Logger.Logf(slogger.DEBUG, "Successfully inserted intent host '%v' "+
		"for distro '%v' to signal cloud instance spawn intent", instanceName,
		d.Id)

	newDroplet, err := digoMgr.account.CreateDroplet(dropletReq)
	if err != nil {
		evergreen.Logger.Logf(slogger.ERROR, "DigitalOcean create droplet API call failed"+
			" for intent host '%v': %v", intentHost.Id, err)

		// remove the intent host document
		rmErr := intentHost.Remove()
		if rmErr != nil {
			return nil, evergreen.Logger.Errorf(slogger.ERROR, "Could not remove intent host "+
				"'%v': %v", intentHost.Id, rmErr)
		}
		return nil, err
	}

	// find old intent host
	host, err := host.FindOne(host.ById(intentHost.Id))
	if host == nil {
		return nil, evergreen.Logger.Errorf(slogger.ERROR, "Can't locate "+
			"record inserted for intended host “%v”", intentHost.Id)
	}
	if err != nil {
		return nil, evergreen.Logger.Errorf(slogger.ERROR, "Failed to look up intent host %v: %v",
			intentHost.Id, err)
	}

	host.Id = fmt.Sprintf("%v", newDroplet.Id)
	host.Host = newDroplet.IpAddress
	err = host.Insert()
	if err != nil {
		return nil, evergreen.Logger.Errorf(slogger.ERROR, "Failed to insert new host %v"+
			"for intent host %v: %v", host.Id, intentHost.Id, err)
	}

	// remove the intent host document
	err = intentHost.Remove()
	if err != nil {
		return nil, evergreen.Logger.Errorf(slogger.ERROR, "Could not remove "+
			"insert host “%v” (replaced by “%v”): %v", intentHost.Id, host.Id,
			err)
	}
	return host, nil

}