worker: remove ContainerProvider

[ddadlani]

combine containerProvider and worker
add workerHelper which stores helper functions

Signed-off-by: Divya Dadlani ddadlani@pivotal.io
Co-authored-by: Krishna Mannem kmannem@pivotal.io

fixes #3052

[vito]

😮

[ddadlani]

Preliminary thoughts?

One of the things we are not happy with is the length of createVolumes

concourse/atc/worker/worker.go

Lines 324 to 465 in 9555027

	func (worker *gardenWorker) createVolumes(logger lager.Logger, isPrivileged bool, creatingContainer db.CreatingContainer, spec ContainerSpec) ([]VolumeMount, error) {
	var volumeMounts []VolumeMount
	var ioVolumeMounts []VolumeMount
	scratchVolume, err := worker.volumeClient.FindOrCreateVolumeForContainer(
	logger,
	VolumeSpec{
	Strategy: baggageclaim.EmptyStrategy{},
	Privileged: isPrivileged,
	},
	creatingContainer,
	spec.TeamID,
	"/scratch",
	)
	if err != nil {
	return nil, err
	}
	scratchMount := VolumeMount{
	Volume: scratchVolume,
	MountPath: "/scratch",
	}
	volumeMounts = append(volumeMounts, scratchMount)
	hasSpecDirInInputs := anyMountTo(spec.Dir, getDestinationPathsFromInputs(spec.Inputs))
	hasSpecDirInOutputs := anyMountTo(spec.Dir, getDestinationPathsFromOutputs(spec.Outputs))
	if spec.Dir != "" && !hasSpecDirInOutputs && !hasSpecDirInInputs {
	workdirVolume, volumeErr := worker.volumeClient.FindOrCreateVolumeForContainer(
	logger,
	VolumeSpec{
	Strategy: baggageclaim.EmptyStrategy{},
	Privileged: isPrivileged,
	},
	creatingContainer,
	spec.TeamID,
	spec.Dir,
	)
	if volumeErr != nil {
	return nil, volumeErr
	}
	volumeMounts = append(volumeMounts, VolumeMount{
	Volume: workdirVolume,
	MountPath: spec.Dir,
	})
	}
	inputDestinationPaths := make(map[string]bool)
	for _, inputSource := range spec.Inputs {
	var inputVolume Volume
	localVolume, found, err := inputSource.Source().VolumeOn(logger, worker)
	if err != nil {
	return nil, err
	}
	cleanedInputPath := filepath.Clean(inputSource.DestinationPath())
	if found {
	inputVolume, err = worker.volumeClient.FindOrCreateCOWVolumeForContainer(
	logger,
	VolumeSpec{
	Strategy: localVolume.COWStrategy(),
	Privileged: isPrivileged,
	},
	creatingContainer,
	localVolume,
	spec.TeamID,
	cleanedInputPath,
	)
	if err != nil {
	return nil, err
	}
	} else {
	inputVolume, err = worker.volumeClient.FindOrCreateVolumeForContainer(
	logger,
	VolumeSpec{
	Strategy: baggageclaim.EmptyStrategy{},
	Privileged: isPrivileged,
	},
	creatingContainer,
	spec.TeamID,
	cleanedInputPath,
	)
	if err != nil {
	return nil, err
	}
	destData := lager.Data{
	"dest-volume": inputVolume.Handle(),
	"dest-worker": inputVolume.WorkerName(),
	}
	err = inputSource.Source().StreamTo(logger.Session("stream-to", destData), inputVolume)
	if err != nil {
	return nil, err
	}
	}
	ioVolumeMounts = append(ioVolumeMounts, VolumeMount{
	Volume: inputVolume,
	MountPath: cleanedInputPath,
	})
	inputDestinationPaths[cleanedInputPath] = true
	}
	for _, outputPath := range spec.Outputs {
	cleanedOutputPath := filepath.Clean(outputPath)
	// reuse volume if output path is the same as input
	if inputDestinationPaths[cleanedOutputPath] {
	continue
	}
	outVolume, volumeErr := worker.volumeClient.FindOrCreateVolumeForContainer(
	logger,
	VolumeSpec{
	Strategy: baggageclaim.EmptyStrategy{},
	Privileged: isPrivileged,
	},
	creatingContainer,
	spec.TeamID,
	cleanedOutputPath,
	)
	if volumeErr != nil {
	return nil, volumeErr
	}
	ioVolumeMounts = append(ioVolumeMounts, VolumeMount{
	Volume: outVolume,
	MountPath: cleanedOutputPath,
	})
	}
	sort.Sort(byMountPath(ioVolumeMounts))
	volumeMounts = append(volumeMounts, ioVolumeMounts...)
	return volumeMounts, nil
	}

and are looking to cut that down.

The main advantage that this refactor gives us is the isolation of findOrInitializeContainer

concourse/atc/worker/worker.go

Line 187 in 9555027

creatingContainer, createdContainer, containerHandle, err = worker.helper.findOrInitializeContainer(logger, owner, metadata)

which allows us to lock CreatingContainer creation for #3301

The second advantage is that it attempts to decouple volume and container creation in preparation for concourse/rfcs#20

[kcmannem]

Our other streams of work are based on this branch. We wanna integrate it into master. We pulled apart as much as we could without artifacts gc (volumes not dependent on containers). Another reason is to remove a the CreatingContainerLock which is unnecessary.

[vito]

tbh not much to review here since it's primarily slingin' code around, but it passes testflight/watsjs, so let's see how it fares in prod. 💥