github.com/AliyunContainerService/cli@v0.0.0-20181009023821-814ced4b30d0/internal/pkg/containerized/pauseandrun.go (about)

     1  package containerized
     2  
     3  import (
     4  	"context"
     5  
     6  	"github.com/containerd/containerd"
     7  	"github.com/containerd/containerd/errdefs"
     8  	"github.com/pkg/errors"
     9  	"github.com/sirupsen/logrus"
    10  )
    11  
    12  // AtomicImageUpdate will perform an update of the given container with the new image
    13  // and verify success via the provided healthcheckFn.  If the healthcheck fails, the
    14  // container will be reverted to the prior image
    15  func AtomicImageUpdate(ctx context.Context, container containerd.Container, image containerd.Image, healthcheckFn func() error) error {
    16  	updateCompleted := false
    17  	err := pauseAndRun(ctx, container, func() error {
    18  		if err := container.Update(ctx, WithUpgrade(image)); err != nil {
    19  			return errors.Wrap(err, "failed to update to new image")
    20  		}
    21  		updateCompleted = true
    22  		task, err := container.Task(ctx, nil)
    23  		if err != nil {
    24  			if errdefs.IsNotFound(err) {
    25  				return nil
    26  			}
    27  			return errors.Wrap(err, "failed to lookup task")
    28  		}
    29  		return task.Kill(ctx, sigTERM)
    30  	})
    31  	if err != nil {
    32  		if updateCompleted {
    33  			logrus.WithError(err).Error("failed to update, rolling back")
    34  			return rollBack(ctx, container)
    35  		}
    36  		return err
    37  	}
    38  	if err := healthcheckFn(); err != nil {
    39  		logrus.WithError(err).Error("failed health check, rolling back")
    40  		return rollBack(ctx, container)
    41  	}
    42  	return nil
    43  }
    44  
    45  func rollBack(ctx context.Context, container containerd.Container) error {
    46  	return pauseAndRun(ctx, container, func() error {
    47  		if err := container.Update(ctx, WithRollback); err != nil {
    48  			return err
    49  		}
    50  		task, err := container.Task(ctx, nil)
    51  		if err != nil {
    52  			if errdefs.IsNotFound(err) {
    53  				return nil
    54  			}
    55  			return errors.Wrap(err, "failed to lookup task")
    56  		}
    57  		return task.Kill(ctx, sigTERM)
    58  	})
    59  }
    60  
    61  func pauseAndRun(ctx context.Context, container containerd.Container, fn func() error) error {
    62  	task, err := container.Task(ctx, nil)
    63  	if err != nil {
    64  		if errdefs.IsNotFound(err) {
    65  			return fn()
    66  		}
    67  		return errors.Wrap(err, "failed to lookup task")
    68  	}
    69  	if err := task.Pause(ctx); err != nil {
    70  		return errors.Wrap(err, "failed to pause task")
    71  	}
    72  	defer task.Resume(ctx)
    73  	return fn()
    74  }