podman {pod,} rm/stop: add --ignore flag

Add an --ignore flag to podman rm and stop. When specified, Podman will
ignore "no such {container,pod}" errors that occur when a specified
container/pod is not present in the store (anymore).  The motivation
behind adding this flag is to write more robust systemd services using
Podman.  A user might have manually decided to remove a container/pod
which would lead to a failure during the `ExecStop` directive of a
systemd service referencing that container/pod.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

3 files changed, 36 insertions, 13 deletions

diff --git a/pkg/adapter/containers.go b/pkg/adapter/containers.go
index 02da9ec8c..bc9554193 100644
--- a/pkg/adapter/containers.go
+++ b/pkg/adapter/containers.go
@@ -90,7 +90,7 @@ func (r *LocalRuntime) StopContainers(ctx context.Context, cli *cliconfig.StopVa
 	}
 
 	ctrs, err := shortcuts.GetContainersByContext(cli.All, cli.Latest, names, r.Runtime)
-	if err != nil {
+	if err != nil && !(cli.Ignore && errors.Cause(err) == define.ErrNoSuchCtr) {
 		return nil, nil, err
 	}
 
@@ -224,7 +224,7 @@ func (r *LocalRuntime) RemoveContainers(ctx context.Context, cli *cliconfig.RmVa
 	}
 
 	ctrs, err := shortcuts.GetContainersByContext(cli.All, cli.Latest, names, r.Runtime)
-	if err != nil {
+	if err != nil && !(cli.Ignore && errors.Cause(err) == define.ErrNoSuchCtr) {
 		// Failed to get containers. If force is specified, get the containers ID
 		// and evict them
 		if !cli.Force {
@@ -235,6 +235,10 @@ func (r *LocalRuntime) RemoveContainers(ctx context.Context, cli *cliconfig.RmVa
 			logrus.Debugf("Evicting container %q", ctr)
 			id, err := r.EvictContainer(ctx, ctr, cli.Volumes)
 			if err != nil {
+				if cli.Ignore && errors.Cause(err) == define.ErrNoSuchCtr {
+					logrus.Debugf("Ignoring error (--allow-missing): %v", err)
+					continue
+				}
 				failures[ctr] = errors.Wrapf(err, "Failed to evict container: %q", id)
 				continue
 			}
@@ -252,6 +256,10 @@ func (r *LocalRuntime) RemoveContainers(ctx context.Context, cli *cliconfig.RmVa
 			Fn: func() error {
 				err := r.RemoveContainer(ctx, c, cli.Force, cli.Volumes)
 				if err != nil {
+					if cli.Ignore && errors.Cause(err) == define.ErrNoSuchCtr {
+						logrus.Debugf("Ignoring error (--allow-missing): %v", err)
+						return nil
+					}
 					logrus.Debugf("Failed to remove container %s: %s", c.ID(), err.Error())
 				}
 				return err
diff --git a/pkg/adapter/pods.go b/pkg/adapter/pods.go
index d73a8b21b..e9f3d41a9 100644
--- a/pkg/adapter/pods.go
+++ b/pkg/adapter/pods.go
@@ -15,6 +15,7 @@ import (
 	"github.com/containers/libpod/cmd/podman/cliconfig"
 	"github.com/containers/libpod/cmd/podman/shared"
 	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/libpod/define"
 	"github.com/containers/libpod/libpod/image"
 	"github.com/containers/libpod/pkg/adapter/shortcuts"
 	ann "github.com/containers/libpod/pkg/annotations"
@@ -94,7 +95,7 @@ func (r *LocalRuntime) RemovePods(ctx context.Context, cli *cliconfig.PodRmValue
 		podids []string
 	)
 	pods, err := shortcuts.GetPodsByContext(cli.All, cli.Latest, cli.InputArgs, r.Runtime)
-	if err != nil {
+	if err != nil && !(cli.Ignore && errors.Cause(err) == define.ErrNoSuchPod) {
 		errs = append(errs, err)
 		return nil, errs
 	}
@@ -151,7 +152,7 @@ func (r *LocalRuntime) StopPods(ctx context.Context, cli *cliconfig.PodStopValue
 		podids []string
 	)
 	pods, err := shortcuts.GetPodsByContext(cli.All, cli.Latest, cli.InputArgs, r.Runtime)
-	if err != nil {
+	if err != nil && !(cli.Ignore && errors.Cause(err) == define.ErrNoSuchPod) {
 		errs = append(errs, err)
 		return nil, errs
 	}
diff --git a/pkg/adapter/shortcuts/shortcuts.go b/pkg/adapter/shortcuts/shortcuts.go
index 3e4eff555..4f6cfd6a3 100644
--- a/pkg/adapter/shortcuts/shortcuts.go
+++ b/pkg/adapter/shortcuts/shortcuts.go
@@ -2,9 +2,11 @@ package shortcuts
 
 import (
 	"github.com/containers/libpod/libpod"
+	"github.com/sirupsen/logrus"
 )
 
-// GetPodsByContext gets pods whether all, latest, or a slice of names/ids
+// GetPodsByContext returns a slice of pods. Note that all, latest and pods are
+// mutually exclusive arguments.
 func GetPodsByContext(all, latest bool, pods []string, runtime *libpod.Runtime) ([]*libpod.Pod, error) {
 	var outpods []*libpod.Pod
 	if all {
@@ -18,17 +20,24 @@ func GetPodsByContext(all, latest bool, pods []string, runtime *libpod.Runtime)
 		outpods = append(outpods, p)
 		return outpods, nil
 	}
+	var err error
 	for _, p := range pods {
-		pod, err := runtime.LookupPod(p)
-		if err != nil {
-			return nil, err
+		pod, e := runtime.LookupPod(p)
+		if e != nil {
+			// Log all errors here, so callers don't need to.
+			logrus.Debugf("Error looking up pod %q: %v", p, e)
+			if err == nil {
+				err = e
+			}
+		} else {
+			outpods = append(outpods, pod)
 		}
-		outpods = append(outpods, pod)
 	}
-	return outpods, nil
+	return outpods, err
 }
 
 // GetContainersByContext gets pods whether all, latest, or a slice of names/ids
+// is specified.
 func GetContainersByContext(all, latest bool, names []string, runtime *libpod.Runtime) (ctrs []*libpod.Container, err error) {
 	var ctr *libpod.Container
 	ctrs = []*libpod.Container{}
@@ -41,10 +50,15 @@ func GetContainersByContext(all, latest bool, names []string, runtime *libpod.Ru
 	} else {
 		for _, n := range names {
 			ctr, e := runtime.LookupContainer(n)
-			if e != nil && err == nil {
-				err = e
+			if e != nil {
+				// Log all errors here, so callers don't need to.
+				logrus.Debugf("Error looking up container %q: %v", n, e)
+				if err == nil {
+					err = e
+				}
+			} else {
+				ctrs = append(ctrs, ctr)
 			}
-			ctrs = append(ctrs, ctr)
 		}
 	}
 	return