implement init containers in podman

this is the first pass at implementing init containers for podman pods.
init containersare made popular by k8s as a way to run setup for pods
before the pods standard containers run.

unlike k8s, we support two styles of init containers: always and
oneshot.  always means the container stays in the pod and starts
whenever a pod is started.  this does not apply to pods restarting.
oneshot means the container runs onetime when the pod starts and then is
removed.

Signed-off-by: Brent Baude <bbaude@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/libpod/options.go b/libpod/options.go
index 17a36008d..553206a8a 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -1768,6 +1768,21 @@ func WithPidFile(pidFile string) CtrCreateOption {
 	}
 }
 
+// WithInitCtrType indicates the container is a initcontainer
+func WithInitCtrType(containerType string) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return define.ErrCtrFinalized
+		}
+		// Make sure the type is valid
+		if containerType == define.OneShotInitContainer || containerType == define.AlwaysInitContainer {
+			ctr.config.InitContainerType = containerType
+			return nil
+		}
+		return errors.Errorf("%s is invalid init container type", containerType)
+	}
+}
+
 // Pod Creation Options
 
 // WithInfraImage sets the infra image for libpod.