Add the ability to turn off image pulling.

pkg/api/types.go

@@ -17,6 +17,8 @@ limitations under the License.
 package api
 
 import (
+	"strings"
+
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/fsouza/go-dockerclient"
 )
@@ -173,6 +175,38 @@ type LivenessProbe struct {
 	InitialDelaySeconds int64 `yaml:"initialDelaySeconds,omitempty" json:"initialDelaySeconds,omitempty"`
 }
 
+// PullPolicy describes a policy for if/when to pull a container image
+type PullPolicy string
+
+const (
+	// Always attempt to pull the latest image.  Container will fail If the pull fails.
+	PullAlways PullPolicy = "PullAlways"
+	// Never pull an image, only use a local image.  Container will fail if the image isn't present
+	PullNever PullPolicy = "PullNever"
+	// Pull if the image isn't present on disk. Container will fail if the image isn't present and the pull fails.
+	PullIfNotPresent PullPolicy = "PullIfNotPresent"
+)
+
+func IsPullAlways(p PullPolicy) bool {
+	// Default to pull always
+	if len(p) == 0 {
+		return true
+	}
+	return pullPoliciesEqual(p, PullAlways)
+}
+
+func IsPullNever(p PullPolicy) bool {
+	return pullPoliciesEqual(p, PullNever)
+}
+
+func IsPullIfNotPresent(p PullPolicy) bool {
+	return pullPoliciesEqual(p, PullIfNotPresent)
+}
+
+func pullPoliciesEqual(p1, p2 PullPolicy) bool {
+	return strings.ToLower(string(p1)) == strings.ToLower(string(p2))
+}
+
 // Container represents a single container that is expected to be run on the host.
 type Container struct {
 	// Required: This must be a DNS_LABEL.  Each container in a pod must
@@ -195,6 +229,8 @@ type Container struct {
 	Lifecycle     *Lifecycle     `yaml:"lifecycle,omitempty" json:"lifecycle,omitempty"`
 	// Optional: Default to false.
 	Privileged bool `json:"privileged,omitempty" yaml:"privileged,omitempty"`
+	// Optional: Policy for pulling images for this container
+	ImagePullPolicy PullPolicy `json:"imagePullPolicy" yaml:"imagePullPolicy"`
 }
 
 // Handler defines a specific action that should be taken