Add runsc OCI annotations to support CRI-O.

Obligatory https://xkcd.com/927

Fixes #626

1 files changed, 97 insertions, 0 deletions

diff --git a/runsc/specutils/cri.go b/runsc/specutils/cri.go
new file mode 100644
index 000000000..5318ec1fa
--- /dev/null
+++ b/runsc/specutils/cri.go
@@ -0,0 +1,97 @@
+package specutils
+
+import (
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+const (
+	// ContainerdContainerTypeAnnotation is the OCI annotation set by
+	// containerd to indicate whether the container to create should have
+	// its own sandbox or a container within an existing sandbox.
+	ContainerdContainerTypeAnnotation = "io.kubernetes.cri.container-type"
+	// ContainerdContainerTypeContainer is the container type value
+	// indicating the container should be created in an existing sandbox.
+	ContainerdContainerTypeContainer = "container"
+	// ContainerdContainerTypeSandbox is the container type value
+	// indicating the container should be created in a new sandbox.
+	ContainerdContainerTypeSandbox = "sandbox"
+
+	// ContainerdSandboxIDAnnotation is the OCI annotation set to indicate
+	// which sandbox the container should be created in when the container
+	// is not the first container in the sandbox.
+	ContainerdSandboxIDAnnotation = "io.kubernetes.cri.sandbox-id"
+
+
+	// CRIOContainerTypeAnnotation is the OCI annotation set by
+	// CRI-O to indicate whether the container to create should have
+	// its own sandbox or a container within an existing sandbox.
+	CRIOContainerTypeAnnotation = "io.kubernetes.cri-o.ContainerType"
+
+	// CRIOContainerTypeContainer is the container type value
+	// indicating the container should be created in an existing sandbox.
+	CRIOContainerTypeContainer = "container"
+	// CRIOContainerTypeSandbox is the container type value
+	// indicating the container should be created in a new sandbox.
+	CRIOContainerTypeSandbox = "sandbox"
+
+	// CRIOSandboxIDAnnotation is the OCI annotation set to indicate
+	// which sandbox the container should be created in when the container
+	// is not the first container in the sandbox.
+	CRIOSandboxIDAnnotation = "io.kubernetes.cri-o.SandboxID"
+)
+
+// ContainerType represents the type of container requested by the calling container manager.
+type ContainerType int
+
+const (
+	// ContainerTypeUnspecified indicates that no known container type
+	// annotation was found in the spec.
+	ContainerTypeUnspecified ContainerType = iota
+	// ContainerTypeUnknown indicates that a container type was specified
+	// but is unknown to us.
+	ContainerTypeUnknown
+	// ContainerTypeSandbox indicates that the container should be run in a
+	// new sandbox.
+	ContainerTypeSandbox
+	// ContainerTypeContainer indicates that the container should be run in
+	// an existing sandbox.
+	ContainerTypeContainer
+)
+
+// SpecContainerType tries to determine the type of container specified by the
+// container manager using well-known container annotations.
+func SpecContainerType(spec *specs.Spec) ContainerType {
+	if t, ok := spec.Annotations[ContainerdContainerTypeAnnotation]; ok {
+		switch t {
+		case ContainerdContainerTypeSandbox:
+			return ContainerTypeSandbox
+		case ContainerdContainerTypeContainer:
+			return ContainerTypeContainer
+		default:
+			return ContainerTypeUnknown
+		}
+	}
+	if t, ok := spec.Annotations[CRIOContainerTypeAnnotation]; ok {
+		switch t {
+		case CRIOContainerTypeSandbox:
+			return ContainerTypeSandbox
+		case CRIOContainerTypeContainer:
+			return ContainerTypeContainer
+		default:
+			return ContainerTypeUnknown
+		}
+	}
+	return ContainerTypeUnspecified
+}
+
+// SandboxID returns the ID of the sandbox to join and whether an ID was found
+// in the spec.
+func SandboxID(spec *specs.Spec) (string, bool) {
+	if id, ok := spec.Annotations[ContainerdSandboxIDAnnotation]; ok {
+		return id, true
+	}
+	if id, ok := spec.Annotations[CRIOSandboxIDAnnotation]; ok {
+		return id, true
+	}
+	return "", false
+}