pub const IMAGE_SPEC: &'static str = r#"IMAGE SPEC
NOTE that a default registry of `registry.hub.docker.com` is used.
Valid images can be defined using the grammar
reference := name [ ":" tag ] [ "@" digest ]
name := [domain '/'] path-component ['/' path-component]*
domain := domain-component ['.' domain-component]* [':' port-number]
domain-component := /([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])/
port-number := /[0-9]+/
path-component := alpha-numeric [separator alpha-numeric]*
alpha-numeric := /[a-z0-9]+/
separator := /[_.]|__|[-]*/
tag := /[\w][\w.-]{0,127}/
digest := digest-algorithm ":" digest-hex
digest-algorithm := digest-algorithm-component [ digest-algorithm-separator digest-algorithm-component ]*
digest-algorithm-separator := /[+.-_]/
digest-algorithm-component := /[A-Za-z][A-Za-z0-9]*/
digest-hex := /[0-9a-fA-F]{32,}/ ; At least 128 bit digest value
identifier := /[a-f0-9]{64}/
short-identifier := /[a-f0-9]{6,64}/
EXAMPLES
registry.hub.docker.com/library/busybox@sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa
registry.hub.docker.com/seaplane/busybox:latest"#;