IsValidTargetKey checks if a string is a valid installation target key.

IsValidTargetVal checks if a string is a valid installtion target value.

NewTarget creates a new target with the specified version and options.

Normalize attaches the expected `v` prefix to a version string if the supplied version is currently invalid, and attaching the prefix makes it valid.

SecurityPatch sets the security-patch=yes label if true.

SecurityPatchAlts appends version strings to the security-patch-alts label.

LabelSecurityPatch indicates that a release is a security patch when set to 'yes'.

LabelSecurityPatchAlts lists alternative versions that provide the same security fixes.

LabelVersion is the only required label for an installation target and must be valid go-style semver.

UnitConfigDir is the configuration directory of the teleport-upgrade unit.

Visitor is a helper for aggregating information about observed targets.

Target is a description of an available installation target.

TargetOption is a functional option for setting additional target fields during construction.