EnsureSemver adds the 'v' prefix if needed and ensures the provided version is semver-compliant.

NewProxyVersionGetter creates a ProxyVersionGetter from a webclient.

NewStaticGetter creates a StaticGetter.

ValidVersionChange receives the current version and the candidate next version and evaluates if the version transition is valid.

BasicHTTPVersionGetter gets the version from an HTTP response containing only the version.

NoNewVersionError indicates that no new version was found and the controller did not reconcile.

ProxyVersionGetter gets the target version from the Teleport Proxy Service /find endpoint, as specified in the RFD-184: https://github.com/gravitational/teleport/blob/master/rfd/0184-agent-auto-updates.md The Getter returns trace.NotImplementedErr when running against a proxy that does not seem to expose automatic update instructions over the /find endpoint (proxy too old).

StaticGetter is a fake version.Getter that return a static answer.

Getter gets the target image version for an external source.

FailoverGetter wraps multiple Getters and tries them sequentially.