Add rewrites map to mirrors struct, initialize empty map for k3d side…

… of config

- This will allow for passing through mirror config via the config block
- This wont allow rewrites to be configured as part of a k3d config file, only via registries.yaml (inline or not)

pkg/client/registry.go

@@ -191,6 +191,7 @@ func RegistryConnectNetworks(ctx context.Context, runtime runtimes.Runtime, regi
 // RegistryGenerateK3sConfig generates the k3s specific registries.yaml configuration for multiple registries
 func RegistryGenerateK3sConfig(ctx context.Context, registries []*k3d.Registry) (*k3s.Registry, error) {
 	regConf := &k3s.Registry{}
+	rewritesConf := make(map[string]string)
 
 	for _, reg := range registries {
 		internalAddress := fmt.Sprintf("%s:%s", reg.Host, reg.ExposureOpts.Port.Port())
@@ -205,18 +206,21 @@ func RegistryGenerateK3sConfig(ctx context.Context, registries []*k3d.Registry)
 			Endpoints: []string{
 				fmt.Sprintf("http://%s", internalAddress),
 			},
+			Rewrites: rewritesConf,
 		}
 
 		regConf.Mirrors[internalAddress] = k3s.Mirror{
 			Endpoints: []string{
 				fmt.Sprintf("http://%s", internalAddress),
 			},
+			Rewrites: rewritesConf, // stub out rewrites so we dont override with nil
 		}
 
 		if reg.Options.Proxy.RemoteURL != "" {
 			regConf.Mirrors[reg.Options.Proxy.RemoteURL] = k3s.Mirror{
 				Endpoints: []string{fmt.Sprintf("http://%s", internalAddress)},
 			}
+
 		}
 	}
 

pkg/types/k3s/registry.go

@@ -33,6 +33,10 @@ type Mirror struct {
 	// with host specified.
 	// The scheme, host and path from the endpoint URL will be used.
 	Endpoints []string `toml:"endpoint" json:"endpoint"`
+	// Rewrites are rewrite rules for a registry. Rewrites change the tag of an
+	// image based on a regular expression. When using mirrors this can be helpful
+	// structure / organization of the mirror differs to the upstream.
+	Rewrites map[string]string `toml:"rewrite" json:"rewrite"`
 }
 
 // AuthConfig contains the config related to authentication to a specific registry