Merge pull request #55254 from mtaufen/iterative-manifest-url-header

cmd/kubelet/app/options/options.go

@@ -371,7 +371,7 @@ func AddKubeletConfigFlags(fs *pflag.FlagSet, c *kubeletconfig.KubeletConfigurat
 	fs.DurationVar(&c.FileCheckFrequency.Duration, "file-check-frequency", c.FileCheckFrequency.Duration, "Duration between checking config files for new data")
 	fs.DurationVar(&c.HTTPCheckFrequency.Duration, "http-check-frequency", c.HTTPCheckFrequency.Duration, "Duration between checking http for new data")
 	fs.StringVar(&c.ManifestURL, "manifest-url", c.ManifestURL, "URL for accessing the container manifest")
-	fs.Var(flag.ColonSeparatedMultimapStringString(c.ManifestURLHeader), "manifest-url-header", "Comma-separated list of HTTP headers to use when accessing the manifest URL. Multiple headers with the same name will be added in the same order provided. For example: `a:hello,b:again,c:world,b:beautiful`")
+	fs.Var(flag.NewColonSeparatedMultimapStringString(&c.ManifestURLHeader), "manifest-url-header", "Comma-separated list of HTTP headers to use when accessing the manifest URL. Multiple headers with the same name will be added in the same order provided. This flag can be repeatedly invoked. For example: `--manifest-url-header 'a:hello,b:again,c:world' --manifest-url-header 'b:beautiful'`")
 	fs.BoolVar(&c.EnableServer, "enable-server", c.EnableServer, "Enable the Kubelet's server")
 	fs.Var(componentconfig.IPVar{Val: &c.Address}, "address", "The IP address for the Kubelet to serve on (set to 0.0.0.0 for all interfaces)")
 	fs.Int32Var(&c.Port, "port", c.Port, "The port for the Kubelet to serve on.")

pkg/kubelet/apis/kubeletconfig/v1alpha1/defaults.go

@@ -231,9 +231,6 @@ func SetDefaults_KubeletConfiguration(obj *KubeletConfiguration) {
 	if obj.EnforceNodeAllocatable == nil {
 		obj.EnforceNodeAllocatable = defaultNodeAllocatableEnforcement
 	}
-	if obj.ManifestURLHeader == nil {
-		obj.ManifestURLHeader = make(map[string][]string)
-	}
 }
 
 func boolVar(b bool) *bool {

staging/src/k8s.io/apiserver/pkg/util/flag/colon_separated_multimap_string_string.go

@@ -28,13 +28,30 @@ import (
 // slice of strings associated with that key. Items in the list associated with a given
 // key will appear in the order provided.
 // For example: `a:hello,b:again,c:world,b:beautiful` results in `{"a": ["hello"], "b": ["again", "beautiful"], "c": ["world"]}`
-type ColonSeparatedMultimapStringString map[string][]string
+// The first call to Set will clear the map before adding entries; subsequent calls will simply append to the map.
+// This makes it possible to override default values with a command-line option rather than appending to defaults,
+// while still allowing the distribution of key-value pairs across multiple flag invocations.
+// For example: `--flag "a:hello" --flag "b:again" --flag "b:beautiful" --flag "c:world"` results in `{"a": ["hello"], "b": ["again", "beautiful"], "c": ["world"]}`
+type ColonSeparatedMultimapStringString struct {
+	Multimap    *map[string][]string
+	initialized bool // set to true after the first Set call
+}
+
+// NewColonSeparatedMultimapStringString takes a pointer to a map[string][]string and returns the
+// ColonSeparatedMultimapStringString flag parsing shim for that map.
+func NewColonSeparatedMultimapStringString(m *map[string][]string) *ColonSeparatedMultimapStringString {
+	return &ColonSeparatedMultimapStringString{Multimap: m}
+}
 
 // Set implements github.com/spf13/pflag.Value
-func (m ColonSeparatedMultimapStringString) Set(value string) error {
-	// clear old values
-	for k := range m {
-		delete(m, k)
+func (m *ColonSeparatedMultimapStringString) Set(value string) error {
+	if m.Multimap == nil {
+		return fmt.Errorf("no target (nil pointer to map[string][]string)")
+	}
+	if !m.initialized || *m.Multimap == nil {
+		// clear default values, or allocate if no existing map
+		*m.Multimap = make(map[string][]string)
+		m.initialized = true
 	}
 	for _, pair := range strings.Split(value, ",") {
 		if len(pair) == 0 {
@@ -46,19 +63,19 @@ func (m ColonSeparatedMultimapStringString) Set(value string) error {
 		}
 		k := strings.TrimSpace(kv[0])
 		v := strings.TrimSpace(kv[1])
-		m[k] = append(m[k], v)
+		(*m.Multimap)[k] = append((*m.Multimap)[k], v)
 	}
 	return nil
 }
 
 // String implements github.com/spf13/pflag.Value
-func (m ColonSeparatedMultimapStringString) String() string {
+func (m *ColonSeparatedMultimapStringString) String() string {
 	type kv struct {
 		k string
 		v string
 	}
-	kvs := make([]kv, 0, len(m))
-	for k, vs := range m {
+	kvs := make([]kv, 0, len(*m.Multimap))
+	for k, vs := range *m.Multimap {
 		for i := range vs {
 			kvs = append(kvs, kv{k: k, v: vs[i]})
 		}
@@ -75,6 +92,11 @@ func (m ColonSeparatedMultimapStringString) String() string {
 }
 
 // Type implements github.com/spf13/pflag.Value
-func (m ColonSeparatedMultimapStringString) Type() string {
+func (m *ColonSeparatedMultimapStringString) Type() string {
 	return "colonSeparatedMultimapStringString"
 }
+
+// Empty implements OmitEmpty
+func (m *ColonSeparatedMultimapStringString) Empty() bool {
+	return len(*m.Multimap) == 0
+}