*: add support for subresources

Author: ericchiang

README.md

@@ -204,7 +204,16 @@ l := new(k8s.LabelSelector)
 l.Eq("tier", "production")
 l.In("app", "database", "frontend")
 
-pods, err := client.CoreV1().ListPods(ctx, client.Namespace, l.Selector())
+var pods corev1.PodList
+err := client.List(ctx, "custom-namespace", &pods, l.Selector())
+```
+
+### Subresources
+
+Access subresources using the `Subresource` option.
+
+```go
+err := client.Update(ctx, &pod, k8s.Subresource("status"))
 ```
 
 ### Creating out-of-cluster clients

client.go

@@ -37,7 +37,6 @@ import (
 	"net"
 	"net/http"
 	"os"
-	"strconv"
 	"time"
 
 	"golang.org/x/net/http2"
@@ -114,52 +113,6 @@ func (c *Client) newRequest(ctx context.Context, verb, url string, body io.Reade
 	return req.WithContext(ctx), nil
 }
 
-// Option represents optional call parameters, such as label selectors.
-type Option interface {
-	queryParam() (key, val string)
-}
-
-type queryParam struct {
-	paramName  string
-	paramValue string
-}
-
-func (o queryParam) queryParam() (string, string) {
-	return o.paramName, o.paramValue
-}
-
-// QueryParam can be used to manually set a URL query parameter by name.
-func QueryParam(name, value string) Option {
-	return queryParam{
-		paramName:  name,
-		paramValue: value,
-	}
-}
-
-type resourceVersionOption string
-
-func (r resourceVersionOption) queryParam() (string, string) {
-	return "resourceVersion", string(r)
-}
-
-// ResourceVersion causes watch operations to only show changes since
-// a particular version of a resource.
-func ResourceVersion(resourceVersion string) Option {
-	return resourceVersionOption(resourceVersion)
-}
-
-type timeoutSeconds string
-
-func (t timeoutSeconds) queryParam() (string, string) {
-	return "timeoutSeconds", string(t)
-}
-
-// Timeout declares the timeout for list and watch operations. Timeout
-// is only accurate to the second.
-func Timeout(d time.Duration) Option {
-	return timeoutSeconds(strconv.FormatInt(int64(d/time.Second), 10))
-}
-
 // NewClient initializes a client from a client config.
 func NewClient(config *Config) (*Client, error) {
 	if len(config.Contexts) == 0 {

client_test.go

@@ -92,6 +92,10 @@ func TestListNodes(t *testing.T) {
 	if err := client.List(context.TODO(), "", &nodes); err != nil {
 		t.Fatal(err)
 	}
+	if len(nodes.Items) == 0 {
+		t.Skip("no nodes in cluster")
+	}
+
 	for _, node := range nodes.Items {
 		if node.Metadata.Annotations == nil {
 			node.Metadata.Annotations = map[string]string{}
@@ -111,6 +115,24 @@ func TestWithNamespace(t *testing.T) {
 	withNamespace(t, func(client *k8s.Client, namespace string) {})
 }
 
+func TestUpdateNamespaceStatus(t *testing.T) {
+	withNamespace(t, func(client *k8s.Client, namespace string) {
+		var ns corev1.Namespace
+		if err := client.Get(context.TODO(), "", namespace, &ns); err != nil {
+			t.Errorf("get namespace: %v", err)
+			return
+		}
+
+		if err := client.Update(context.TODO(), &ns, k8s.Subresource("status")); err != nil {
+			t.Errorf("update namespace status subresource: %v", err)
+		}
+
+		if err := client.Update(context.TODO(), &ns, k8s.Subresource("idontexist")); err == nil {
+			t.Errorf("updated invalid subresource")
+		}
+	})
+}
+
 func TestCreateConfigMap(t *testing.T) {
 	withNamespace(t, func(client *k8s.Client, namespace string) {
 		cm := &corev1.ConfigMap{

labels.go

@@ -28,14 +28,8 @@ type LabelSelector struct {
 	stmts []string
 }
 
-type labelSelectorOption string
-
-func (l labelSelectorOption) queryParam() (string, string) {
-	return "labelSelector", string(l)
-}
-
 func (l *LabelSelector) Selector() Option {
-	return labelSelectorOption(l.String())
+	return queryParam{"labelSelector", l.String()}
 }
 
 func (l *LabelSelector) String() string {

resource.go

@@ -6,11 +6,70 @@ import (
 	"net/url"
 	"path"
 	"reflect"
+	"strconv"
 	"strings"
+	"time"
 
 	metav1 "github.com/ericchiang/k8s/apis/meta/v1"
 )
 
+// Option represents optional call parameters, such as label selectors.
+type Option interface {
+	updateURL(base string, v url.Values) string
+}
+
+type queryParam struct {
+	paramName  string
+	paramValue string
+}
+
+func (o queryParam) updateURL(base string, v url.Values) string {
+	v.Set(o.paramName, o.paramValue)
+	return base
+}
+
+// QueryParam can be used to manually set a URL query parameter by name.
+func QueryParam(name, value string) Option {
+	return queryParam{
+		paramName:  name,
+		paramValue: value,
+	}
+}
+
+// ResourceVersion causes watch operations to only show changes since
+// a particular version of a resource.
+func ResourceVersion(resourceVersion string) Option {
+	return queryParam{"resourceVersion", resourceVersion}
+}
+
+// Timeout declares the timeout for list and watch operations. Timeout
+// is only accurate to the second.
+func Timeout(d time.Duration) Option {
+	return queryParam{
+		"timeoutSeconds",
+		strconv.FormatInt(int64(d/time.Second), 10),
+	}
+}
+
+// Subresource is a way to interact with a part of an API object without needing
+// permissions on the entire resource. For example, a node isn't able to modify
+// a pod object, but can update the "pods/status" subresource.
+//
+// Common subresources are "status" and "scale".
+//
+// See https://kubernetes.io/docs/reference/api-concepts/
+func Subresource(name string) Option {
+	return subresource{name}
+}
+
+type subresource struct {
+	name string
+}
+
+func (s subresource) updateURL(base string, v url.Values) string {
+	return base + "/" + s.name
+}
+
 type resourceType struct {
 	apiGroup   string
 	apiVersion string
@@ -74,8 +133,10 @@ func urlFor(endpoint, apiGroup, apiVersion, namespace, resource, name string, op
 
 	v := url.Values{}
 	for _, option := range options {
-		key, val := option.queryParam()
-		v.Set(key, val)
+		e = option.updateURL(e, v)
+	}
+	if len(v) == 0 {
+		return e
 	}
 	return e + "?" + v.Encode()
 }

resource_test.go

@@ -2,6 +2,7 @@ package k8s
 
 import (
 	"testing"
+	"time"
 
 	metav1 "github.com/ericchiang/k8s/apis/meta/v1"
 )
@@ -97,6 +98,49 @@ func TestResourceURL(t *testing.T) {
 			withName: true,
 			want:     "https://example.com/apis/apps/v1beta2/namespaces/my-namespace/deployments/my-deployment",
 		},
+		{
+			name:     "deployment-with-subresource",
+			endpoint: "https://example.com",
+			resource: &Deployment{
+				Metadata: &metav1.ObjectMeta{
+					Namespace: String("my-namespace"),
+					Name:      String("my-deployment"),
+				},
+			},
+			withName: true,
+			options: []Option{
+				Subresource("status"),
+			},
+			want: "https://example.com/apis/apps/v1beta2/namespaces/my-namespace/deployments/my-deployment/status",
+		},
+		{
+			name:     "pod-with-timeout",
+			endpoint: "https://example.com",
+			resource: &Pod{
+				Metadata: &metav1.ObjectMeta{
+					Namespace: String("my-namespace"),
+					Name:      String("my-pod"),
+				},
+			},
+			options: []Option{
+				Timeout(time.Minute),
+			},
+			want: "https://example.com/api/v1/namespaces/my-namespace/pods?timeoutSeconds=60",
+		},
+		{
+			name:     "pod-with-resource-version",
+			endpoint: "https://example.com",
+			resource: &Pod{
+				Metadata: &metav1.ObjectMeta{
+					Namespace: String("my-namespace"),
+					Name:      String("my-pod"),
+				},
+			},
+			options: []Option{
+				ResourceVersion("foo"),
+			},
+			want: "https://example.com/api/v1/namespaces/my-namespace/pods?resourceVersion=foo",
+		},
 	}
 
 	for _, test := range tests {