move name generation to generic api server storage helpers

staging/src/k8s.io/apiserver/pkg/storage/names/generate.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package names
+
+import (
+	"fmt"
+
+	utilrand "k8s.io/apimachinery/pkg/util/rand"
+)
+
+// NameGenerator generates names for objects. Some backends may have more information
+// available to guide selection of new names and this interface hides those details.
+type NameGenerator interface {
+	// GenerateName generates a valid name from the base name, adding a random suffix to the
+	// the base. If base is valid, the returned name must also be valid. The generator is
+	// responsible for knowing the maximum valid name length.
+	GenerateName(base string) string
+}
+
+// simpleNameGenerator generates random names.
+type simpleNameGenerator struct{}
+
+// SimpleNameGenerator is a generator that returns the name plus a random suffix of five alphanumerics
+// when a name is requested. The string is guaranteed to not exceed the length of a standard Kubernetes
+// name (63 characters)
+var SimpleNameGenerator NameGenerator = simpleNameGenerator{}
+
+const (
+	// TODO: make this flexible for non-core resources with alternate naming rules.
+	maxNameLength          = 63
+	randomLength           = 5
+	maxGeneratedNameLength = maxNameLength - randomLength
+)
+
+func (simpleNameGenerator) GenerateName(base string) string {
+	if len(base) > maxGeneratedNameLength {
+		base = base[:maxGeneratedNameLength]
+	}
+	return fmt.Sprintf("%s%s", base, utilrand.String(randomLength))
+}

staging/src/k8s.io/apiserver/pkg/storage/names/generate_test.go

@@ -0,0 +1,79 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package names
+
+import (
+	"strings"
+	"testing"
+)
+
+type nameGeneratorFunc func(base string) string
+
+func (fn nameGeneratorFunc) GenerateName(base string) string {
+	return fn(base)
+}
+
+func TestGenerateName(t *testing.T) {
+	testCases := []struct {
+		meta ObjectMeta
+
+		base     string
+		returned string
+	}{
+		{
+			returned: "",
+		},
+		{
+			meta: ObjectMeta{
+				GenerateName: "test",
+			},
+			base:     "test",
+			returned: "test",
+		},
+		{
+			meta: ObjectMeta{
+				Name:         "foo",
+				GenerateName: "test",
+			},
+			base:     "test",
+			returned: "foo",
+		},
+	}
+
+	for i, testCase := range testCases {
+		GenerateName(nameGeneratorFunc(func(base string) string {
+			if base != testCase.base {
+				t.Errorf("%d: unexpected call with base", i)
+			}
+			return "test"
+		}), &testCase.meta)
+		expect := testCase.returned
+		if expect != testCase.meta.Name {
+			t.Errorf("%d: unexpected name: %#v", i, testCase.meta)
+		}
+	}
+}
+
+func TestSimpleNameGenerator(t *testing.T) {
+	meta := &ObjectMeta{
+		GenerateName: "foo",
+	}
+	GenerateName(SimpleNameGenerator, meta)
+	if !strings.HasPrefix(meta.Name, "foo") || meta.Name == "foo" {
+		t.Errorf("unexpected name: %#v", meta)
+	}
+}