Move labels to pkg/labels

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/labels/labels.go

@@ -0,0 +1,29 @@
+/*
+   Copyright The containerd 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 labels
+
+// LabelUncompressed is added to compressed layer contents.
+// The value is digest of the uncompressed content.
+const LabelUncompressed = "containerd.io/uncompressed"
+
+// LabelSharedNamespace is added to a namespace to allow that namespaces
+// contents to be shared.
+const LabelSharedNamespace = "containerd.io/namespace.shareable"
+
+// LabelDistributionSource is added to content to indicate its origin.
+// e.g., "containerd.io/distribution.source.docker.io=library/redis"
+const LabelDistributionSource = "containerd.io/distribution.source"

pkg/labels/validate.go

@@ -0,0 +1,41 @@
+/*
+   Copyright The containerd 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 labels
+
+import (
+	"fmt"
+
+	"github.com/containerd/containerd/v2/pkg/errdefs"
+)
+
+const (
+	maxSize = 4096
+	// maximum length of key portion of error message if len of key + len of value > maxSize
+	keyMaxLen = 64
+)
+
+// Validate a label's key and value are under 4096 bytes
+func Validate(k, v string) error {
+	total := len(k) + len(v)
+	if total > maxSize {
+		if len(k) > keyMaxLen {
+			k = k[:keyMaxLen]
+		}
+		return fmt.Errorf("label key and value length (%d bytes) greater than maximum size (%d bytes), key: %s: %w", total, maxSize, k, errdefs.ErrInvalidArgument)
+	}
+	return nil
+}

pkg/labels/validate_test.go

@@ -0,0 +1,80 @@
+/*
+   Copyright The containerd 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 labels
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/containerd/containerd/v2/pkg/errdefs"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValidLabels(t *testing.T) {
+	shortStr := "s"
+	longStr := strings.Repeat("s", maxSize-1)
+
+	for key, value := range map[string]string{
+		"some":   "value",
+		shortStr: longStr,
+	} {
+		if err := Validate(key, value); err != nil {
+			t.Fatalf("unexpected error: %v != nil", err)
+		}
+	}
+}
+
+func TestInvalidLabels(t *testing.T) {
+	addOneStr := "s"
+	maxSizeStr := strings.Repeat("s", maxSize)
+
+	for key, value := range map[string]string{
+		maxSizeStr: addOneStr,
+	} {
+		if err := Validate(key, value); err == nil {
+			t.Fatal("expected invalid error")
+		} else if !errdefs.IsInvalidArgument(err) {
+			t.Fatal("error should be an invalid label error")
+		}
+	}
+}
+
+func TestLongKey(t *testing.T) {
+	key := strings.Repeat("s", keyMaxLen+1)
+	value := strings.Repeat("v", maxSize-len(key))
+
+	err := Validate(key, value)
+	assert.Equal(t, err, nil)
+
+	key = strings.Repeat("s", keyMaxLen+12)
+	value = strings.Repeat("v", maxSize-len(key)+1)
+
+	err = Validate(key, value)
+	assert.ErrorIs(t, err, errdefs.ErrInvalidArgument)
+
+	key = strings.Repeat("s", keyMaxLen-1)
+	value = strings.Repeat("v", maxSize-len(key))
+
+	err = Validate(key, value)
+	assert.Equal(t, err, nil)
+
+	key = strings.Repeat("s", keyMaxLen-1)
+	value = strings.Repeat("v", maxSize-len(key)-1)
+
+	err = Validate(key, value)
+	assert.Equal(t, err, nil)
+}