devmapper: add snapshotter config

Signed-off-by: Maksym Pavlenko <makpav@amazon.com>

snapshots/devmapper/config_test.go

@@ -0,0 +1,122 @@
+/*
+   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 devmapper
+
+import (
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/BurntSushi/toml"
+	"github.com/hashicorp/go-multierror"
+	"gotest.tools/assert"
+	is "gotest.tools/assert/cmp"
+)
+
+func TestLoadConfig(t *testing.T) {
+	expected := Config{
+		RootPath:       "/tmp",
+		PoolName:       "test",
+		DataDevice:     "/dev/loop0",
+		MetadataDevice: "/dev/loop1",
+		DataBlockSize:  "1mb",
+		BaseImageSize:  "128Mb",
+	}
+
+	file, err := ioutil.TempFile("", "devmapper-config-")
+	assert.NilError(t, err)
+
+	encoder := toml.NewEncoder(file)
+	err = encoder.Encode(&expected)
+	assert.NilError(t, err)
+
+	defer func() {
+		err := file.Close()
+		assert.NilError(t, err)
+
+		err = os.Remove(file.Name())
+		assert.NilError(t, err)
+	}()
+
+	loaded, err := LoadConfig(file.Name())
+	assert.NilError(t, err)
+
+	assert.Equal(t, loaded.RootPath, expected.RootPath)
+	assert.Equal(t, loaded.PoolName, expected.PoolName)
+	assert.Equal(t, loaded.DataDevice, expected.DataDevice)
+	assert.Equal(t, loaded.MetadataDevice, expected.MetadataDevice)
+	assert.Equal(t, loaded.DataBlockSize, expected.DataBlockSize)
+	assert.Equal(t, loaded.BaseImageSize, expected.BaseImageSize)
+
+	assert.Assert(t, loaded.DataBlockSizeSectors == 1*1024*1024/512)
+	assert.Assert(t, loaded.BaseImageSizeBytes == 128*1024*1024)
+}
+
+func TestLoadConfigInvalidPath(t *testing.T) {
+	_, err := LoadConfig("")
+	assert.Equal(t, os.ErrNotExist, err)
+
+	_, err = LoadConfig("/dev/null")
+	assert.Assert(t, err != nil)
+}
+
+func TestParseInvalidData(t *testing.T) {
+	config := Config{
+		DataBlockSize: "x",
+		BaseImageSize: "y",
+	}
+
+	err := config.parse()
+	assert.Assert(t, err != nil)
+
+	multErr := (err).(*multierror.Error)
+	assert.Assert(t, is.Len(multErr.Errors, 2))
+
+	assert.Assert(t, strings.Contains(multErr.Errors[0].Error(), "failed to parse data block size: \"x\""))
+	assert.Assert(t, strings.Contains(multErr.Errors[1].Error(), "failed to parse base image size: \"y\""))
+}
+
+func TestFieldValidation(t *testing.T) {
+	config := &Config{DataBlockSizeSectors: 1}
+	err := config.Validate()
+	assert.Assert(t, err != nil)
+
+	multErr := (err).(*multierror.Error)
+	assert.Assert(t, is.Len(multErr.Errors, 8))
+
+	assert.Assert(t, multErr.Errors[0] != nil, "pool_name is empty")
+	assert.Assert(t, multErr.Errors[1] != nil, "root_path is empty")
+	assert.Assert(t, multErr.Errors[2] != nil, "base_image_size is empty")
+	assert.Assert(t, multErr.Errors[3] != nil, "data_device is empty")
+	assert.Assert(t, multErr.Errors[4] != nil, "meta_device is empty")
+	assert.Assert(t, multErr.Errors[5] != nil, "data_block_size is empty")
+
+	assert.Equal(t, multErr.Errors[6], errInvalidBlockSize)
+	assert.Equal(t, multErr.Errors[7], errInvalidBlockAlignment)
+}
+
+func TestExistingPoolFieldValidation(t *testing.T) {
+	config := &Config{
+		PoolName:      "test",
+		RootPath:      "test",
+		BaseImageSize: "10mb",
+	}
+
+	err := config.Validate()
+	assert.NilError(t, err)
+}