move coreos-cloudinit into config/cloudinit

Signed-off-by: Sven Dowideit <SvenDowideit@home.org.au>

config/cloudinit/system/env_file.go

@@ -0,0 +1,114 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// 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 system
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"regexp"
+	"sort"
+)
+
+type EnvFile struct {
+	Vars map[string]string
+	// mask File.Content, it shouldn't be used.
+	Content interface{} `json:"-" yaml:"-"`
+	*File
+}
+
+// only allow sh compatible identifiers
+var validKey = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)
+
+// match each line, optionally capturing valid identifiers, discarding dos line endings
+var lineLexer = regexp.MustCompile(`(?m)^((?:([a-zA-Z0-9_]+)=)?.*?)\r?\n`)
+
+// mergeEnvContents: Update the existing file contents with new values,
+// preserving variable ordering and all content this code doesn't understand.
+// All new values are appended to the bottom of the old, sorted by key.
+func mergeEnvContents(old []byte, pending map[string]string) []byte {
+	var buf bytes.Buffer
+	var match [][]byte
+
+	// it is awkward for the regex to handle a missing newline gracefully
+	if len(old) != 0 && !bytes.HasSuffix(old, []byte{'\n'}) {
+		old = append(old, byte('\n'))
+	}
+
+	for _, match = range lineLexer.FindAllSubmatch(old, -1) {
+		key := string(match[2])
+		if value, ok := pending[key]; ok {
+			fmt.Fprintf(&buf, "%s=%s\n", key, value)
+			delete(pending, key)
+		} else {
+			fmt.Fprintf(&buf, "%s\n", match[1])
+		}
+	}
+
+	for _, key := range keys(pending) {
+		value := pending[key]
+		fmt.Fprintf(&buf, "%s=%s\n", key, value)
+	}
+
+	return buf.Bytes()
+}
+
+// WriteEnvFile updates an existing env `KEY=value` formated file with
+// new values provided in EnvFile.Vars; File.Content is ignored.
+// Existing ordering and any unknown formatting such as comments are
+// preserved. If no changes are required the file is untouched.
+func WriteEnvFile(ef *EnvFile, root string) error {
+	// validate new keys, mergeEnvContents uses pending to track writes
+	pending := make(map[string]string, len(ef.Vars))
+	for key, value := range ef.Vars {
+		if !validKey.MatchString(key) {
+			return fmt.Errorf("Invalid name %q for %s", key, ef.Path)
+		}
+		pending[key] = value
+	}
+
+	if len(pending) == 0 {
+		return nil
+	}
+
+	oldContent, err := ioutil.ReadFile(path.Join(root, ef.Path))
+	if err != nil {
+		if os.IsNotExist(err) {
+			oldContent = []byte{}
+		} else {
+			return err
+		}
+	}
+
+	newContent := mergeEnvContents(oldContent, pending)
+	if bytes.Equal(oldContent, newContent) {
+		return nil
+	}
+
+	ef.File.Content = string(newContent)
+	_, err = WriteFile(ef.File, root)
+	return err
+}
+
+// keys returns the keys of a map in sorted order
+func keys(m map[string]string) (s []string) {
+	for k := range m {
+		s = append(s, k)
+	}
+	sort.Strings(s)
+	return
+}