cloudinit/config/validate/validate.go

// 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 validate

import (
	"errors"
	"fmt"
	"regexp"
	"strconv"
	"strings"

	"github.com/coreos/coreos-cloudinit/config"

	"github.com/coreos/coreos-cloudinit/Godeps/_workspace/src/github.com/coreos/yaml"
)

var (
	yamlLineError = regexp.MustCompile(`^YAML error: line (?P<line>[[:digit:]]+): (?P<msg>.*)$`)
	yamlError     = regexp.MustCompile(`^YAML error: (?P<msg>.*)$`)
)

// Validate runs a series of validation tests against the given userdata and
// returns a report detailing all of the issues. Presently, only cloud-configs
// can be validated.
func Validate(userdataBytes []byte) (Report, error) {
	switch {
	case len(userdataBytes) == 0:
		return Report{}, nil
	case config.IsScript(string(userdataBytes)):
		return Report{}, nil
	case config.IsCloudConfig(string(userdataBytes)):
		return validateCloudConfig(userdataBytes, Rules)
	default:
		return Report{entries: []Entry{
			Entry{kind: entryError, message: `must be "#cloud-config" or begin with "#!"`, line: 1},
		}}, nil
	}
}

// validateCloudConfig runs all of the validation rules in Rules and returns
// the resulting report and any errors encountered.
func validateCloudConfig(config []byte, rules []rule) (report Report, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = fmt.Errorf("%v", r)
		}
	}()

	c, err := parseCloudConfig(config, &report)
	if err != nil {
		return report, err
	}

	c = normalizeNodeNames(c, &report)
	for _, r := range rules {
		r(c, &report)
	}
	return report, nil
}

// parseCloudConfig parses the provided config into a node structure and logs
// any parsing issues into the provided report. Unrecoverable errors are
// returned as an error.
func parseCloudConfig(config []byte, report *Report) (n node, err error) {
	var raw map[interface{}]interface{}
	if err := yaml.Unmarshal(config, &raw); err != nil {
		matches := yamlLineError.FindStringSubmatch(err.Error())
		if len(matches) == 3 {
			line, err := strconv.Atoi(matches[1])
			if err != nil {
				return n, err
			}
			msg := matches[2]
			report.Error(line, msg)
			return n, nil
		}

		matches = yamlError.FindStringSubmatch(err.Error())
		if len(matches) == 2 {
			report.Error(1, matches[1])
			return n, nil
		}

		return n, errors.New("couldn't parse yaml error")
	}

	return NewNode(raw, NewContext(config)), nil
}

// normalizeNodeNames replaces all occurences of '-' with '_' within key names
// and makes a note of each replacement in the report.
func normalizeNodeNames(node node, report *Report) node {
	if strings.Contains(node.name, "-") {
		// TODO(crawford): Enable this message once the new validator hits stable.
		//report.Info(node.line, fmt.Sprintf("%q uses '-' instead of '_'", node.name))
		node.name = strings.Replace(node.name, "-", "_", -1)
	}
	for i := range node.children {
		node.children[i] = normalizeNodeNames(node.children[i], report)
	}
	return node
}