environs/config.go

// Copyright 2011, 2012, 2013 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.

package environs

import (
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"

	"launchpad.net/goyaml"
	"launchpad.net/loggo"

	"launchpad.net/juju-core/environs/config"
)

var logger = loggo.GetLogger("juju.environs")

// environ holds information about one environment.
type environ struct {
	config *config.Config
	err    error // an error if the config data could not be parsed.
}

// Environs holds information about each named environment
// in an environments.yaml file.
type Environs struct {
	Default  string // The name of the default environment.
	environs map[string]environ
}

// Names returns the list of environment names.
func (e *Environs) Names() (names []string) {
	for name := range e.environs {
		names = append(names, name)
	}
	return
}

// providers maps from provider type to EnvironProvider for
// each registered provider type.
var providers = make(map[string]EnvironProvider)

// RegisterProvider registers a new environment provider. Name gives the name
// of the provider, and p the interface to that provider.
//
// RegisterProvider will panic if the same provider name is registered more than
// once.
func RegisterProvider(name string, p EnvironProvider) {
	if providers[name] != nil {
		panic(fmt.Errorf("juju: duplicate provider name %q", name))
	}
	providers[name] = p
}

// Provider returns the previously registered provider with the given type.
func Provider(typ string) (EnvironProvider, error) {
	p, ok := providers[typ]
	if !ok {
		return nil, fmt.Errorf("no registered provider for %q", typ)
	}
	return p, nil
}

// ReadEnvironsBytes parses the contents of an environments.yaml file
// and returns its representation. An environment with an unknown type
// will only generate an error when New is called for that environment.
// Attributes for environments with known types are checked.
func ReadEnvironsBytes(data []byte) (*Environs, error) {
	var raw struct {
		Default      string
		Environments map[string]map[string]interface{}
	}
	err := goyaml.Unmarshal(data, &raw)
	if err != nil {
		return nil, err
	}

	if raw.Default != "" && raw.Environments[raw.Default] == nil {
		return nil, fmt.Errorf("default environment %q does not exist", raw.Default)
	}
	if raw.Default == "" {
		// If there's a single environment, then we get the default
		// automatically.
		if len(raw.Environments) == 1 {
			for name := range raw.Environments {
				raw.Default = name
				break
			}
		}
	}

	environs := make(map[string]environ)
	for name, attrs := range raw.Environments {
		kind, _ := attrs["type"].(string)
		if kind == "" {
			environs[name] = environ{
				err: fmt.Errorf("environment %q has no type", name),
			}
			continue
		}
		p := providers[kind]
		if p == nil {
			environs[name] = environ{
				err: fmt.Errorf("environment %q has an unknown provider type %q", name, kind),
			}
			continue
		}
		// store the name of the this environment in the config itself
		// so that providers can see it.
		attrs["name"] = name
		cfg, err := config.New(attrs)
		if err != nil {
			environs[name] = environ{
				err: fmt.Errorf("error parsing environment %q: %v", name, err),
			}
			continue
		}
		environs[name] = environ{config: cfg}
	}
	return &Environs{raw.Default, environs}, nil
}

func environsPath(path string) string {
	if path == "" {
		path = config.JujuHomePath("environments.yaml")
	}
	return path
}

// ReadEnvirons reads the juju environments.yaml file
// and returns the result of running ParseEnvironments
// on the file's contents.
// If path is empty, $HOME/.juju/environments.yaml is used.
func ReadEnvirons(path string) (*Environs, error) {
	environsFilepath := environsPath(path)
	data, err := ioutil.ReadFile(environsFilepath)
	if err != nil {
		return nil, err
	}
	e, err := ReadEnvironsBytes(data)
	if err != nil {
		return nil, fmt.Errorf("cannot parse %q: %v", environsFilepath, err)
	}
	return e, nil
}

// WriteEnvirons creates a new juju environments.yaml file with the specified contents.
func WriteEnvirons(path string, fileContents string) (string, error) {
	environsFilepath := environsPath(path)
	environsDir := filepath.Dir(environsFilepath)
	var info os.FileInfo
	var err error
	if info, err = os.Lstat(environsDir); os.IsNotExist(err) {
		if err = os.MkdirAll(environsDir, 0700); err != nil {
			return "", err
		}
	} else if err != nil {
		return "", err
	} else if info.Mode().Perm() != 0700 {
		logger.Warningf("permission of %q is %q", environsDir, info.Mode().Perm())
	}
	if err := ioutil.WriteFile(environsFilepath, []byte(fileContents), 0600); err != nil {
		return "", err
	}
	// WriteFile does not change permissions of existing files.
	if err := os.Chmod(environsFilepath, 0600); err != nil {
		return "", err
	}
	return environsFilepath, nil
}

// BootstrapConfig returns a copy of the supplied configuration with
// secret attributes removed. If the resulting config is not suitable
// for bootstrapping an environment, an error is returned.
func BootstrapConfig(cfg *config.Config) (*config.Config, error) {
	p, err := Provider(cfg.Type())
	if err != nil {
		return nil, err
	}
	secrets, err := p.SecretAttrs(cfg)
	if err != nil {
		return nil, err
	}
	m := cfg.AllAttrs()
	for k := range secrets {
		delete(m, k)
	}

	// We never want to push admin-secret or the root CA private key to the cloud.
	delete(m, "admin-secret")
	m["ca-private-key"] = ""
	if cfg, err = config.New(m); err != nil {
		return nil, err
	}
	if _, ok := cfg.AgentVersion(); !ok {
		return nil, fmt.Errorf("environment configuration has no agent-version")
	}
	return cfg, nil
}