client.go

/*
Copyright (c) 2014-2018 VMware, Inc. All Rights Reserved.

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 flags

import (
	"context"
	"crypto/sha1"
	"crypto/tls"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"os/signal"
	"path/filepath"
	"strings"
	"syscall"
	"time"

	"github.com/vmware/govmomi/session"
	"github.com/vmware/govmomi/sts"
	"github.com/vmware/govmomi/vapi/rest"
	"github.com/vmware/govmomi/vim25"
	"github.com/vmware/govmomi/vim25/soap"
	"github.com/vmware/govmomi/vim25/types"
)

const (
	envURL           = "GOVC_URL"
	envUsername      = "GOVC_USERNAME"
	envPassword      = "GOVC_PASSWORD"
	envCertificate   = "GOVC_CERTIFICATE"
	envPrivateKey    = "GOVC_PRIVATE_KEY"
	envInsecure      = "GOVC_INSECURE"
	envPersist       = "GOVC_PERSIST_SESSION"
	envMinAPIVersion = "GOVC_MIN_API_VERSION"
	envVimNamespace  = "GOVC_VIM_NAMESPACE"
	envVimVersion    = "GOVC_VIM_VERSION"
	envTLSCaCerts    = "GOVC_TLS_CA_CERTS"
	envTLSKnownHosts = "GOVC_TLS_KNOWN_HOSTS"

	defaultMinVimVersion = "5.5"
)

const cDescr = "ESX or vCenter URL"

type ClientFlag struct {
	common

	*DebugFlag

	url           *url.URL
	username      string
	password      string
	cert          string
	key           string
	insecure      bool
	persist       bool
	minAPIVersion string
	vimNamespace  string
	vimVersion    string
	tlsCaCerts    string
	tlsKnownHosts string
	client        *vim25.Client

	Login func(context.Context, *vim25.Client) error
}

var (
	home          = os.Getenv("GOVMOMI_HOME")
	clientFlagKey = flagKey("client")
)

func init() {
	if home == "" {
		home = filepath.Join(os.Getenv("HOME"), ".govmomi")
	}
}

func NewClientFlag(ctx context.Context) (*ClientFlag, context.Context) {
	if v := ctx.Value(clientFlagKey); v != nil {
		return v.(*ClientFlag), ctx
	}

	v := &ClientFlag{}
	v.Login = v.login
	v.DebugFlag, ctx = NewDebugFlag(ctx)
	ctx = context.WithValue(ctx, clientFlagKey, v)
	return v, ctx
}

func (flag *ClientFlag) URLWithoutPassword() *url.URL {
	if flag.url == nil {
		return nil
	}

	withoutCredentials := *flag.url
	withoutCredentials.User = url.User(flag.url.User.Username())
	return &withoutCredentials
}

func (flag *ClientFlag) Userinfo() *url.Userinfo {
	return flag.url.User
}

func (flag *ClientFlag) IsSecure() bool {
	return !flag.insecure
}

func (flag *ClientFlag) String() string {
	url := flag.URLWithoutPassword()
	if url == nil {
		return ""
	}

	return url.String()
}

func (flag *ClientFlag) Set(s string) error {
	var err error

	flag.url, err = soap.ParseURL(s)

	return err
}

func (flag *ClientFlag) Register(ctx context.Context, f *flag.FlagSet) {
	flag.RegisterOnce(func() {
		flag.DebugFlag.Register(ctx, f)

		{
			flag.Set(os.Getenv(envURL))
			usage := fmt.Sprintf("%s [%s]", cDescr, envURL)
			f.Var(flag, "u", usage)
		}

		{
			flag.username = os.Getenv(envUsername)
			flag.password = os.Getenv(envPassword)
		}

		{
			value := os.Getenv(envCertificate)
			usage := fmt.Sprintf("Certificate [%s]", envCertificate)
			f.StringVar(&flag.cert, "cert", value, usage)
		}

		{
			value := os.Getenv(envPrivateKey)
			usage := fmt.Sprintf("Private key [%s]", envPrivateKey)
			f.StringVar(&flag.key, "key", value, usage)
		}

		{
			insecure := false
			switch env := strings.ToLower(os.Getenv(envInsecure)); env {
			case "1", "true":
				insecure = true
			}

			usage := fmt.Sprintf("Skip verification of server certificate [%s]", envInsecure)
			f.BoolVar(&flag.insecure, "k", insecure, usage)
		}

		{
			persist := true
			switch env := strings.ToLower(os.Getenv(envPersist)); env {
			case "0", "false":
				persist = false
			}

			usage := fmt.Sprintf("Persist session to disk [%s]", envPersist)
			f.BoolVar(&flag.persist, "persist-session", persist, usage)
		}

		{
			env := os.Getenv(envMinAPIVersion)
			if env == "" {
				env = defaultMinVimVersion
			}

			flag.minAPIVersion = env
		}

		{
			value := os.Getenv(envVimNamespace)
			if value == "" {
				value = vim25.Namespace
			}
			usage := fmt.Sprintf("Vim namespace [%s]", envVimNamespace)
			f.StringVar(&flag.vimNamespace, "vim-namespace", value, usage)
		}

		{
			value := os.Getenv(envVimVersion)
			if value == "" {
				value = vim25.Version
			}
			usage := fmt.Sprintf("Vim version [%s]", envVimVersion)
			f.StringVar(&flag.vimVersion, "vim-version", value, usage)
		}

		{
			value := os.Getenv(envTLSCaCerts)
			usage := fmt.Sprintf("TLS CA certificates file [%s]", envTLSCaCerts)
			f.StringVar(&flag.tlsCaCerts, "tls-ca-certs", value, usage)
		}

		{
			value := os.Getenv(envTLSKnownHosts)
			usage := fmt.Sprintf("TLS known hosts file [%s]", envTLSKnownHosts)
			f.StringVar(&flag.tlsKnownHosts, "tls-known-hosts", value, usage)
		}
	})
}

func (flag *ClientFlag) Process(ctx context.Context) error {
	return flag.ProcessOnce(func() error {
		if err := flag.DebugFlag.Process(ctx); err != nil {
			return err
		}

		if flag.url == nil {
			return errors.New("specify an " + cDescr)
		}

		// Override username if set
		if flag.username != "" {
			var password string
			var ok bool

			if flag.url.User != nil {
				password, ok = flag.url.User.Password()
			}

			if ok {
				flag.url.User = url.UserPassword(flag.username, password)
			} else {
				flag.url.User = url.User(flag.username)
			}
		}

		// Override password if set
		if flag.password != "" {
			var username string

			if flag.url.User != nil {
				username = flag.url.User.Username()
			}

			flag.url.User = url.UserPassword(username, flag.password)
		}

		return nil
	})
}

// configure TLS and retry settings before making any connections
func (flag *ClientFlag) configure(sc *soap.Client) (soap.RoundTripper, error) {
	if flag.cert != "" {
		cert, err := tls.LoadX509KeyPair(flag.cert, flag.key)
		if err != nil {
			return nil, err
		}

		sc.SetCertificate(cert)
	}

	// Set namespace and version
	sc.Namespace = "urn:" + flag.vimNamespace
	sc.Version = flag.vimVersion

	sc.UserAgent = fmt.Sprintf("govc/%s", Version)

	if err := flag.SetRootCAs(sc); err != nil {
		return nil, err
	}

	if err := sc.LoadThumbprints(flag.tlsKnownHosts); err != nil {
		return nil, err
	}

	if t, ok := sc.Transport.(*http.Transport); ok {
		var err error

		value := os.Getenv("GOVC_TLS_HANDSHAKE_TIMEOUT")
		if value != "" {
			t.TLSHandshakeTimeout, err = time.ParseDuration(value)
			if err != nil {
				return nil, err
			}
		}
	}

	// Retry twice when a temporary I/O error occurs.
	// This means a maximum of 3 attempts.
	return vim25.Retry(sc, vim25.TemporaryNetworkError(3)), nil
}

func (flag *ClientFlag) sessionFile() string {
	url := flag.URLWithoutPassword()

	// Key session file off of full URI and insecure setting.
	// Hash key to get a predictable, canonical format.
	key := fmt.Sprintf("%s#insecure=%t", url.String(), flag.insecure)
	name := fmt.Sprintf("%040x", sha1.Sum([]byte(key)))
	return filepath.Join(home, "sessions", name)
}

func (flag *ClientFlag) saveClient(c *vim25.Client) error {
	if !flag.persist {
		return nil
	}

	p := flag.sessionFile()
	err := os.MkdirAll(filepath.Dir(p), 0700)
	if err != nil {
		return err
	}

	f, err := os.OpenFile(p, os.O_CREATE|os.O_WRONLY, 0600)
	if err != nil {
		return err
	}
	defer f.Close()

	err = json.NewEncoder(f).Encode(c)
	if err != nil {
		return err
	}

	return nil
}

func (flag *ClientFlag) restoreClient(c *vim25.Client) (bool, error) {
	if !flag.persist {
		return false, nil
	}

	f, err := os.Open(flag.sessionFile())
	if err != nil {
		if os.IsNotExist(err) {
			return false, nil
		}

		return false, err
	}

	defer f.Close()

	dec := json.NewDecoder(f)
	err = dec.Decode(c)
	if err != nil {
		return false, err
	}

	return true, nil
}

func (flag *ClientFlag) loadClient() (*vim25.Client, error) {
	c := new(vim25.Client)
	ok, err := flag.restoreClient(c)
	if err != nil {
		return nil, err
	}

	if !ok || !c.Valid() {
		return nil, nil
	}

	c.RoundTripper, err = flag.configure(c.Client)
	if err != nil {
		return nil, err
	}

	m := session.NewManager(c)
	u, err := m.UserSession(context.TODO())
	if err != nil {
		if soap.IsSoapFault(err) {
			fault := soap.ToSoapFault(err).VimFault()
			// If the PropertyCollector is not found, the saved session for this URL is not valid
			if _, ok := fault.(types.ManagedObjectNotFound); ok {
				return nil, nil
			}
		}

		return nil, err
	}

	// If the session is nil, the client is not authenticated
	if u == nil {
		return nil, nil
	}

	return c, nil
}

func (flag *ClientFlag) SetRootCAs(c *soap.Client) error {
	if flag.tlsCaCerts != "" {
		return c.SetRootCAs(flag.tlsCaCerts)
	}
	return nil
}

func (flag *ClientFlag) login(ctx context.Context, c *vim25.Client) error {
	m := session.NewManager(c)
	u := flag.url.User
	name := u.Username()

	if name == "" && !c.IsVC() {
		// If no username is provided, try to acquire a local ticket.
		// When invoked remotely, ESX returns an InvalidRequestFault.
		// So, rather than return an error here, fallthrough to Login() with the original User to
		// to avoid what would be a confusing error message.
		luser, lerr := flag.localTicket(ctx, m)
		if lerr == nil {
			// We are running directly on an ESX or Workstation host and can use the ticket with Login()
			u = luser
			name = u.Username()
		}
	}
	if name == "" {
		// Skip auto-login if we don't have a username
		flag.persist = true // Not persisting, but this avoids the call to Logout()
		return nil          // Avoid SaveSession for non-authenticated session
	}

	return m.Login(ctx, u)
}

func (flag *ClientFlag) newClient() (*vim25.Client, error) {
	ctx := context.TODO()
	sc := soap.NewClient(flag.url, flag.insecure)

	rt, err := flag.configure(sc)
	if err != nil {
		return nil, err
	}

	c, err := vim25.NewClient(ctx, rt)
	if err != nil {
		return nil, err
	}

	// Set client, since we didn't pass it in the constructor
	c.Client = sc

	if err := flag.Login(ctx, c); err != nil {
		return nil, err
	}

	return c, flag.saveClient(c)
}

func (flag *ClientFlag) localTicket(ctx context.Context, m *session.Manager) (*url.Userinfo, error) {
	ticket, err := m.AcquireLocalTicket(ctx, os.Getenv("USER"))
	if err != nil {
		return nil, err
	}

	password, err := ioutil.ReadFile(ticket.PasswordFilePath)
	if err != nil {
		return nil, err
	}

	return url.UserPassword(ticket.UserName, string(password)), nil
}

func isDevelopmentVersion(apiVersion string) bool {
	// Skip version check for development builds which can be in the form of "r4A70F" or "6.5.x"
	return strings.Count(apiVersion, ".") == 0 || strings.HasSuffix(apiVersion, ".x")
}

// apiVersionValid returns whether or not the API version supported by the
// server the client is connected to is not recent enough.
func apiVersionValid(c *vim25.Client, minVersionString string) error {
	if minVersionString == "-" {
		// Disable version check
		return nil
	}

	apiVersion := c.ServiceContent.About.ApiVersion
	if isDevelopmentVersion(apiVersion) {
		return nil
	}

	realVersion, err := ParseVersion(apiVersion)
	if err != nil {
		return fmt.Errorf("Error parsing API version %q: %s", apiVersion, err)
	}

	minVersion, err := ParseVersion(minVersionString)
	if err != nil {
		return fmt.Errorf("Error parsing %s=%q: %s", envMinAPIVersion, minVersionString, err)
	}

	if !minVersion.Lte(realVersion) {
		err = fmt.Errorf("Require API version %q, connected to API version %q (set %s to override)",
			minVersionString,
			c.ServiceContent.About.ApiVersion,
			envMinAPIVersion)
		return err
	}

	return nil
}

func (flag *ClientFlag) Client() (*vim25.Client, error) {
	if flag.client != nil {
		return flag.client, nil
	}

	c, err := flag.loadClient()
	if err != nil {
		return nil, err
	}

	// loadClient returns nil if it was unable to load a session from disk
	if c == nil {
		c, err = flag.newClient()
		if err != nil {
			return nil, err
		}
	}

	// Check that the endpoint has the right API version
	err = apiVersionValid(c, flag.minAPIVersion)
	if err != nil {
		return nil, err
	}

	flag.client = c
	return flag.client, nil
}

func (flag *ClientFlag) Logout(ctx context.Context) error {
	if flag.persist || flag.client == nil {
		return nil
	}

	m := session.NewManager(flag.client)

	return m.Logout(ctx)
}

func (flag *ClientFlag) WithRestClient(ctx context.Context, f func(*rest.Client) error) error {
	vc, err := flag.Client()
	if err != nil {
		return err
	}

	c := rest.NewClient(vc)
	if err != nil {
		return err
	}

	// TODO: rest.Client session cookie should be persisted as the soap.Client session cookie is.
	if vc.Certificate() == nil {
		if err = c.Login(ctx, flag.Userinfo()); err != nil {
			return err
		}
	} else {
		// TODO: session.login should support rest.Client SSO login to avoid this env var (depends on the TODO above)
		token := os.Getenv("GOVC_LOGIN_TOKEN")
		if token == "" {
			return errors.New("GOVC_LOGIN_TOKEN must be set for rest.Client SSO login")
		}
		signer := &sts.Signer{
			Certificate: c.Certificate(),
			Token:       token,
		}

		if err = c.LoginByToken(c.WithSigner(ctx, signer)); err != nil {
			return err
		}
	}

	defer c.Logout(ctx)

	return f(c)
}

// Environ returns the govc environment variables for this connection
func (flag *ClientFlag) Environ(extra bool) []string {
	var env []string
	add := func(k, v string) {
		env = append(env, fmt.Sprintf("%s=%s", k, v))
	}

	u := *flag.url
	if u.User != nil {
		add(envUsername, u.User.Username())

		if p, ok := u.User.Password(); ok {
			add(envPassword, p)
		}

		u.User = nil
	}

	if u.Path == vim25.Path {
		u.Path = ""
	}
	u.Fragment = ""
	u.RawQuery = ""

	val := u.String()
	prefix := "https://"
	if strings.HasPrefix(val, prefix) {
		val = val[len(prefix):]
	}
	add(envURL, val)

	keys := []string{
		envCertificate,
		envPrivateKey,
		envInsecure,
		envPersist,
		envMinAPIVersion,
		envVimNamespace,
		envVimVersion,
	}

	for _, k := range keys {
		if v := os.Getenv(k); v != "" {
			add(k, v)
		}
	}

	if extra {
		add("GOVC_URL_SCHEME", flag.url.Scheme)

		v := strings.SplitN(u.Host, ":", 2)
		add("GOVC_URL_HOST", v[0])
		if len(v) == 2 {
			add("GOVC_URL_PORT", v[1])
		}

		add("GOVC_URL_PATH", flag.url.Path)

		if f := flag.url.Fragment; f != "" {
			add("GOVC_URL_FRAGMENT", f)
		}

		if q := flag.url.RawQuery; q != "" {
			add("GOVC_URL_QUERY", q)
		}
	}

	return env
}

// WithCancel calls the given function, returning when complete or canceled via SIGINT.
func (flag *ClientFlag) WithCancel(ctx context.Context, f func(context.Context) error) error {
	sig := make(chan os.Signal, 1)
	signal.Notify(sig, syscall.SIGINT)

	wctx, cancel := context.WithCancel(ctx)
	defer cancel()

	done := make(chan bool)
	var werr error

	go func() {
		defer close(done)
		werr = f(wctx)
	}()

	select {
	case <-sig:
		cancel()
		<-done // Wait for f() to complete
	case <-done:
	}

	return werr
}