Merge pull request #1456 from timstclair/cloud-api

Cherrypick #1455: Fix google cloud godeps

Godeps/Godeps.json

@@ -11,6 +11,16 @@
 			"Comment": "null-5",
 			"Rev": "'75cd24fc2f2c2a2088577d12123ddee5f54e0675'"
 		},
+		{
+			"ImportPath": "cloud.google.com/go/compute/metadata",
+			"Comment": "v0.1.0-115-g3b1ae45",
+			"Rev": "3b1ae45394a234c385be014e9a488f2bb6eef821"
+		},
+		{
+			"ImportPath": "cloud.google.com/go/internal",
+			"Comment": "v0.1.0-115-g3b1ae45",
+			"Rev": "3b1ae45394a234c385be014e9a488f2bb6eef821"
+		},
 		{
 			"ImportPath": "github.com/Microsoft/go-winio",
 			"Comment": "v0.3.2",
@@ -471,6 +481,10 @@
 			"ImportPath": "golang.org/x/net/context",
 			"Rev": "5627bad10b821d907ac4dc81fb3535ec7dd81c2b"
 		},
+		{
+			"ImportPath": "golang.org/x/net/context/ctxhttp",
+			"Rev": "5627bad10b821d907ac4dc81fb3535ec7dd81c2b"
+		},
 		{
 			"ImportPath": "golang.org/x/net/http2",
 			"Rev": "5627bad10b821d907ac4dc81fb3535ec7dd81c2b"
@@ -519,14 +533,6 @@
 			"ImportPath": "google.golang.org/api/googleapi/internal/uritemplates",
 			"Rev": "0c2979aeaa5b573e60d3ddffe5ce8dca8df309bd"
 		},
-		{
-			"ImportPath": "google.golang.org/cloud/compute/metadata",
-			"Rev": "542bfb014d8e28df6e27be847dfdc40c510dab1a"
-		},
-		{
-			"ImportPath": "google.golang.org/cloud/internal",
-			"Rev": "542bfb014d8e28df6e27be847dfdc40c510dab1a"
-		},
 		{
 			"ImportPath": "google.golang.org/grpc",
 			"Rev": "3c4302b7131d2b14bb9c8aff7aa909bc20540145"

utils/cloudinfo/gce.go

@@ -20,8 +20,8 @@ import (
 
 	info "github.com/google/cadvisor/info/v1"
 
+	"cloud.google.com/go/compute/metadata"
 	"github.com/golang/glog"
-	"google.golang.org/cloud/compute/metadata"
 )
 
 const (

vendor/cloud.google.com/go/compute/metadata/metadata.go

@@ -0,0 +1,438 @@
+// Copyright 2014 Google 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 metadata provides access to Google Compute Engine (GCE)
+// metadata and API service accounts.
+//
+// This package is a wrapper around the GCE metadata service,
+// as documented at https://developers.google.com/compute/docs/metadata.
+package metadata
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+	"golang.org/x/net/context/ctxhttp"
+
+	"cloud.google.com/go/internal"
+)
+
+const (
+	// metadataIP is the documented metadata server IP address.
+	metadataIP = "169.254.169.254"
+
+	// metadataHostEnv is the environment variable specifying the
+	// GCE metadata hostname.  If empty, the default value of
+	// metadataIP ("169.254.169.254") is used instead.
+	// This is variable name is not defined by any spec, as far as
+	// I know; it was made up for the Go package.
+	metadataHostEnv = "GCE_METADATA_HOST"
+)
+
+type cachedValue struct {
+	k    string
+	trim bool
+	mu   sync.Mutex
+	v    string
+}
+
+var (
+	projID  = &cachedValue{k: "project/project-id", trim: true}
+	projNum = &cachedValue{k: "project/numeric-project-id", trim: true}
+	instID  = &cachedValue{k: "instance/id", trim: true}
+)
+
+var (
+	metaClient = &http.Client{
+		Transport: &internal.Transport{
+			Base: &http.Transport{
+				Dial: (&net.Dialer{
+					Timeout:   2 * time.Second,
+					KeepAlive: 30 * time.Second,
+				}).Dial,
+				ResponseHeaderTimeout: 2 * time.Second,
+			},
+		},
+	}
+	subscribeClient = &http.Client{
+		Transport: &internal.Transport{
+			Base: &http.Transport{
+				Dial: (&net.Dialer{
+					Timeout:   2 * time.Second,
+					KeepAlive: 30 * time.Second,
+				}).Dial,
+			},
+		},
+	}
+)
+
+// NotDefinedError is returned when requested metadata is not defined.
+//
+// The underlying string is the suffix after "/computeMetadata/v1/".
+//
+// This error is not returned if the value is defined to be the empty
+// string.
+type NotDefinedError string
+
+func (suffix NotDefinedError) Error() string {
+	return fmt.Sprintf("metadata: GCE metadata %q not defined", string(suffix))
+}
+
+// Get returns a value from the metadata service.
+// The suffix is appended to "http://${GCE_METADATA_HOST}/computeMetadata/v1/".
+//
+// If the GCE_METADATA_HOST environment variable is not defined, a default of
+// 169.254.169.254 will be used instead.
+//
+// If the requested metadata is not defined, the returned error will
+// be of type NotDefinedError.
+func Get(suffix string) (string, error) {
+	val, _, err := getETag(metaClient, suffix)
+	return val, err
+}
+
+// getETag returns a value from the metadata service as well as the associated
+// ETag using the provided client. This func is otherwise equivalent to Get.
+func getETag(client *http.Client, suffix string) (value, etag string, err error) {
+	// Using a fixed IP makes it very difficult to spoof the metadata service in
+	// a container, which is an important use-case for local testing of cloud
+	// deployments. To enable spoofing of the metadata service, the environment
+	// variable GCE_METADATA_HOST is first inspected to decide where metadata
+	// requests shall go.
+	host := os.Getenv(metadataHostEnv)
+	if host == "" {
+		// Using 169.254.169.254 instead of "metadata" here because Go
+		// binaries built with the "netgo" tag and without cgo won't
+		// know the search suffix for "metadata" is
+		// ".google.internal", and this IP address is documented as
+		// being stable anyway.
+		host = metadataIP
+	}
+	url := "http://" + host + "/computeMetadata/v1/" + suffix
+	req, _ := http.NewRequest("GET", url, nil)
+	req.Header.Set("Metadata-Flavor", "Google")
+	res, err := client.Do(req)
+	if err != nil {
+		return "", "", err
+	}
+	defer res.Body.Close()
+	if res.StatusCode == http.StatusNotFound {
+		return "", "", NotDefinedError(suffix)
+	}
+	if res.StatusCode != 200 {
+		return "", "", fmt.Errorf("status code %d trying to fetch %s", res.StatusCode, url)
+	}
+	all, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return "", "", err
+	}
+	return string(all), res.Header.Get("Etag"), nil
+}
+
+func getTrimmed(suffix string) (s string, err error) {
+	s, err = Get(suffix)
+	s = strings.TrimSpace(s)
+	return
+}
+
+func (c *cachedValue) get() (v string, err error) {
+	defer c.mu.Unlock()
+	c.mu.Lock()
+	if c.v != "" {
+		return c.v, nil
+	}
+	if c.trim {
+		v, err = getTrimmed(c.k)
+	} else {
+		v, err = Get(c.k)
+	}
+	if err == nil {
+		c.v = v
+	}
+	return
+}
+
+var (
+	onGCEOnce sync.Once
+	onGCE     bool
+)
+
+// OnGCE reports whether this process is running on Google Compute Engine.
+func OnGCE() bool {
+	onGCEOnce.Do(initOnGCE)
+	return onGCE
+}
+
+func initOnGCE() {
+	onGCE = testOnGCE()
+}
+
+func testOnGCE() bool {
+	// The user explicitly said they're on GCE, so trust them.
+	if os.Getenv(metadataHostEnv) != "" {
+		return true
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	resc := make(chan bool, 2)
+
+	// Try two strategies in parallel.
+	// See https://github.com/GoogleCloudPlatform/google-cloud-go/issues/194
+	go func() {
+		res, err := ctxhttp.Get(ctx, metaClient, "http://"+metadataIP)
+		if err != nil {
+			resc <- false
+			return
+		}
+		defer res.Body.Close()
+		resc <- res.Header.Get("Metadata-Flavor") == "Google"
+	}()
+
+	go func() {
+		addrs, err := net.LookupHost("metadata.google.internal")
+		if err != nil || len(addrs) == 0 {
+			resc <- false
+			return
+		}
+		resc <- strsContains(addrs, metadataIP)
+	}()
+
+	tryHarder := systemInfoSuggestsGCE()
+	if tryHarder {
+		res := <-resc
+		if res {
+			// The first strategy succeeded, so let's use it.
+			return true
+		}
+		// Wait for either the DNS or metadata server probe to
+		// contradict the other one and say we are running on
+		// GCE. Give it a lot of time to do so, since the system
+		// info already suggests we're running on a GCE BIOS.
+		timer := time.NewTimer(5 * time.Second)
+		defer timer.Stop()
+		select {
+		case res = <-resc:
+			return res
+		case <-timer.C:
+			// Too slow. Who knows what this system is.
+			return false
+		}
+	}
+
+	// There's no hint from the system info that we're running on
+	// GCE, so use the first probe's result as truth, whether it's
+	// true or false. The goal here is to optimize for speed for
+	// users who are NOT running on GCE. We can't assume that
+	// either a DNS lookup or an HTTP request to a blackholed IP
+	// address is fast. Worst case this should return when the
+	// metaClient's Transport.ResponseHeaderTimeout or
+	// Transport.Dial.Timeout fires (in two seconds).
+	return <-resc
+}
+
+// systemInfoSuggestsGCE reports whether the local system (without
+// doing network requests) suggests that we're running on GCE. If this
+// returns true, testOnGCE tries a bit harder to reach its metadata
+// server.
+func systemInfoSuggestsGCE() bool {
+	if runtime.GOOS != "linux" {
+		// We don't have any non-Linux clues available, at least yet.
+		return false
+	}
+	slurp, _ := ioutil.ReadFile("/sys/class/dmi/id/product_name")
+	name := strings.TrimSpace(string(slurp))
+	return name == "Google" || name == "Google Compute Engine"
+}
+
+// Subscribe subscribes to a value from the metadata service.
+// The suffix is appended to "http://${GCE_METADATA_HOST}/computeMetadata/v1/".
+// The suffix may contain query parameters.
+//
+// Subscribe calls fn with the latest metadata value indicated by the provided
+// suffix. If the metadata value is deleted, fn is called with the empty string
+// and ok false. Subscribe blocks until fn returns a non-nil error or the value
+// is deleted. Subscribe returns the error value returned from the last call to
+// fn, which may be nil when ok == false.
+func Subscribe(suffix string, fn func(v string, ok bool) error) error {
+	const failedSubscribeSleep = time.Second * 5
+
+	// First check to see if the metadata value exists at all.
+	val, lastETag, err := getETag(subscribeClient, suffix)
+	if err != nil {
+		return err
+	}
+
+	if err := fn(val, true); err != nil {
+		return err
+	}
+
+	ok := true
+	if strings.ContainsRune(suffix, '?') {
+		suffix += "&wait_for_change=true&last_etag="
+	} else {
+		suffix += "?wait_for_change=true&last_etag="
+	}
+	for {
+		val, etag, err := getETag(subscribeClient, suffix+url.QueryEscape(lastETag))
+		if err != nil {
+			if _, deleted := err.(NotDefinedError); !deleted {
+				time.Sleep(failedSubscribeSleep)
+				continue // Retry on other errors.
+			}
+			ok = false
+		}
+		lastETag = etag
+
+		if err := fn(val, ok); err != nil || !ok {
+			return err
+		}
+	}
+}
+
+// ProjectID returns the current instance's project ID string.
+func ProjectID() (string, error) { return projID.get() }
+
+// NumericProjectID returns the current instance's numeric project ID.
+func NumericProjectID() (string, error) { return projNum.get() }
+
+// InternalIP returns the instance's primary internal IP address.
+func InternalIP() (string, error) {
+	return getTrimmed("instance/network-interfaces/0/ip")
+}
+
+// ExternalIP returns the instance's primary external (public) IP address.
+func ExternalIP() (string, error) {
+	return getTrimmed("instance/network-interfaces/0/access-configs/0/external-ip")
+}
+
+// Hostname returns the instance's hostname. This will be of the form
+// "<instanceID>.c.<projID>.internal".
+func Hostname() (string, error) {
+	return getTrimmed("instance/hostname")
+}
+
+// InstanceTags returns the list of user-defined instance tags,
+// assigned when initially creating a GCE instance.
+func InstanceTags() ([]string, error) {
+	var s []string
+	j, err := Get("instance/tags")
+	if err != nil {
+		return nil, err
+	}
+	if err := json.NewDecoder(strings.NewReader(j)).Decode(&s); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+// InstanceID returns the current VM's numeric instance ID.
+func InstanceID() (string, error) {
+	return instID.get()
+}
+
+// InstanceName returns the current VM's instance ID string.
+func InstanceName() (string, error) {
+	host, err := Hostname()
+	if err != nil {
+		return "", err
+	}
+	return strings.Split(host, ".")[0], nil
+}
+
+// Zone returns the current VM's zone, such as "us-central1-b".
+func Zone() (string, error) {
+	zone, err := getTrimmed("instance/zone")
+	// zone is of the form "projects/<projNum>/zones/<zoneName>".
+	if err != nil {
+		return "", err
+	}
+	return zone[strings.LastIndex(zone, "/")+1:], nil
+}
+
+// InstanceAttributes returns the list of user-defined attributes,
+// assigned when initially creating a GCE VM instance. The value of an
+// attribute can be obtained with InstanceAttributeValue.
+func InstanceAttributes() ([]string, error) { return lines("instance/attributes/") }
+
+// ProjectAttributes returns the list of user-defined attributes
+// applying to the project as a whole, not just this VM.  The value of
+// an attribute can be obtained with ProjectAttributeValue.
+func ProjectAttributes() ([]string, error) { return lines("project/attributes/") }
+
+func lines(suffix string) ([]string, error) {
+	j, err := Get(suffix)
+	if err != nil {
+		return nil, err
+	}
+	s := strings.Split(strings.TrimSpace(j), "\n")
+	for i := range s {
+		s[i] = strings.TrimSpace(s[i])
+	}
+	return s, nil
+}
+
+// InstanceAttributeValue returns the value of the provided VM
+// instance attribute.
+//
+// If the requested attribute is not defined, the returned error will
+// be of type NotDefinedError.
+//
+// InstanceAttributeValue may return ("", nil) if the attribute was
+// defined to be the empty string.
+func InstanceAttributeValue(attr string) (string, error) {
+	return Get("instance/attributes/" + attr)
+}
+
+// ProjectAttributeValue returns the value of the provided
+// project attribute.
+//
+// If the requested attribute is not defined, the returned error will
+// be of type NotDefinedError.
+//
+// ProjectAttributeValue may return ("", nil) if the attribute was
+// defined to be the empty string.
+func ProjectAttributeValue(attr string) (string, error) {
+	return Get("project/attributes/" + attr)
+}
+
+// Scopes returns the service account scopes for the given account.
+// The account may be empty or the string "default" to use the instance's
+// main account.
+func Scopes(serviceAccount string) ([]string, error) {
+	if serviceAccount == "" {
+		serviceAccount = "default"
+	}
+	return lines("instance/service-accounts/" + serviceAccount + "/scopes")
+}
+
+func strsContains(ss []string, s string) bool {
+	for _, v := range ss {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}

vendor/cloud.google.com/go/internal/cloud.go

@@ -24,24 +24,26 @@ import (
 
 const userAgent = "gcloud-golang/0.1"
 
-// UATransport is an http.RoundTripper that appends
+// Transport is an http.RoundTripper that appends Google Cloud client's
-// Google Cloud client's user-agent to the original
+// user-agent to the original request's user-agent header.
-// request's user-agent header.
+type Transport struct {
-type UATransport struct {
+	// TODO(bradfitz): delete internal.Transport. It's too wrappy for what it does.
-	// Base represents the actual http.RoundTripper
+	// Do User-Agent some other way.
-	// the requests will be delegated to.
+
+	// Base is the actual http.RoundTripper
+	// requests will use. It must not be nil.
 	Base http.RoundTripper
 }
 
 // RoundTrip appends a user-agent to the existing user-agent
 // header and delegates the request to the base http.RoundTripper.
-func (t *UATransport) RoundTrip(req *http.Request) (*http.Response, error) {
+func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
 	req = cloneRequest(req)
 	ua := req.Header.Get("User-Agent")
 	if ua == "" {
 		ua = userAgent
 	} else {
-		ua = fmt.Sprintf("%s;%s", ua, userAgent)
+		ua = fmt.Sprintf("%s %s", ua, userAgent)
 	}
 	req.Header.Set("User-Agent", ua)
 	return t.Base.RoundTrip(req)

vendor/golang.org/x/net/context/ctxhttp/cancelreq.go

@@ -0,0 +1,18 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.5
+
+package ctxhttp
+
+import "net/http"
+
+func canceler(client *http.Client, req *http.Request) func() {
+	ch := make(chan struct{})
+	req.Cancel = ch
+
+	return func() {
+		close(ch)
+	}
+}

vendor/golang.org/x/net/context/ctxhttp/cancelreq_go14.go

@@ -0,0 +1,23 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.5
+
+package ctxhttp
+
+import "net/http"
+
+type requestCanceler interface {
+	CancelRequest(*http.Request)
+}
+
+func canceler(client *http.Client, req *http.Request) func() {
+	rc, ok := client.Transport.(requestCanceler)
+	if !ok {
+		return func() {}
+	}
+	return func() {
+		rc.CancelRequest(req)
+	}
+}

vendor/golang.org/x/net/context/ctxhttp/ctxhttp.go

@@ -0,0 +1,79 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package ctxhttp provides helper functions for performing context-aware HTTP requests.
+package ctxhttp
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"golang.org/x/net/context"
+)
+
+// Do sends an HTTP request with the provided http.Client and returns an HTTP response.
+// If the client is nil, http.DefaultClient is used.
+// If the context is canceled or times out, ctx.Err() will be returned.
+func Do(ctx context.Context, client *http.Client, req *http.Request) (*http.Response, error) {
+	if client == nil {
+		client = http.DefaultClient
+	}
+
+	// Request cancelation changed in Go 1.5, see cancelreq.go and cancelreq_go14.go.
+	cancel := canceler(client, req)
+
+	type responseAndError struct {
+		resp *http.Response
+		err  error
+	}
+	result := make(chan responseAndError, 1)
+
+	go func() {
+		resp, err := client.Do(req)
+		result <- responseAndError{resp, err}
+	}()
+
+	select {
+	case <-ctx.Done():
+		cancel()
+		return nil, ctx.Err()
+	case r := <-result:
+		return r.resp, r.err
+	}
+}
+
+// Get issues a GET request via the Do function.
+func Get(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return Do(ctx, client, req)
+}
+
+// Head issues a HEAD request via the Do function.
+func Head(ctx context.Context, client *http.Client, url string) (*http.Response, error) {
+	req, err := http.NewRequest("HEAD", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return Do(ctx, client, req)
+}
+
+// Post issues a POST request via the Do function.
+func Post(ctx context.Context, client *http.Client, url string, bodyType string, body io.Reader) (*http.Response, error) {
+	req, err := http.NewRequest("POST", url, body)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", bodyType)
+	return Do(ctx, client, req)
+}
+
+// PostForm issues a POST request via the Do function.
+func PostForm(ctx context.Context, client *http.Client, url string, data url.Values) (*http.Response, error) {
+	return Post(ctx, client, url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
+}

vendor/google.golang.org/cloud/compute/metadata/metadata.go

@@ -1,221 +0,0 @@
-// Copyright 2014 Google 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 metadata provides access to Google Compute Engine (GCE)
-// metadata and API service accounts.
-//
-// This package is a wrapper around the GCE metadata service,
-// as documented at https://developers.google.com/compute/docs/metadata.
-package metadata
-
-import (
-	"encoding/json"
-	"fmt"
-	"io/ioutil"
-	"net"
-	"net/http"
-	"strings"
-	"sync"
-	"time"
-
-	"google.golang.org/cloud/internal"
-)
-
-type cachedValue struct {
-	k    string
-	trim bool
-	mu   sync.Mutex
-	v    string
-}
-
-var (
-	projID  = &cachedValue{k: "project/project-id", trim: true}
-	projNum = &cachedValue{k: "project/numeric-project-id", trim: true}
-	instID  = &cachedValue{k: "instance/id", trim: true}
-)
-
-var metaClient = &http.Client{
-	Transport: &internal.UATransport{
-		Base: &http.Transport{
-			Dial: (&net.Dialer{
-				Timeout:   750 * time.Millisecond,
-				KeepAlive: 30 * time.Second,
-			}).Dial,
-			ResponseHeaderTimeout: 750 * time.Millisecond,
-		},
-	},
-}
-
-// Get returns a value from the metadata service.
-// The suffix is appended to "http://metadata/computeMetadata/v1/".
-func Get(suffix string) (string, error) {
-	// Using 169.254.169.254 instead of "metadata" here because Go
-	// binaries built with the "netgo" tag and without cgo won't
-	// know the search suffix for "metadata" is
-	// ".google.internal", and this IP address is documented as
-	// being stable anyway.
-	url := "http://169.254.169.254/computeMetadata/v1/" + suffix
-	req, _ := http.NewRequest("GET", url, nil)
-	req.Header.Set("Metadata-Flavor", "Google")
-	res, err := metaClient.Do(req)
-	if err != nil {
-		return "", err
-	}
-	defer res.Body.Close()
-	if res.StatusCode != 200 {
-		return "", fmt.Errorf("status code %d trying to fetch %s", res.StatusCode, url)
-	}
-	all, err := ioutil.ReadAll(res.Body)
-	if err != nil {
-		return "", err
-	}
-	return string(all), nil
-}
-
-func getTrimmed(suffix string) (s string, err error) {
-	s, err = Get(suffix)
-	s = strings.TrimSpace(s)
-	return
-}
-
-func (c *cachedValue) get() (v string, err error) {
-	defer c.mu.Unlock()
-	c.mu.Lock()
-	if c.v != "" {
-		return c.v, nil
-	}
-	if c.trim {
-		v, err = getTrimmed(c.k)
-	} else {
-		v, err = Get(c.k)
-	}
-	if err == nil {
-		c.v = v
-	}
-	return
-}
-
-var onGCE struct {
-	sync.Mutex
-	set bool
-	v   bool
-}
-
-// OnGCE reports whether this process is running on Google Compute Engine.
-func OnGCE() bool {
-	defer onGCE.Unlock()
-	onGCE.Lock()
-	if onGCE.set {
-		return onGCE.v
-	}
-	onGCE.set = true
-
-	// We use the DNS name of the metadata service here instead of the IP address
-	// because we expect that to fail faster in the not-on-GCE case.
-	res, err := metaClient.Get("http://metadata.google.internal")
-	if err != nil {
-		return false
-	}
-	onGCE.v = res.Header.Get("Metadata-Flavor") == "Google"
-	return onGCE.v
-}
-
-// ProjectID returns the current instance's project ID string.
-func ProjectID() (string, error) { return projID.get() }
-
-// NumericProjectID returns the current instance's numeric project ID.
-func NumericProjectID() (string, error) { return projNum.get() }
-
-// InternalIP returns the instance's primary internal IP address.
-func InternalIP() (string, error) {
-	return getTrimmed("instance/network-interfaces/0/ip")
-}
-
-// ExternalIP returns the instance's primary external (public) IP address.
-func ExternalIP() (string, error) {
-	return getTrimmed("instance/network-interfaces/0/access-configs/0/external-ip")
-}
-
-// Hostname returns the instance's hostname. This will probably be of
-// the form "INSTANCENAME.c.PROJECT.internal" but that isn't
-// guaranteed.
-//
-// TODO: what is this defined to be? Docs say "The host name of the
-// instance."
-func Hostname() (string, error) {
-	return getTrimmed("network-interfaces/0/ip")
-}
-
-// InstanceTags returns the list of user-defined instance tags,
-// assigned when initially creating a GCE instance.
-func InstanceTags() ([]string, error) {
-	var s []string
-	j, err := Get("instance/tags")
-	if err != nil {
-		return nil, err
-	}
-	if err := json.NewDecoder(strings.NewReader(j)).Decode(&s); err != nil {
-		return nil, err
-	}
-	return s, nil
-}
-
-// InstanceID returns the current VM's numeric instance ID.
-func InstanceID() (string, error) {
-	return instID.get()
-}
-
-// InstanceAttributes returns the list of user-defined attributes,
-// assigned when initially creating a GCE VM instance. The value of an
-// attribute can be obtained with InstanceAttributeValue.
-func InstanceAttributes() ([]string, error) { return lines("instance/attributes/") }
-
-// ProjectAttributes returns the list of user-defined attributes
-// applying to the project as a whole, not just this VM.  The value of
-// an attribute can be obtained with ProjectAttributeValue.
-func ProjectAttributes() ([]string, error) { return lines("project/attributes/") }
-
-func lines(suffix string) ([]string, error) {
-	j, err := Get(suffix)
-	if err != nil {
-		return nil, err
-	}
-	s := strings.Split(strings.TrimSpace(j), "\n")
-	for i := range s {
-		s[i] = strings.TrimSpace(s[i])
-	}
-	return s, nil
-}
-
-// InstanceAttributeValue returns the value of the provided VM
-// instance attribute.
-func InstanceAttributeValue(attr string) (string, error) {
-	return Get("instance/attributes/" + attr)
-}
-
-// ProjectAttributeValue returns the value of the provided
-// project attribute.
-func ProjectAttributeValue(attr string) (string, error) {
-	return Get("project/attributes/" + attr)
-}
-
-// Scopes returns the service account scopes for the given account.
-// The account may be empty or the string "default" to use the instance's
-// main account.
-func Scopes(serviceAccount string) ([]string, error) {
-	if serviceAccount == "" {
-		serviceAccount = "default"
-	}
-	return lines("instance/service-accounts/" + serviceAccount + "/scopes")
-}