Adding GCE metadata lib

Godeps/Godeps.json

@@ -29,6 +29,10 @@
 			"Comment": "release-101",
 			"Rev": "e1c259484b495133836706f46319f5897f1e9bf6"
 		},
+		{
+			"ImportPath": "github.com/GoogleCloudPlatform/gcloud-golang/compute/metadata",
+			"Rev": "542bfb014d8e28df6e27be847dfdc40c510dab1a"
+		},
 		{
 			"ImportPath": "github.com/SeanDolphin/bqschema",
 			"Rev": "a713d26df274e999ec10e9bbc7e73a1c4791053c"
@@ -105,6 +109,10 @@
 		{
 			"ImportPath": "github.com/stretchr/testify/require",
 			"Rev": "8ce79b9f0b77745113f82c17d0756771456ccbd3"
+		},
+		{
+			"ImportPath": "google.golang.org/cloud/internal",
+			"Rev": "542bfb014d8e28df6e27be847dfdc40c510dab1a"
 		}
 	]
 }

Godeps/_workspace/src/github.com/GoogleCloudPlatform/gcloud-golang/compute/metadata/metadata.go

@@ -0,0 +1,221 @@
+// 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")
+}

Godeps/_workspace/src/google.golang.org/cloud/internal/cloud.go

@@ -0,0 +1,62 @@
+// 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 internal provides support for the cloud packages.
+//
+// Users should not import this package directly.
+package internal
+
+import (
+	"fmt"
+	"net/http"
+)
+
+const userAgent = "gcloud-golang/0.1"
+
+// UATransport is an http.RoundTripper that appends
+// Google Cloud client's user-agent to the original
+// request's user-agent header.
+type UATransport struct {
+	// Base represents the actual http.RoundTripper
+	// the requests will be delegated to.
+	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) {
+	req = cloneRequest(req)
+	ua := req.Header.Get("User-Agent")
+	if ua == "" {
+		ua = userAgent
+	} else {
+		ua = fmt.Sprintf("%s;%s", ua, userAgent)
+	}
+	req.Header.Set("User-Agent", ua)
+	return t.Base.RoundTrip(req)
+}
+
+// cloneRequest returns a clone of the provided *http.Request.
+// The clone is a shallow copy of the struct and its Header map.
+func cloneRequest(r *http.Request) *http.Request {
+	// shallow copy of the struct
+	r2 := new(http.Request)
+	*r2 = *r
+	// deep copy of the Header
+	r2.Header = make(http.Header)
+	for k, s := range r.Header {
+		r2.Header[k] = s
+	}
+	return r2
+}