diff options
Diffstat (limited to 'src/kube2msb/vendor/google.golang.org/cloud/compute/metadata')
-rw-r--r-- | src/kube2msb/vendor/google.golang.org/cloud/compute/metadata/metadata.go | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/src/kube2msb/vendor/google.golang.org/cloud/compute/metadata/metadata.go b/src/kube2msb/vendor/google.golang.org/cloud/compute/metadata/metadata.go new file mode 100644 index 0000000..0a70959 --- /dev/null +++ b/src/kube2msb/vendor/google.golang.org/cloud/compute/metadata/metadata.go @@ -0,0 +1,382 @@ +// 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" + "strings" + "sync" + "time" + + "golang.org/x/net/context" + "golang.org/x/net/context/ctxhttp" + + "google.golang.org/cloud/internal" +) + +// metadataIP is the documented metadata server IP address. +const metadataIP = "169.254.169.254" + +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("GCE_METADATA_HOST") + 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 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 + onGCE.v = testOnGCE() + return onGCE.v +} + +func testOnGCE() bool { + ctx, cancel := context.WithCancel(context.Background()) + defer cancel() + + resc := make(chan bool, 2) + + // Try two strategies in parallel. + // See https://github.com/GoogleCloudPlatform/gcloud-golang/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) + }() + + return <-resc +} + +// 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 +} |