metadata

package
Version: v0.97.0 Latest Latest
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Published: Sep 29, 2021 License: Apache-2.0 Imports: 15 Imported by: 923

Documentation

Overview

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.

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func Email added in v0.45.0

func Email(serviceAccount string) (string, error)

Email calls Client.Email on the default client.

func ExternalIP

func ExternalIP() (string, error)

ExternalIP returns the instance's primary external (public) IP address.

func Get

func Get(suffix string) (string, error)

Get calls Client.Get on the default client.

func Hostname

func Hostname() (string, error)

Hostname returns the instance's hostname. This will be of the form "<instanceID>.c.<projID>.internal".

func InstanceAttributeValue

func InstanceAttributeValue(attr string) (string, error)

InstanceAttributeValue calls Client.InstanceAttributeValue on the default client.

func InstanceAttributes

func InstanceAttributes() ([]string, error)

InstanceAttributes calls Client.InstanceAttributes on the default client.

func InstanceID

func InstanceID() (string, error)

InstanceID returns the current VM's numeric instance ID.

func InstanceName

func InstanceName() (string, error)

InstanceName returns the current VM's instance ID string.

func InstanceTags

func InstanceTags() ([]string, error)

InstanceTags returns the list of user-defined instance tags, assigned when initially creating a GCE instance.

func InternalIP

func InternalIP() (string, error)

InternalIP returns the instance's primary internal IP address.

func NumericProjectID

func NumericProjectID() (string, error)

NumericProjectID returns the current instance's numeric project ID.

func OnGCE

func OnGCE() bool

OnGCE reports whether this process is running on Google Compute Engine.

func ProjectAttributeValue

func ProjectAttributeValue(attr string) (string, error)

ProjectAttributeValue calls Client.ProjectAttributeValue on the default client.

func ProjectAttributes

func ProjectAttributes() ([]string, error)

ProjectAttributes calls Client.ProjectAttributes on the default client.

func ProjectID

func ProjectID() (string, error)

ProjectID returns the current instance's project ID string.

func Scopes

func Scopes(serviceAccount string) ([]string, error)

Scopes calls Client.Scopes on the default client.

func Subscribe

func Subscribe(suffix string, fn func(v string, ok bool) error) error

Subscribe calls Client.Subscribe on the default client.

func Zone

func Zone() (string, error)

Zone returns the current VM's zone, such as "us-central1-b".

Types

type Client added in v0.24.0

type Client struct {
	// contains filtered or unexported fields
}

A Client provides metadata.

func NewClient added in v0.24.0

func NewClient(c *http.Client) *Client

NewClient returns a Client that can be used to fetch metadata. Returns the client that uses the specified http.Client for HTTP requests. If nil is specified, returns the default client.

Example

This example demonstrates how to use your own transport when using this package.

package main

import (
	"net/http"

	"cloud.google.com/go/compute/metadata"
)

// This example demonstrates how to use your own transport when using this package.
func main() {
	c := metadata.NewClient(&http.Client{Transport: userAgentTransport{
		userAgent: "my-user-agent",
		base:      http.DefaultTransport,
	}})
	p, err := c.ProjectID()
	if err != nil {
		// TODO: Handle error.
	}
	_ = p // TODO: Use p.
}

// userAgentTransport sets the User-Agent header before calling base.
type userAgentTransport struct {
	userAgent string
	base      http.RoundTripper
}

// RoundTrip implements the http.RoundTripper interface.
func (t userAgentTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	req.Header.Set("User-Agent", t.userAgent)
	return t.base.RoundTrip(req)
}
Output:

func (*Client) Email added in v0.45.0

func (c *Client) Email(serviceAccount string) (string, error)

Email returns the email address associated with the service account. The account may be empty or the string "default" to use the instance's main account.

func (*Client) ExternalIP added in v0.24.0

func (c *Client) ExternalIP() (string, error)

ExternalIP returns the instance's primary external (public) IP address.

func (*Client) Get added in v0.24.0

func (c *Client) Get(suffix string) (string, error)

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 (*Client) Hostname added in v0.24.0

func (c *Client) Hostname() (string, error)

Hostname returns the instance's hostname. This will be of the form "<instanceID>.c.<projID>.internal".

func (*Client) InstanceAttributeValue added in v0.24.0

func (c *Client) InstanceAttributeValue(attr string) (string, error)

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 (*Client) InstanceAttributes added in v0.24.0

func (c *Client) InstanceAttributes() ([]string, error)

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 (*Client) InstanceID added in v0.24.0

func (c *Client) InstanceID() (string, error)

InstanceID returns the current VM's numeric instance ID.

func (*Client) InstanceName added in v0.24.0

func (c *Client) InstanceName() (string, error)

InstanceName returns the current VM's instance ID string.

func (*Client) InstanceTags added in v0.24.0

func (c *Client) InstanceTags() ([]string, error)

InstanceTags returns the list of user-defined instance tags, assigned when initially creating a GCE instance.

func (*Client) InternalIP added in v0.24.0

func (c *Client) InternalIP() (string, error)

InternalIP returns the instance's primary internal IP address.

func (*Client) NumericProjectID added in v0.24.0

func (c *Client) NumericProjectID() (string, error)

NumericProjectID returns the current instance's numeric project ID.

func (*Client) ProjectAttributeValue added in v0.24.0

func (c *Client) ProjectAttributeValue(attr string) (string, error)

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 (*Client) ProjectAttributes added in v0.24.0

func (c *Client) ProjectAttributes() ([]string, error)

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 (*Client) ProjectID added in v0.24.0

func (c *Client) ProjectID() (string, error)

ProjectID returns the current instance's project ID string.

func (*Client) Scopes added in v0.24.0

func (c *Client) Scopes(serviceAccount string) ([]string, error)

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 (*Client) Subscribe added in v0.24.0

func (c *Client) Subscribe(suffix string, fn func(v string, ok bool) error) error

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 (*Client) Zone added in v0.24.0

func (c *Client) Zone() (string, error)

Zone returns the current VM's zone, such as "us-central1-b".

type Error added in v0.35.0

type Error struct {
	// Code is the HTTP response status code.
	Code int
	// Message is the server response message.
	Message string
}

Error contains an error response from the server.

func (*Error) Error added in v0.35.0

func (e *Error) Error() string

type NotDefinedError

type NotDefinedError string

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.

func (NotDefinedError) Error

func (suffix NotDefinedError) Error() string

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