Overview ▾

Package plugincreds implements a credentials provider sourced from a Go plugin. This package allows you to use a Go plugin to retrieve AWS credentials for the SDK to use for service API calls.

As of Go 1.8 plugins are only supported on the Linux platform.

Plugin Symbol Name

The "GetAWSSDKCredentialProvider" is the symbol name that will be used to lookup the credentials provider getter from the plugin. If you want to use a custom symbol name you should use GetPluginProviderFnsByName to lookup the symbol by a custom name.

This symbol is a function that returns two additional functions. One to retrieve the credentials, and another to determine if the credentials have expired.

Plugin Symbol Signature

The plugin credential provider requires the symbol to match the following signature.

func() (RetrieveFn func() (key, secret, token string, err error), IsExpiredFn func() bool)

Plugin Implementation Example

The following is an example implementation of a SDK credential provider using the plugin provider in this package. See the SDK's example/aws/credential/plugincreds/plugin folder for a runnable example of this.

package main

func main() {}

var myCredProvider provider

// Build: go build -o plugin.so -buildmode=plugin plugin.go
func init() {
	// Initialize a mock credential provider with stubs
	myCredProvider = provider{"a","b","c"}
}

// GetAWSSDKCredentialProvider is the symbol SDK will lookup and use to
// get the credential provider's retrieve and isExpired functions.
func GetAWSSDKCredentialProvider() (func() (key, secret, token string, err error), func() bool) {
	return myCredProvider.Retrieve,	myCredProvider.IsExpired
}

// mock implementation of a type that returns retrieves credentials and
// returns if they have expired.
type provider struct {
	key, secret, token string
}

func (p provider) Retrieve() (key, secret, token string, err error) {
	return p.key, p.secret, p.token, nil
}

func (p *provider) IsExpired() bool {
	return false;
}

Configuring SDK for Plugin Credentials

To configure the SDK to use a plugin's credential provider you'll need to first open the plugin file using the plugin standard library package. Once you have a handle to the plugin you can use the NewCredentials function of this package to create a new credentials.Credentials value that can be set as the credentials loader of a Session or Config. See the SDK's example/aws/credential/plugincreds folder for a runnable example of this.

// Open plugin, and load it into the process.
p, err := plugin.Open("somefile.so")
if err != nil {
	return nil, err
}

// Create a new Credentials value which will source the provider's Retrieve
// and IsExpired functions from the plugin.
creds, err := plugincreds.NewCredentials(p)
if err != nil {
	return nil, err
}

// Example to configure a Session with the newly created credentials that
// will be sourced using the plugin's functionality.
sess := session.Must(session.NewSession(&aws.Config{
	Credentials:  creds,
}))

Index ▾

Package files

provider.go