ceph-csi/vendor/github.com/aws/aws-sdk-go-v2/aws/credential_cache.go
Rakshith R 4f0bb2315b rbd: add aws-sts-metdata encryption type
With Amazon STS and kubernetes cluster is configured with
OIDC identity provider, credentials to access Amazon KMS
can be fetched using oidc-token(serviceaccount token).
Each tenant/namespace needs to create a secret with aws region,
role and CMK ARN.
Ceph-CSI will assume the given role with oidc token and access
aws KMS, with given CMK to encrypt/decrypt DEK which will stored
in the image metdata.

Refer: https://docs.aws.amazon.com/STS/latest/APIReference/welcome.html
Resolves: #2879

Signed-off-by: Rakshith R <rar@redhat.com>
2022-03-16 07:29:56 +00:00

140 lines
4.4 KiB
Go

package aws
import (
"context"
"sync/atomic"
"time"
sdkrand "github.com/aws/aws-sdk-go-v2/internal/rand"
"github.com/aws/aws-sdk-go-v2/internal/sync/singleflight"
)
// CredentialsCacheOptions are the options
type CredentialsCacheOptions struct {
// ExpiryWindow will allow the credentials to trigger refreshing prior to
// the credentials actually expiring. This is beneficial so race conditions
// with expiring credentials do not cause request to fail unexpectedly
// due to ExpiredTokenException exceptions.
//
// An ExpiryWindow of 10s would cause calls to IsExpired() to return true
// 10 seconds before the credentials are actually expired. This can cause an
// increased number of requests to refresh the credentials to occur.
//
// If ExpiryWindow is 0 or less it will be ignored.
ExpiryWindow time.Duration
// ExpiryWindowJitterFrac provides a mechanism for randomizing the expiration of credentials
// within the configured ExpiryWindow by a random percentage. Valid values are between 0.0 and 1.0.
//
// As an example if ExpiryWindow is 60 seconds and ExpiryWindowJitterFrac is 0.5 then credentials will be set to
// expire between 30 to 60 seconds prior to their actual expiration time.
//
// If ExpiryWindow is 0 or less then ExpiryWindowJitterFrac is ignored.
// If ExpiryWindowJitterFrac is 0 then no randomization will be applied to the window.
// If ExpiryWindowJitterFrac < 0 the value will be treated as 0.
// If ExpiryWindowJitterFrac > 1 the value will be treated as 1.
ExpiryWindowJitterFrac float64
}
// CredentialsCache provides caching and concurrency safe credentials retrieval
// via the provider's retrieve method.
type CredentialsCache struct {
// provider is the CredentialProvider implementation to be wrapped by the CredentialCache.
provider CredentialsProvider
options CredentialsCacheOptions
creds atomic.Value
sf singleflight.Group
}
// NewCredentialsCache returns a CredentialsCache that wraps provider. Provider is expected to not be nil. A variadic
// list of one or more functions can be provided to modify the CredentialsCache configuration. This allows for
// configuration of credential expiry window and jitter.
func NewCredentialsCache(provider CredentialsProvider, optFns ...func(options *CredentialsCacheOptions)) *CredentialsCache {
options := CredentialsCacheOptions{}
for _, fn := range optFns {
fn(&options)
}
if options.ExpiryWindow < 0 {
options.ExpiryWindow = 0
}
if options.ExpiryWindowJitterFrac < 0 {
options.ExpiryWindowJitterFrac = 0
} else if options.ExpiryWindowJitterFrac > 1 {
options.ExpiryWindowJitterFrac = 1
}
return &CredentialsCache{
provider: provider,
options: options,
}
}
// Retrieve returns the credentials. If the credentials have already been
// retrieved, and not expired the cached credentials will be returned. If the
// credentials have not been retrieved yet, or expired the provider's Retrieve
// method will be called.
//
// Returns and error if the provider's retrieve method returns an error.
func (p *CredentialsCache) Retrieve(ctx context.Context) (Credentials, error) {
if creds := p.getCreds(); creds != nil {
return *creds, nil
}
resCh := p.sf.DoChan("", func() (interface{}, error) {
return p.singleRetrieve(&suppressedContext{ctx})
})
select {
case res := <-resCh:
return res.Val.(Credentials), res.Err
case <-ctx.Done():
return Credentials{}, &RequestCanceledError{Err: ctx.Err()}
}
}
func (p *CredentialsCache) singleRetrieve(ctx context.Context) (interface{}, error) {
if creds := p.getCreds(); creds != nil {
return *creds, nil
}
creds, err := p.provider.Retrieve(ctx)
if err == nil {
if creds.CanExpire {
randFloat64, err := sdkrand.CryptoRandFloat64()
if err != nil {
return Credentials{}, err
}
jitter := time.Duration(randFloat64 * p.options.ExpiryWindowJitterFrac * float64(p.options.ExpiryWindow))
creds.Expires = creds.Expires.Add(-(p.options.ExpiryWindow - jitter))
}
p.creds.Store(&creds)
}
return creds, err
}
func (p *CredentialsCache) getCreds() *Credentials {
v := p.creds.Load()
if v == nil {
return nil
}
c := v.(*Credentials)
if c != nil && c.HasKeys() && !c.Expired() {
return c
}
return nil
}
// Invalidate will invalidate the cached credentials. The next call to Retrieve
// will cause the provider's Retrieve method to be called.
func (p *CredentialsCache) Invalidate() {
p.creds.Store((*Credentials)(nil))
}