Add ExpiryWindow and ExpiryWindowJitterFrac to CredentialsCache

[skmcgrail]

Refactors the credential providers to remove ExpiryWindow behavior to the CredentialsCache. Adds a ExpiryWindowJitterFrac capability to the CredentialsCache to support the addition of jitter the configured refresh window.

Fixes: #940

[innovia]

@skmcgrail

i'm having a super hard time, trying to get this to work, with this new change

https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/credentials/stscreds#hdr-Assume_Role

can you please share here an example of how to assume role with the service client?

[skotambkar]

Hi @innovia, could you describe the issue are you facing?

Our migration guide has an example on how to assume a role. Please take a look - https://aws.github.io/aws-sdk-go-v2/docs/migrating/#assumerole .

[innovia]

@skmcgrail thanks for the link,

I am using okta was and have different roles to assume per environment, I'm gonna try the link you referenced

[innovia]

@skmcgrail I couldn't get it to work from the docs, they are very unclear...

this code (which i found by digging into github open source codes) works but is undocumented

if assumeRoleArn != "" {
    stsClient := sts.Client(t)
    creds := stscreds.NewAssumeRoleProvider(stsClient, assumeRoleArn)
    awsConfig.Credentials = creds
  }

  client := ec2.NewFromConfig(awsConfig)

but according to the doc this code should be used. but its unclear:

  if assumeRoleArn != "" {
    stsClient := sts.Client(t)
    creds := stscreds.NewAssumeRoleProvider(stsClient, assumeRoleArn)
    value, crErr := creds.Retrieve(ctx)
    if crErr != nil {
      return nil, fmt.Errorf("error retrieving credentials from sts: %+v", crErr)
    }
    awsConfig.Credentials = value
  }

it's very confusing because if I check the type of awsConfig.Credentials it's CredentialsProvider which is an interface to Retrieve but the result is this error that takes me in circles

cannot use value (type aws.Credentials) as type aws.CredentialsProvider