WIP: IAM Assume Role and ECR Login (awscli)

A simple way to assume a different role and login to ECR Inspired from here

aws sts assume-role --role-arn "arn:aws:iam::123456789012:role/example-role" --role-session-name AWSCLI-Session

will return a json similar to:

{
    "AssumedRoleUser": {
        "AssumedRoleId": "AROA3XFRBF535PLBIFPI4:s3-access-example",
        "Arn": "arn:aws:iam::123456789012:role/example-role"
    },
    "Credentials": {
        "SecretAccessKey": "9drTJvcXLB89EXAMPLELB8923FB892xMFI",
        "SessionToken": "AQoXdzELDDY//////////wEaoAK1wvxJY12r2IrDFT2IvAzTCn3zHoZ7YNtpiQLF0MqZye/qwjzP2iEXAMPLEbw/m3hsj8VBTkPORGvr9jM5sgP+w9IZWZnU+LWhmg+a5fDi2oTGUYcdg9uexQ4mtCHIHfi4citgqZTgco40Yqr4lIlo4V2b2Dyauk0eYFNebHtYlFVgAUj+7Indz3LU0aTWk1WKIjHmmMCIoTkyYp/k7kUG7moeEYKSitwQIi6Gjn+nyzM+PtoA3685ixzv0R7i5rjQi0YE0lf1oeie3bDiNHncmzosRM6SFiPzSvp6h/32xQuZsjcypmwsPSDtTPYcs0+YN/8BRi2/IcrxSpnWEXAMPLEXSDFTAQAM6Dl9zR0tXoybnlrZIwMLlMi1Kcgo5OytwU=",
        "Expiration": "2016-03-15T00:05:07Z",
        "AccessKeyId": "ASIAJEXAMPLEXEG2JICEA"
    }
}

manually set the env variables or use this oneliner

eval `aws sts assume-role --role-arn "arn:aws:iam::123456789012:role/example-role" --role-session-name AWSCLI-Session | jq -r '"export AWS_ACCESS_KEY_ID=" + .Credentials.AccessKeyId, "export AWS_SECRET_ACCESS_KEY="+.Credentials.SecretAccessKey, "export AWS_SESSION_TOKEN="+.Credentials.SessionToken'`

once you have the new variables set, you can login to ECR as you normally do:

$(aws ecr get-login --registry-ids 012345678910)

This could be easily be integrated in a shell step in Jenkins pipeline / job:

...
withAwsCli(credentialsId: 'some-credentials') {
    sh '''
    eval `aws sts assume-role --role-arn "arn:aws:iam::123456789012:role/example-role" --role-session-name AWSCLI-Session | jq -r '"export AWS_ACCESS_KEY_ID=" + .Credentials.AccessKeyId, "export AWS_SECRET_ACCESS_KEY="+.Credentials.SecretAccessKey, "export AWS_SESSION_TOKEN="+.Credentials.SessionToken'`
    $(aws ecr get-login --registry-ids 012345678910)
    docker push 012345678910.dkr.ecr.eu-west-1.amazonaws.com/some/image:tag
    '''
}