DateTime::ComputeCurrentTimestampInAmazonFormat() should use system_clock

[skirill]

Visual Studio 2013

double DateTime::ComputeCurrentTimestampInAmazonFormat()
{
    std::chrono::duration<double, std::chrono::seconds::period> now = std::chrono::high_resolution_clock::now().time_since_epoch();
    return now.count();
}

this returned 6-digit numbers in range ~265000 for me while current epoch time is a 10-digit number around 1446523779. In fact high_resolution_clock's epoch is it's host start time, hot Jan 1, 1970 (UNIX epoch), thus using its time_since_epoch in AWS timestamp comparisons makes no sense. To use UNIX epoch, system_clock should be used in place of high_resolution_clock.

For me this bug resulted in not refreshing temporary Cognito identity tokens upon their expiration because here:

bool CognitoCachingCredentialsProvider::IsTimeExpired(double expiry)
{
    using namespace std::chrono;
    //30s grace buffer so requests have time to finish before expiry.
    static const double GRACE_BUFFER = 30.0;   

    return expiry < (Utils::DateTime::ComputeCurrentTimestampInAmazonFormat() - GRACE_BUFFER);
}

right side of a comparison was always less than 10-digit expiry epoch time returned by AWS server. I've checked that if I use system_clock the problem disappears.

[JonathanHenson]

We made this change and pushed it several weeks ago. Have you pulled latest? e8309dc

[skirill]

You are right, sorry, I was using an outdated snapshot.