RefreshableCredentials serializing without timezone info

[jordmantheman]

Hey boto folks -

I'm currently implementing my own CredentialsProvider that provides RefreshableCredentials. I'm having issues with code that has been working, but recently broke. I have to wonder if either one of my dependencies got bumped (although I can't prove it) or because we just entered daylight savings.

Basically, I'm always hitting this condition:

Credentials were refreshed, but the refreshed credentials are still expired.

To create my meta-data, I'm using the same(?) code used in botocore:

from datetime import datetime, timedelta
from dateutil.tz import tzlocal
expiration = datetime.now(tzlocal()) + timedelta(minutes=5)
expiration.strftime('%Y-%m-%dT%H:%M:%SZ')

'2016-04-07T10:26:04Z'

This doesn't encode my local time zone information, as %Z is needed.

I can demonstrate this inconsistency using some of the internal boto funcs

from botocore.credentials import _local_now, _serialize_if_needed, _parse_if_needed
now = _local_now()
print now
serialized = _serialize_if_needed(now)
print serialized
deserialized = _parse_if_needed(serialized)
print deserialized
print now - deserialized

2016-04-07 10:24:12.336556-04:00
2016-04-07T10:24:12Z
2016-04-07 10:24:12+00:00
4:00:00.336556

I can fix this issue on my end by encoding the timezone information in my format string '%Y-%m-%dT%H:%M:%S%Z', but I'm convinced botocore should do the same in its default time serialization code

TL;DR
It seems like your time_fetcher is using a timezone aware (tzlocal) datetime, but you're losing the timezone information upon serialization, defaulting to UTC. So in my case, it's comparing EST to UTC when determining expiration time.

[jordmantheman]

Let me add some versions...
Python 2.7.11
botocore (1.3.29)
python-dateutil (2.4.1)

[JordonPhillips]

Nice catch! Maybe this could also solve aws/aws-cli#1611? I'll get on it!