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I'm writing a lambda function that works with datetimes and trying to import pytz so I can have timezone be accounted for when comparing.

import boto3
import pytz
from datetime import timedelta, date, datetime
from boto3.dynamodb.conditions import Key, Attr

causes this to display

{errorMessage=Unable to import module 'lambda_function'}

but when I remove import pytz the function fires (it just doesn't work properly without timezone info)

Scott Decker
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4 Answers4

19

If you don't have access to pytz in your environment, maybe you have access to python-dateutil. In that case you can do:

import datetime
import dateutil.tz

eastern = dateutil.tz.gettz('US/Eastern')
datetime.datetime.now(tz=eastern)

REF. How to get current time in Pacific Timezone when import pytz fails?

assembler
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yarick
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14

You need to install the pytz package so it's available for your lambda. The way you do this is having pip install it into the directory you are going to zip and upload to AWS (i.e. peered with the file containing your lambda function).

pip install -t path/to/your/lambda pytz

Then when you zip it up and upload it, it will be available.

Editing to add that I created a tool to do a lot of this for you - you can find it here: https://github.com/jimjkelly/lambda-deploy

jimjkelly
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  • I was hoping to avoid this, but I have a feeling you're probably correct. I'm going to try and find another way to accomplish my end goal, but marking as correct answer for now. much thanks. – Scott Decker Jan 20 '16 at 17:42
  • I've actually been working on a tool to kind of do this automatically (as well as handle pushing it up to AWS for you), but I haven't pushed it up to github just yet. The big pain comes when you are working with libraries with compiled bits. :/ – jimjkelly Jan 20 '16 at 17:44
2

To follow up on @cheframzi's answer to "Package a pytz zip file in the format python/pytz/..." as a Lambda Layer, here is one way to do that.

mkdir python
pip3 install -t python pytz=='2019.2'
zip -r pytz.zip python
rm -rf python

And then you can use aws lambda publish-layer-version --layer-name <layer_name> --zip-file fileb://./pytz.zip to deploy a new version of the layer.

As long as the library is installed at the python/pytz level of the zip file, AWS Lambda should be able to find it. You can also put it inside python/lib/python3.8/site-packages\pytz though for your specific python runtime version per here: https://docs.aws.amazon.com/lambda/latest/dg/configuration-layers.html

fred271828
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1

I ran into this issue today. The way I solved is

  • Package a pytz zip file in the format python/pytz/... the library file
  • Created a Lambda Layer enter image description here
  • In my lambda used the above layer
cheframzi
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