scottndecker scottndecker - 1 year ago 150
Python Question

AWS Lambda read contents of file in zip uploaded as source code

I have two files:


I zip those two together to create I then upload that through the AWS console to my lambda function.

The contents of config.json are various environmental variables. I need a way to read the contents of the file each time the lambda function runs, and then use the data inside to set run time variables.

How do I get my Python Lambda function to read the contents of a file, config.json, that was uploaded in the zip file with the source code?

Answer Source

Figured it out with the push in the right direction from @helloV.

At the top of the python file put "import os"

Inside your function handler put the following:

configPath = os.environ['LAMBDA_TASK_ROOT'] + "/config.json"
print("Looking for config.json at " + configPath)
configContents = open(configPath).read()
configJson = json.loads(configContents)
environment = configJson['environment']
print("Environment: " + environment)

That bit right there, line by line, does the following:

  • Get the path where the config.json file is stored
  • Print that path for viewing in CloudWatch logs
  • Open the file stored at that path, read the contents
  • Load the contents to a json object for easy navigating
  • Grab the value of one of the variables stored in the json
  • Print that for viewing in the CloudWatch logs

Here is what the config.json looks like:

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