AWS Lambda and S3

Below are a couple of problems I ran into when writing a Python 2.7 Lambda function that created a file and then uploaded it to S3. (s3.upload_file)

  1. The file I was creating and writing to in the function was empty in S3 after the upload.
    • Turns out I needed the “( )” braces on the Python “close” command.  Silly issue, but took my like 20 minutes to figure out….
  2. In your Lambda function, you need to create your files under /tmp, which is your functions ephemeral storage.
    • fileName = ‘/tmp/’ + name

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