Python AWS Lambda Create file in memory
If you need to create a file in a Lambda you need to write the file to /tmp because it is otherwise a read-only file system. But if you’re emailing a file there’s no need to write the file to the file system, with some minor alterations you can speed up the process and keep the file only in memory.
Current code
csv_file = 'your_file.csv'
with open(csv_file, 'w', newline='') as file:
writer = csv.DictWriter(file, fieldnames=headers)
writer.writeheader()
for item in my_data:
writer.writerow(item)
return csv_file
New code
buffer = io.StringIO()
writer = csv.DictWriter(buffer, fieldnames=headers)
writer.writeheader()
for item in my_data:
writer.writerow(item)
return buffer
and also a small tweak to your email script
Current code
attachment = MIMEBase('application', 'octet-stream')
attachment.set_payload(open(csv_file, 'rb').read())
New code
attachment = MIMEBase('application', 'octet-stream')
attachment.set_payload(csv_file.getvalue())