Permission issue when deploying Serverless Python app

user_1858664 0
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I have a Serverless Python app and I am trying to deploy it using sls deploy. The serverless.yml is as follows.

service: update-register

provider:
  name: aws
  runtime: python3.8
  profile: haumi
  stage: ${opt:stage, 'staging'}
  environment: ${file(environment.yml):${self:provider.stage}}
  region: ${self:provider.environment.REGION}

  iamRoleStatements:
    # para poder leer y escribir en el bucket
    - Effect: "Allow"
      Action:
        - "sqs:SendMessage"
      Resource: "*"

functions:
  update:
    handler: handler.update
    events:
      - sqs: ${self:provider.environment.AWS_SQS_QUEUE}

The handler file is like this:

def update(event, context):
    print("=== event: ", event)

However when I try to deploy and trigger the update function the following error appears in AWS Cloudwatch

[ERROR] PermissionError: [Errno 13] Permission denied: '/var/task/handler.py'
Traceback (most recent call last):
  File "/var/lang/lib/python3.8/imp.py", line 300, in find_module
    with open(file_path, 'rb') as file:

I tried changing the permissions of this file but I can't. Any ideas?

aws-lambda serverless amazon-web-services
2 Answers

This issue had nothing to do with Serverless but with the permissions of my mounted NTFS partition in Ubuntu 18.04.

tl;dr Change /etc/fstab to of the mounted partition to

UUID=8646486646485957 /home/Data      ntfs    defaults,auto,umask=002,uid=1000,gid=1000 0       0

Use id -u to get the uid and gid.

The long explanation

What I found out is that in an NTFS partition you cannot just change a file permissions with chmod. You require to configure the mask while mounting the partition. Since I mount the partition upon booting Ubuntu, the required change was in my fstab file. The umask parameter determines which permissions cannot be set. You can find more information about this parameter here.

After you do this reboot. You will find that the files have a different permission. In my case the permissions that allowed my deployed code to work were

-rwxrwxr-x 1 user group   59 jul 24 00:47 handler.py*

I am sure there are issues by allowing others to execute the file. But this solved the issue.

user_18586640

Another cause for the exact same error:

[ERROR] PermissionError: [Errno 13] Permission denied: '/var/task/<my_lambda_python_file>.py'
Traceback (most recent call last):
  File "/var/lang/lib/python3.8/imp.py", line 300, in find_module
    with open(file_path, 'rb') as file:

I was deploying the Lambda using Atlassian Bamboo, and Bamboo seemed to be messing with the permissions of the files that make up the lambda:

-rw-r-----@  1 <user>  <group>   2.5K 19 Nov 18:10 <my_lambda_python_file>.py

I worked around this problem by adding to the Bamboo script:

chmod 755 <my_lambda_python_file>.py

just before bundling the code into a zip file.

user_66292800
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