Roll your own AWS Lambda in 5 easy steps

Below we walk though a very simple example of writing your own serverless code / Lambda functions from a Linux workstation.

Lambda Languages

AWS Lambda currently supports the following languages:

  • C# versions 1,2, & 2.1
  • Go version 1
  • Java version 8
  • Node versions 4, 6 & 8
  • Python versions 2 & 3

It is advisable that you at least know one of these programming scripting languages before you begin with any Lamba code.

For demonstration purposes we will continue with python3.

Lambda Creation

Step 1 — Create a workspace

mkdir my_lambda_module

Step 2 — Create lambda_function.py

Assuming we are creating a python-based lambda function:

touch my_lamba_module/lambda_function.py

Step 3 — Install any missing/prerequisite modules:

pip3 install <module> -t ./my_lamba_module

Step 4 — Code

Code away using your favourite IDE or text editor, or import a pre-programmed lambda from github. Don’t forget to install any missing modules.

Step 5 — Package it:

cd my_lambda_module;zip -r my_lambda.zip *

Goto the AWS console and open your lambda function, click ‘Edit Code Inline’, and change to ‘Upload a .ZIP file’

You code should appear after clicking ‘Save’

Finally

It is always a good idea to ‘Test’ you code before going straight into production; It may help to have a few print() statements to help you debug any issues through Cloudwatch logs.

Any missing modules can be rectified by repeating the install module above, simply re-zip, and re-upload until your happy your lambda code is functioning correctly.

Originally published at www.netscylla.com on September 2, 2018.

Netscylla Cyber Security

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Interesting thoughts and opinions from the field of cyber security in general, focusing mainly on penetration testing and red-teaming.

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