This repo provides the instructions and the cx_Oracle layer (python 3.7 version) that can be used as a Lambda Layer on AWS. To skip the steps and use the lambda layer directly, download the zip file from https://drive.google.com/file/d/15gYtlo2qzL_OFjICSfNLkNSZ1IFF_1tK/view?usp=sharing.

cx_Oracle is a Python extension module that enables access to Oracle Database. See the cx_Oracle’s documentation. Here are the steps of how to create a cx_Oracle lambda layer (steps referenced from https://github.com/dennisoft/cxoracle).

1. EC2 Instance

   • Launch an Amazon EC2 Instance with Amazon Linux 2 AMI.The reason for using Amazon Linux 2 is that it comes with Python 3.7 available in the repositories.
   • Now you can connect to your Linux Instance using an SSH Client and start building the AWS Lambda Layer.

2. Install and configure the AWS CLI.

3. Update the existing system packages and install Python 3.7

    $ sudo yum update -y 
    $ sudo yum install python3 -y
   

4. Create a working directory and structure it by creating the "python" and "lib" folders which are required for a Python Layer.

    $ mkdir ~/my_layer
    $ cd ~/my_layer
    $ mkdir python/ lib/
   

5. Install the "cx_Oracle" module using "pip-3.7" under "python/" directory. The function code will access it without additional configuration.

   $ pip-3.7 install cx_Oracle -t python/

6. Download the Oracle Instant Client (version 18.5 Basic Light) and extract the contents to the "lib/" directory.

    $ wget https://download.oracle.com/otn_software/linux/instantclient/185000/instantclient-basiclite-linux.x64-18.5.0.0.0dbru.zip -O oracle.zip
    $ unzip -j oracle.zip -d lib/
   

7. Install the "libaio" library and copy it to the "lib/" folder of the layer. This library is preinstalled in Amazon Linux 2, if you are using it ycan skip the installation.

   $ (optional) sudo yum install libaio -y
   $ cp /lib64/libaio.so.1 lib/libaio.so.1
   

8. Create a ZIP archive with "python/" and "lib/" folders.

   $ zip -r -y layer.zip python/ lib/
   

9. Create a layer using the lambda layer zip file

10. Upload the lambda layer to AWS and add environment variable to the lambda function:

    LD_LIBRARY_PATH = /var/lang/lib:/lib64:/usr/lib64:/var/runtime:/var/runtime/lib:/var/task:/var/task/lib:/opt/lib:/opt/python