Ralph Willgoss

Ralph Willgoss

Cloud, Code and Coffee

Cloud Architect /.Net Core, Python, Azure, AWS, CQRS, Event Sourcing, Distributed Systems

Connecting AWS Python Lambda to an Oracle Database, replacing cx_Oracle with python-oracledb

If you would like to connect an AWS python lambda to an Oracle database, there is a new package called python-oracledb which replaces the old package cx_Oracle. A search will reveal the old cx_Oracle package is difficult to install, with many work arounds and hacks - due to operating system library requirements.

A new package python-oracledb was released in May of 2022, and simplifies the installation process.
python-oracledb can run in Thin mode (the default), with an optional Thick mode requiring additional client dependencies.

More information on Thin vs Thick and upgrading from the cx_Oracle package, can be found on the python-oracledb website.
A feature comparison of python-oracledb Thin vs Thick vs cx_Oracle is also available.

Its worth noting that references to the package as python-oracledb and oracledb are used interchangeably.
The former, typically being used in documentation to distinguish it from other languages.

Installtion Trouble shooting

Error “cannot import name ‘base_impl’”

If you receive the error below, its worth checking that your package installation is correct:

{
   "errorMessage": "Unable to import module 'main': cannot import name 'base_impl' from partially initialized module 'oracledb'
    (most likely due to a circular import) (/var/task/oracledb/init.py)",
   "errorType": "Runtime.ImportModuleError",
   {snip}
}

Remember that packaging is platform dependant and ensure your build process hasn’t excluded any files.

Error “DPY-6000: cannot connect to database”

I received the following error, as the Oracle database I was trying to connect to required some encryption settings:

DPY-6000: cannot connect to database. Listener refused connection. (Similar to ORA-12660)

The error ORA-12660 indicates some Encryption settings in sqlnet.ora need to be set.
sqlnet.ora settings can only be done in Thick mode with the python-oracledb package.
See the Oracle python-oracledb documentation on the sqlnet.ora, on how this can be set.

Error “Runtime.ImportModuleError: Unable to import module ‘src’: /lib64/libc.so.6: version `GLIBC_2.28’ not found”

If you receive the following error, you need to look at what version of the cryptography library you are using:

[ERROR] Runtime.ImportModuleError: Unable to import module 'src': /lib64/libc.so.6: version `GLIBC_2.28' not found (required by /var/task/cryptography/hazmat/bindings/_rust.abi3.so)
Traceback (most recent call last):

This is a known issue with the cryptography package if you upgrade from 37.x vs 38.x.
There is more information on their github issue Add FAQ entry how to download and provide AWS Lambda bundle.

Error “DPI-1047: Cannot locate a 64-bit Oracle Client library: file too short”

This error occured when running a docker image and trying to connect to the oracle database.
This happened to me as I was transfering some files, while testing packaging from a Windows machine to a Linux machine, and the symbolic links got removed.
I got the hint from another user who had similar issues but with the node-oracledb package

References:
python-oracledb - docs
python-oracledb - github
Open Source Python Thin Driver for Oracle Database
ORA-12660: Encryption Or Crypto-checksumming Parameters Incompatible When Connecting To Application

Updated: