Running Pro*COBOL Programs in Kubernetes

A Proof of Concept (PoC) for building and running Pro*COBOL programs in containers for deployment on Kubernetes.

This project demonstrates how to containerize and run a Pro*COBOL application with Oracle database connectivity in a modern Kubernetes environment. It leverages several open-source tools to create a fully containerized workflow.

• melange - For building packages
• apko - For building container images
• k3d - For running a local Kubernetes cluster
• kubectl - For interacting with Kubernetes
• maru - For running tasks
• Docker runtime
• Oracle Instant Client libraries (see below)

Due to Oracle licensing restrictions, you need to download the Oracle Instant Client files yourself. See the detailed instructions in src/libs/README.md for:

• Direct download links for the required packages
• Oracle account and license agreement requirements
• Specific version information and compatibility notes
• Proper placement of the downloaded files

The required files are:

• instantclient-basic-linux.x64-19.27.0.0.0dbru.zip
• instantclient-precomp-linux.x64-19.27.0.0.0dbru.zip

• src/cobolite.pco - The Pro*COBOL example application source code
• src/container.yaml - Configuration for building the container image
• src/package.yaml - Configuration for building the Wolfi package
• src/pipelines/procob.yaml - Pipeline for compiling Pro*COBOL code
• manifests/ - Kubernetes deployment manifests
  • database.yaml - Oracle database deployment
  • worker.yaml - COBOL application deployment

1. The Pro*COBOL source code is pre-compiled and compiled using the Oracle Instant Client and GNU COBOL
2. Melange builds a package with the compiled COBOL program and its dependencies
3. Apko creates a minimal container image with the package
4. K3d deploys a local Kubernetes cluster with:
   • An Oracle database container
   • A COBOL worker container that connects to the database

The full development workflow can be run with:

This command will:

1. Check for required tools
2. Generate necessary keys for Melange
3. Build the COBOL package
4. Build a container image
5. Deploy to a local k3d Kubernetes cluster
6. Run the COBOL application

The sample application (cobolite.pco) demonstrates:

• Connecting to an Oracle database using Pro*COBOL
• Retrieving environment variables for configuration
• Executing SQL queries
• Reading from and writing to files
• Processing command-line arguments

It can run in two modes:

• import - Reads data from a file and inserts it into the database
• export - Exports data from the database to a file (default mode in the demo)

To modify the application:

1. Edit src/cobolite.pco
2. Run maru run dev to rebuild and deploy

To change database connection details, modify the environment variables in manifests/worker.yaml.

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.