z/OS Automation: Extracting LINKLIST with Python (ZOAU)

Overview

This project demonstrates how to use Python with Z Open Automation Utilities (ZOAU) in USS to interact with z/OS system data. The script retrieves the system LINKLIST and writes it into a sequential dataset, then validates the output using a JCL job.

Objective

• Extract system-level data (LINKLIST) from z/OS
• Transform the output into the required dataset format
• Write the data into a sequential dataset
• Validate correctness using a JCL job (CC0000)

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Technologies Used

• z/OS USS (Unix System Services)
• Python 3
• ZOAU (zoautil_py)
• JCL
• VS Code with Zowe Explorer

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Key Steps

1. Dataset Preparation

• Created or reused a sequential dataset:

  Z87690.COMPLETE
  

• Used Python (datasets.create) to ensure correct dataset type

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2. Retrieve System LINKLIST

• Used ZOAU API:

  zsystem.list_linklist()

• Returned system libraries such as:

  SYS1.MIGLIB
  SYS1.CSSLIB
  SYS1.LINKLIB
  

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3. Data Transformation

• Converted Python list output into required z/OS dataset format:

  • One entry per line
  • Preserved single quotes
  • Removed list brackets and commas

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4. Write to Dataset

• Used:

  datasets.write(dsname, linklist_output, append=False)

• Ensured correct parameter order and formatting

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5. Validation

• Submitted JCL job:

  CHKAUTO
  

• Achieved:

  CC 0000
  

• Confirmed dataset content met exact formatting requirements

• Code Snapshot

This is the Python script used to extract the z/OS LINKLIST and write it to a sequential dataset.

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Challenges & Fixes

Issue: Invalid dataset name errors

• Cause: Incorrect argument order in datasets.write()
• Fix: Corrected to (dsname, data)

Issue: Validation failure (incorrect dataset content)

• Cause: Output formatting mismatch (missing quotes, brackets present)
• Fix: Reformatted output to match required structure

Issue: CC0127 errors

• Cause: Dataset format and content mismatch with validation job
• Fix: Ensured sequential dataset + exact output formatting

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Key Takeaways

• z/OS workflows require strict formatting precision, not just correct logic
• ZOAU enables direct system interaction using Python
• Understanding dataset types (PDS vs sequential) is critical
• Debugging involved tracing both data flow and system expectations

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Outcome

Successfully built an end-to-end automation workflow:

USS (Python) → ZOAU API → z/OS Dataset → JCL Validation

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Next Steps

• Extend script to automate job submission using jobs.submit()
• Explore additional ZOAU modules for system monitoring and automation