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Level 7 / Project 12 - Incident Mode Switch

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Focus

  • degraded mode controls during incidents

Why this project exists

This project gives you level-appropriate practice in a realistic operations context. Goal: run the baseline, alter behavior, break one assumption, recover safely, and explain the fix.

Run (copy/paste)

Use <repo-root> as the folder containing this repository's README.md.

cd <repo-root>/projects/level-7/12-incident-mode-switch
python project.py --input data/sample_input.txt --output data/output_summary.json
pytest -q

Expected terminal output

... output_summary.json written ...
2 passed

Expected artifacts

  • data/output_summary.json
  • Passing tests
  • Updated notes.md

Alter it (required)

  1. Add an auto_recover feature: if all active stages succeed, automatically transition back to normal.
  2. Add a duration() method to IncidentEvent that calculates how long the system stayed in each mode.
  3. Re-run script and tests — verify auto-recovery and duration tracking work.

Break it (required)

  1. Attempt an invalid transition (e.g. maintenance to degraded) and observe the rejection.
  2. Pass an unknown mode string (e.g. "panic") and watch the ValueError from the Enum.
  3. Capture the error and confirm the system stays in its previous valid mode.

Fix it (required)

  1. Wrap the Mode(target) conversion in a try/except to handle unknown mode strings gracefully.
  2. Return a clear error message listing valid modes when an invalid one is provided.
  3. Add tests for unknown mode strings and all invalid transition paths.

Explain it (teach-back)

  1. Why does limiting mode transitions prevent accidental state corruption?
  2. What happened when an invalid mode string was passed?
  3. How did the try/except with a helpful message improve operability?
  4. How do real incident management systems (PagerDuty, OpsGenie) model severity levels?

Mastery check

You can move on when you can: - run baseline without docs, - explain one core function line-by-line, - break and recover in one session, - keep tests passing after your change.

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