Capture output and classify nonzero status
See this course’s project requirements
A local supervisor for two harmless supplied Python scripts, with process IDs, captured output, return-code classification, timeout cleanup and a resource-limit decision record.
Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.
What to include
- Produce an owned-child lifecycle record with actual PID and explicit control scope.
- Retain an explicit bounded command/context specification and pre-launch mode rejection.
- Create an actual stdout/stderr/return-code classification matrix for successful and failed modes.
- Demonstrate bounded timeout cleanup and retain accurate interrupted-task classification.
- Document elapsed-time evidence and a clear unimplemented-resource-controls boundary.
- Deliver the owned supervisor with dynamic observations, tested lifecycle branches, and explicit resource/platform limits.
Review and revise
Use these criteria to check your work and choose what to improve.
- The implementation or declared simulation follows the supplied contract and retains inspectable original inputs.
- Normal, boundary and rejected cases are recorded with expected versus observed results.
- The changed case has a correct explanation and does not rely on hidden state.
- The project includes source, outputs, instructions and honest tool, privacy and verification limits.
Want more background?
The idea in everyday life
owned_worker.py has harmless ok, fail, and slow modes. local_supervisor.py starts only that owned Python file, captures its small output, classifies return status, and cleans it up after a bounded timeout. test-processes.py runs five checks with no outside commands or accounts.
stdout and stderr serve different channels, and exit status describes process outcome. Visible output alone does not prove success; a failing process can still print useful text.
Capture output and classify nonzero status — original worked practice
stdout and stderr serve different channels, and exit status describes process outcome. Visible output alone does not prove success; a failing process can still print useful text.
owned_worker.py has harmless ok, fail, and slow modes. local_supervisor.py starts only that owned Python file, captures its small output, classifies return status, and cleans it up after a bounded timeout. test-processes.py runs five checks with no outside commands or accounts.
1. Step 1
Run supervise("ok") and read state completed, returncode 0, and completion stdout.
You should see: The normal child succeeds.
stdout and stderr serve different channels, and exit status describes process outcome. Visible output alone does not prove success; a failing process can still print useful text.
2. Step 2
Run supervise("fail") and inspect returncode 3 and fictional validation stderr.
You should see: The failure is classified separately.
stdout and stderr serve different channels, and exit status describes process outcome. Visible output alone does not prove success; a failing process can still print useful text.
3. Step 3
Notice both modes can print their PID before exiting.
You should see: A printed PID is not a success signal.
stdout and stderr serve different channels, and exit status describes process outcome. Visible output alone does not prove success; a failing process can still print useful text.
4. Step 4
Record mode, return status, both output channels, and classification.
You should see: A success/failure evidence matrix.
stdout and stderr serve different channels, and exit status describes process outcome. Visible output alone does not prove success; a failing process can still print useful text.
What to finish
Create an actual stdout/stderr/return-code classification matrix for successful and failed modes.
Watch for this
Using any printed line as a success signal while ignoring the actual nonzero status.
How can I tell I understand it?
Demonstrate the rule: stdout and stderr serve different channels, and exit status describes process outcome. Visible output alone does not prove success; a failing process can still print useful text. Use the supplied variant to distinguish a changed result from a broken implementation.
Quick knowledge check
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Source & access notes · checked 2026-10-01
Relevant documented module/API behavior inspected during expansion authoring; actual execution evidence is recorded separately. No grant eligibility is established.
Access: Official page retrieved with the web reader on 2026-10-01. Documentation reading does not certify execution in every native tool or browser.
Reuse: Original local practice files, fictional data, worked examples and questions. Concepts paraphrased and linked; source exercises are not copied.
Source & access notes · checked 2026-10-01
Relevant documented module/API behavior inspected during expansion authoring; actual execution evidence is recorded separately. No grant eligibility is established.
Access: Official page retrieved with the web reader on 2026-10-01. Documentation reading does not certify execution in every native tool or browser.
Reuse: Original local practice files, fictional data, worked examples and questions. Concepts paraphrased and linked; source exercises are not copied.
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