Allow --system-config to be set via CLOUDAI_SYSTEM_CONFIG env var

[shreyaskommuri]

Summary

• --system-config can now be set via a CLOUDAI_SYSTEM_CONFIG environment variable instead of always passing the flag explicitly.
• The --system-config flag still takes precedence when both are set. The requirement that one of them is provided is unchanged (click's envvar= mechanism satisfies required=True).
• Suggested by @podkidyshev as a small quality-of-life improvement while discussing the parser work tracked in Support relative-path test references and lazy-load only referenced test/hook tomls #985.
• Change is a single option definition in src/cloudai/cli/cli.py's common_options, so it applies to install, uninstall, dry-run, run, and generate-report uniformly. verify-configs does not use --system-config and is unaffected.

Test Plan

Added 3 tests to tests/test_cli.py: env-var-only resolution, flag-takes-precedence-over-env-var, and env var documented in --help across all 5 subcommands.

$ uv run pytest tests/test_cli.py -v
...
tests/test_cli.py::test_system_config_can_be_set_via_env_var PASSED
tests/test_cli.py::test_system_config_flag_takes_precedence_over_env_var PASSED
tests/test_cli.py::test_system_config_env_var_documented_in_help[install] PASSED
tests/test_cli.py::test_system_config_env_var_documented_in_help[uninstall] PASSED
tests/test_cli.py::test_system_config_env_var_documented_in_help[dry-run] PASSED
tests/test_cli.py::test_system_config_env_var_documented_in_help[run] PASSED
tests/test_cli.py::test_system_config_env_var_documented_in_help[generate-report] PASSED
...
39 passed in 0.05s

Also ran a real end-to-end dry-run using the env var instead of the flag, against the bundled sleep scenario:

$ CLOUDAI_SYSTEM_CONFIG="$(pwd)/conf/common/system/standalone_system.toml" uv run cloudai dry-run \
    --tests-dir conf/common/test \
    --test-scenario conf/common/test_scenario/sleep.toml
...
[INFO] Scenario results
╔════════════════╤════════╤════════════════════════════════════════════════════╗
║ Case           │ Status │ Details                                            ║
╟────────────────┼────────┼────────────────────────────────────────────────────╢
║ Tests.sleep1   │ PASSED │ results/.../Tests.sleep1/0                         ║
║ Tests.sleep5   │ PASSED │ results/.../Tests.sleep5/0                         ║
║ Tests.sleep5_2 │ PASSED │ results/.../Tests.sleep5_2/0                       ║
║ Tests.sleep20  │ PASSED │ results/.../Tests.sleep20/0                        ║
╚════════════════╧════════╧════════════════════════════════════════════════════╝
[INFO] All jobs are complete.

Also ran full suite (uv run pytest -q, 1806 passed), ruff check, ruff format --check, and pyright, all clean.

Additional Notes

None.

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ℹ️ Recent review info

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• src/cloudai/cli/cli.py
• tests/test_cli.py

---

📝 Walkthrough

Walkthrough

The shared --system-config CLI option now supports CLOUDAI_SYSTEM_CONFIG, with tests covering environment configuration, explicit option precedence, and help output.

Changes

System config environment support

Layer / File(s)	Summary
Add environment-backed system config option src/cloudai/cli/cli.py	The shared --system-config option accepts CLOUDAI_SYSTEM_CONFIG and documents it in the help text.
Validate CLI configuration behavior tests/test_cli.py	Tests cover environment-based configuration, explicit option precedence, and help documentation across subcommands.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: srivatsankrishnan

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: sourcing --system-config from CLOUDAI_SYSTEM_CONFIG.
Description check	✅ Passed	The description directly matches the implemented CLI env-var support, precedence behavior, and added tests.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
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Inline comments:
In `@tests/test_cli.py`:
- Around line 49-60: Strengthen test_system_config_can_be_set_via_env_var so it
asserts the expected downstream configuration-validation error produced from
system_cfg, rather than only checking that the missing-option message is absent.
Include system_cfg’s path in the assertion when that path is exposed in the CLI
output, proving CLOUDAI_SYSTEM_CONFIG was actually used.

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---

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• src/cloudai/cli/cli.py
• tests/test_cli.py