fix(ci): handle empty API responses safely in azure_marketplace_publi…

[shellyco-code]

This PR fixes potential IndexError and JSONDecodeError runtime exceptions in ci-automation/release/azure_marketplace_publish.py. When fetching product or plan durable IDs from Microsoft Partner Center (get_product_durable_id and get_plan_durable_id), empty API responses or unexpected payloads caused fixed-index string splits (split("/")[1] / split("/")[2]) to throw an IndexError.

To prevent crashes during marketplace image publishing, string path splits were updated to .split("/")[-1] alongside early null-checks (if not product_durable_id: / if not plan_durable_id:) to safely skip invalid offers. Additionally, try/except error handling was wrapped around resp.json() across get_product_durable_id, get_plan_durable_id, get_image_versions, and generate_partner_center_token to validate dictionary structures before accessing response fields, and get_active_plans now falls back to returning [] if channel-info.txt cannot be fetched.

Fixes flatcar/Flatcar#2316.

How to use

Reviewers can inspect ci-automation/release/azure_marketplace_publish.py or execute the publishing script in test mode (-t / --test-mode) with Partner Center credentials to verify that missing or empty API responses for offers or plans log an error and skip cleanly without raising unhandled IndexError exceptions.

Testing done

1. Python Compilation Test:

python -m py_compile ci-automation/release/azure_marketplace_publish.py

Output: Exit code 0 (no syntax errors)

2. Automated Unit Tests:
   Executed unit tests covering valid API payloads, empty {"value": []} arrays, non-JSON HTTP responses, and variable-length ID path formats:

python test_azure_publish.py

Output:

ERROR:root:There is some issue with the channel-info.txt file. Please check https://flatcar.cdn.cncf.io/channel-info.txt
ERROR:root:Returned status code: 404
.WARNING:root:No existing vmImageVersions found for product 'prod', plan 'plan'.
.ERROR:root:Failed to fetch plan durable ID for product 'product1', plan 'plan1'. Status: 200, Response: {"value": []}
.ERROR:root:Failed to fetch product durable ID for offer 'offer1'. Status: 200, Response: {"value": []}
ERROR:root:Failed to parse JSON response for product durable ID (offer 'offer1'). Status: 200, Error: Invalid JSON
..
----------------------------------------------------------------------
Ran 5 tests in 0.008s

OK

• Changelog entries added in the respective changelog/ directory (user-facing change, bug fix, security fix, update)
• Inspected CI output for image differences: /boot and /usr size, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.

Signed-off-by: shellyco-code shellychahar57@gmail.com

[sayanchowdhury]

Thanks for the contribution @shellyco-code

Currently there is too much of duplication of the code. How about having a method like _parse_json_dict(resp, context) where the context can have all the info to build the error message.

[sayanchowdhury]

Can we leave updating the index?