[gsoc26] Updated FW upgrader metadata extraction

[nemesifier]

Updated FW upgrader metadata extraction with new information found during research.

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📥 Commits

Reviewing files that changed from the base of the PR and between 2910a5c and 39161fe.

📒 Files selected for processing (1)

• developer/gsoc-ideas-2026.rst

Walkthrough

This change revises the GSoC 2026 idea "Automatic Extraction of OpenWrt Firmware Image Metadata" to specify a primary extraction path that reads embedded fwtool-generated JSON from sysupgrade images and a fallback path that attempts kernel/DTB decompression and parsing for non-fwtool images. It adds implementation notes on memory and safe decompression, clarifies retry and crash behavior (no auto-retries; crashes treated as failures with manual intervention), and updates terminology and contributor guidance for extensibility across OpenWrt derivatives.

Sequence Diagram(s)

mermaid
sequenceDiagram
participant User as User
participant Service as MetadataExtractor
participant Image as FirmwareImage
participant FWTool as fwtoolJSON
participant Fallback as Decompressor/DTBParser
User->>Service: Submit firmware image
Service->>Image: Inspect for fwtool JSON
alt fwtool JSON present
Image->>FWTool: Read embedded JSON
FWTool-->>Service: Return metadata
Service-->>User: Metadata result
else fwtool JSON absent
Service->>Fallback: Decompress kernel/locate DTB
Fallback-->>Service: Parsed metadata or failure
Service-->>User: Metadata result or manual-entry prompt
end

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related issues

• [feature] Automatic extraction of image metadata from OpenWrt firmware images openwisp-firmware-upgrader#378 — Implements the same fwtool JSON primary extraction and fallback decompression/DTB parsing, plus task/error handling and upgrader-class design.

Possibly related PRs

• [docs] GSoC 26 improvements, roadmap FW upgrader UX updates #265 — Modifies the same docs section and discusses firmware image metadata extraction and extractor/upgrader class extensibility.
• [gsoc26] Automatic Extraction of OpenWrt Firmware Image Metadata #264 — Earlier PR that introduced automatic OpenWrt firmware metadata extraction ideas; this change refines that proposal with fwtool primary + fallback and error/memory handling.

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title '[gsoc26] Updated FW upgrader metadata extraction' directly relates to the main changes in the PR, which focus on revising the firmware upgrader metadata extraction approach with new primary and fallback methods.
Description check	✅ Passed	The description 'Updated FW upgrader metadata extraction with new information found during research' is related to the changeset, which documents new metadata extraction strategies for OpenWrt images.

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch gsoc26-metadata

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@developer/gsoc-ideas-2026.rst`:
- Around line 324-349: Fix the backtick formatting in the "Non-``sysupgrade``
images" bullet: replace the malformed four-backtick sequence around "x86" (shown
as ````x86````) with the correct two-backtick inline code format so it reads
``x86``, ``armvirt`` (locate the phrase "Non-``sysupgrade`` images" / the
fragment containing ````x86````, ``armvirt`` to make the change).

🧹 Nitpick comments (2)

developer/gsoc-ideas-2026.rst (2)

243-254: Strong extensibility guidance with minor style inconsistency.

The upgrader class architecture provides clear guidance for supporting OpenWrt derivatives and potential future operating systems. The requirement that each upgrader class have a corresponding metadata extraction class establishes good separation of concerns.

Minor: Hyphenation inconsistency

Line 254 uses "meta-data" while the rest of the document consistently uses "metadata" (unhyphenated). Consider standardizing:

-Each upgrader class must have a related meta-data extraction class.
+Each upgrader class must have a related metadata extraction class.

---

285-306: Comprehensive research findings with minor style inconsistencies.

The research findings provide valuable context about fwtool metadata, image types, and edge cases. The guidance is technically sound and helps contributors understand the problem space.

Minor: Inconsistent capitalization

Lines 289 and 300 use capitalized "Sysupgrade" and "Rootfs" at the start of sentences, but these are technical terms that appear lowercase elsewhere in the document (e.g., line 104 "sysupgrade", line 114 "non-sysupgrade"). Consider using lowercase with backticks for consistency:

-- **``Sysupgrade`` vs disk images**: Only ``sysupgrade`` images contain
+- **``sysupgrade`` vs disk images**: Only ``sysupgrade`` images contain
   ``fwtool`` metadata. ``x86`` and ``armvirt`` images are disk images and

-- ``Rootfs`` images (``*-squashfs-rootfs.img``) are **not suitable for
+- ``rootfs`` images (``*-squashfs-rootfs.img``) are **not suitable for

📜 Review details

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Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 5a40a12 and 1ef79fc.

📒 Files selected for processing (1)

• developer/gsoc-ideas-2026.rst

🔇 Additional comments (3)

developer/gsoc-ideas-2026.rst (3)

103-123: LGTM! Clear distinction between primary and fallback extraction methods.

The updated approach clearly separates the fwtool-based primary method from fallback strategies, provides concrete metadata field mappings, and includes a reference implementation. The guidance for x86/armvirt edge cases and the call for contributor research on other targets is appropriate for a GSoC proposal.

---

206-231: Implementation guidance is comprehensive and security-conscious.

The distinction between fast fwtool extraction and resource-intensive fallback methods is clear. Memory management considerations (configurable limits, OOM notifications, zip bomb prevention) appropriately address security concerns for a system processing uploaded images.

---

236-241: LGTM! Pragmatic retry and crash handling policies.

The no-retry policy for extraction failures is appropriate since extraction errors are typically deterministic (format issues, unsupported types) rather than transient. Treating crashes as failures with user notification aligns well with the draft/unconfirmed workflow.

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