Snapshot verification

[engelmi]

Summary by Sourcery

Implement snapshot endianness verification, refactor GGUF parsing for clearer endianness detection, and improve robustness of snapshot creation and cleanup flows.

New Features:

• Add dedicated endianness verification methods to ModelStore including a public verify_snapshot API

Enhancements:

• Refactor GGUF parser to separate model endianness detection from overall parsing
• Harden snapshot creation with cleanup on HTTP and generic errors and wrap ref-file deletion to ignore missing files
• Simplify snapshot pull logic in repo_model_base and ollama modules by removing redundant try/except blocks

[sourcery-ai]

Reviewer's Guide

Introduces a dedicated snapshot verification step for model endianness, centralizes GGUF parsing logic and system endianness helpers, refactors snapshot creation with robust error handling and automatic cleanup, and removes redundant code and parameters across model store and client wrappers.

Sequence Diagram for Updated new_snapshot Process in ModelStore

sequenceDiagram
    participant Client
    participant ModelStore

    Client->>ModelStore: new_snapshot(model_tag, snapshot_hash, files)
    activate ModelStore
    Note over ModelStore: Try: Create snapshot
    ModelStore->>ModelStore: _prepare_new_snapshot(...)
    ModelStore->>ModelStore: _download_snapshot_files(...)
    ModelStore->>ModelStore: _ensure_chat_template(...)
    opt On Exception during creation
        ModelStore->>ModelStore: remove_snapshot(model_tag)  // Cleanup
        ModelStore-->>Client: Raise Exception
    end

    Note over ModelStore: Try: Verify snapshot
    ModelStore->>ModelStore: verify_snapshot(model_tag)
    opt On EndianMismatchError during verification
        ModelStore->>ModelStore: remove_snapshot(model_tag)  // Cleanup
        ModelStore-->>Client: Raise EndianMismatchError
    end

    deactivate ModelStore
    Client-->>ModelStore: (Snapshot created and verified or error handled)

Loading

Sequence Diagram for verify_snapshot and Endianness Check

sequenceDiagram
    participant ModelStore
    participant GGUFInfoParser
    participant EndianUtils

    ModelStore->>ModelStore: verify_snapshot(model_tag)
    activate ModelStore
    ModelStore->>ModelStore: _verify_endianess(model_tag)
    activate ModelStore # _verify_endianess
    ModelStore->>ModelStore: get_ref_file(model_tag)
    ModelStore->>ModelStore: get_blob_file_path(model_hash)
    ModelStore->>GGUFInfoParser: is_model_gguf(model_path)
    GGUFInfoParser-->>ModelStore: is_gguf
    alt is_gguf is true
        ModelStore->>GGUFInfoParser: get_model_endianness(model_path)
        GGUFInfoParser-->>ModelStore: model_endianness
        ModelStore->>EndianUtils: get_system_endianness()
        EndianUtils-->>ModelStore: host_endianness
        alt host_endianness != model_endianness
            ModelStore-->>ModelStore: Raise EndianMismatchError
        end
    end
    deactivate ModelStore # _verify_endianess
    ModelStore->>ModelStore: _store.verify_snapshot() // Verifies other aspects
    deactivate ModelStore

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File-Level Changes

Change	Details	Files
Introduce dedicated snapshot endianness verification step	Add _verify_endianess and verify_snapshot methods Invoke verification after snapshot creation and cleanup on failure Raise EndianMismatchError on mismatch	ramalama/model_store.py
Centralize GGUF endianness determination and system helper functions	Extract get_model_endianness from GGUFInfoParser Adjust parse to defer magic and version reading using unified endianness Add get_system_endianness helper Define custom EndianMismatchError for consistent error reporting	ramalama/gguf_parser.py ramalama/endian.py
Refactor new_snapshot to wrap steps in error-handling and ensure cleanup	Wrap preparation, download, and template setup in try/except blocks Remove snapshot and ref files on HTTPError and generic exceptions Chain verify_snapshot call with cleanup on mismatch	ramalama/model_store.py
Improve error handling in remove_snapshot	Catch and ignore FileNotFoundError when removing missing ref file	ramalama/model_store.py
Eliminate redundant endianness flags and simplify client wrappers	Remove should_verify_endianness parameter from SnapshotFile constructors Delete inline endianness checks in _download_snapshot_files Remove redundant exception wrappers around new_snapshot in repo_model_base and ollama	ramalama/model_store.py ramalama/repo_model_base.py ramalama/ollama.py

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[taronaeo]

Hi, when this PR is ready, please allow me to test it on IBM Z & LinuxONE as well to ensure that the endianness checks are still intact :)

Self-assigning for now

[engelmi]

Hi, when this PR is ready, please allow me to test it on IBM Z & LinuxONE as well to ensure that the endianness checks are still intact :)

Self-assigning for now

@taronaeo Ping :)
Would be great if you can test it on IBM Z + LinuxONE.

[sourcery-ai]

Hey @engelmi - I've reviewed your changes - here's some feedback:

• In _verify_endianess, replace the if ref_file is None: pass with an explicit early return to make the no-ref_file case clearer and prevent accidental fallthrough.
• The generic except Exception block in new_snapshot can mask unexpected bugs—consider catching only the specific errors you expect or re-raising after cleanup to preserve the original traceback.
• You have almost identical cleanup logic in both error handlers in new_snapshot—extracting that into a small helper function could reduce duplication and make the flow clearer.

Here's what I looked at during the review

• 🟡 General issues: 1 issue found
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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[taronaeo]

Hi, when this PR is ready, please allow me to test it on IBM Z & LinuxONE as well to ensure that the endianness checks are still intact :)
Self-assigning for now

@taronaeo Ping :) Would be great if you can test it on IBM Z + LinuxONE.

Gotcha! I have dispatched a runner to test this PR, will update again once the test is complete :)

[taronaeo]

LGTM! Works as intended on IBM Z & LinuxONE!