D33r-Gee commented at 3:31 pm on August 1, 2025: none

Add UTXO Snapshot Loading Interface and Progress Notifications

This PR implements a complete interface for loading UTXO snapshots through the GUI, including progress notifications to provide user feedback during the loading process.

Changes

Commit 1: `interfaces: expose UTXO snapshot loading in node interface`

Added a new virtual method loadSnapshot to the node interface for loading UTXO snapshots.
Updated the implementation in interfaces.cpp to activate the snapshot using the provided file and metadata.
This change enhances the user’s ability to load UTXO snapshots through the GUI.

Commit 2: `notifications: Implement snapshot load progress notifications`

Added a new signal SnapshotLoadProgress for snapshot load progress in the UI interface.
Updated the notifications interface to include a method for reporting snapshot loading progress.
Enhanced the ChainstateManager to report progress during snapshot loading.
Implemented the necessary handler in the kernel notifications to relay progress updates.
This change improves user feedback during the snapshot loading process.

Commit 3: `rpc: refactor loadtxoutset to use snapshot interface`

Updated the loadtxoutset RPC to call the new snapshot interface instead of directly working with chainstate internals.
Added getMetadata and getActivationResult methods to the snapshot interface to provide parity with the legacy RPC.
Improves modularity by consolidating snapshot handling through the interface layer.

Technical Details

The implementation includes:

UI Interface Enhancement Added SnapshotLoadProgress signal to CClientUIInterface with corresponding signal declaration and implementation.
Node Interface Added loadSnapshot virtual method to the node interface with implementation in interfaces.cpp.
Progress Notifications Implemented snapshotLoadProgress method in KernelNotifications class to relay progress updates to the UI.
Base Interface Added snapshotLoadProgress virtual method to the kernel notifications interface.

Benefits

User Experience Provides real-time feedback during UTXO snapshot loading operations.
GUI Integration Enables loading UTXO snapshots directly through the Bitcoin Core GUI.
Progress Tracking Users can monitor the progress of snapshot loading operations.
Consistent Interface Follows the existing pattern for progress notifications in the codebase.

Testing

Daemon build and launch bitcoind then with bitcoin-cli load a snapshot using:

0./bitcoin-cli -rpcclienttimeout=0 -signet loadtxoutset /path/to/utxo-snapsshot.dat

QT Widgets: build and run this draft PR in legacy gui repo
QML version: for a modern look build and run this PR in the newly updated gui-qml repo

DrahtBot added the label interfaces on Aug 1, 2025

DrahtBot commented at 3:31 pm on August 1, 2025: contributor

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33117.

Reviews

See the guideline for information on the review process.

Type	Reviewers
Concept ACK	pinheadmz
Approach ACK	TheCharlatan

If your review is incorrectly listed, please react with 👎 to this comment and the bot will ignore it on the next update.

Conflicts

Reviewers, this pull request conflicts with the following ones:

#bitcoin-core/gui/870 ([DRAFT] Expose AssumeUTXO Load Snapshot Functionality To The GUI by D33r-Gee)
#32983 (rpc: refactor: use string_view in Arg/MaybeArg by stickies-v)
#32297 (bitcoin-cli: Add -ipcconnect option by ryanofsky)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

D33r-Gee referenced this in commit 26a2e0fccb on Aug 1, 2025

D33r-Gee referenced this in commit 5e561eff75 on Aug 1, 2025

Sjors commented at 6:41 pm on August 1, 2025: member

I plan to test this soon(tm).

D33r-Gee commented at 8:54 pm on August 1, 2025: none

I plan to test this soon(tm).

Thanks @Sjors !

in src/interfaces/node.h:209 in de11e3b89f outdated

204@@ -204,6 +205,9 @@ class Node
205     //! List rpc commands.
206     virtual std::vector<std::string> listRpcCommands() = 0;
207 
208+    //! Load UTXO Snapshot.
209+    virtual bool loadSnapshot(AutoFile& afile, const node::SnapshotMetadata& metadata, bool in_memory) = 0;

ryanofsky commented at 10:00 pm on August 1, 2025:

In commit “interfaces: expose UTXO snapshot loading in node interface” (de11e3b89f8aba9a90a3419086807e5fee0f941d)

Note with #10102 if the GUI & node are running in separate processes, it could be a awkward for the gui process to create an AutoFile object and pass it to the node like this. Technically it could probably work: the AutoFile could be passed as a file descriptor or a (path, position) tuple. But it doesn’t seem like a clean separation of responsibilities if the GUI process is reading the beginning of the snapshot file and the node process is reading the rest of the file.

Probably current interface is ok, but it might be more ideal if node provided a more generic loadSnapshot method and the GUI didn’t directly access the file:

 0class Node
 1{
 2    // ...
 3    std::unique_ptr<Snapshot> loadSnapshot(const fs::path& path) = 0;
 4    // ...
 5};
 6
 7class Snapshot
 8{
 9public:
10    virtual ~Snapshot() = default;
11    node::SnapshotMetadata getMetadata() = 0;
12    bool activate() = 0;
13};

D33r-Gee commented at 11:35 pm on August 1, 2025:

Thanks for the review… will update soon addressing this

D33r-Gee commented at 4:24 pm on August 4, 2025:

with e79c50c updated the node.h and added snapshot.h to the /interfaces. Also updated interfaces.cpp with a SnapshotImpl class to process the path and extracts the metada and activate the snapshot. @ryanofsky let me know if that’s what you had in mind?

ryanofsky commented at 4:46 pm on August 4, 2025:

re: #33117 (review)

Thanks! I think b464f388197c5c31937d309d817d38c4b4849a91 is an improvement over previous de11e3b89f8aba9a90a3419086807e5fee0f941d because it passes an fs::path argument from the GUI to the node instead of an AutoFile file argument. This is nice because it lets node be fully responsible for parsing the snapshot file instead of relying on the GUI.

One comment on b464f388197c5c31937d309d817d38c4b4849a91 is that it looks like the Snapshot class is not actually necessary in its current form. The reason I suggested adding a Snapshot class above was that I thought GUI wanted to display SnapshotMetadata information before activating the snapshot, and a Snapshot class could provide separate getMetadata() and activate() methods to allow that. But since the Snapshot class only has a single activate() method in b464f388197c5c31937d309d817d38c4b4849a91, it looks like the class is unnecessary, and you could just have a plain Node::activateSnapshot(fs::path) method that returns bool instead of a Snapshot.

Any approach is fine though, so you should choose whatever seems to make the most sense.

D33r-Gee commented at 3:23 pm on August 6, 2025:

Thanks for taking a look! RE:

The reason I suggested adding a Snapshot class above was that I thought GUI wanted to display SnapshotMetadata information before activating the snapshot, and a Snapshot class could provide separate getMetadata()

I took some time to test various scenarios downstream in the gui-qml project. While we aren’t directly utilizing the snapshot data at the moment, I believe your initial instincts about introducing a Snapshot class were well-founded. This abstraction will become increasingly valuable as we begin to expose the dump/generate snapshot functionalities trough the GUI.

D33r-Gee force-pushed on Aug 4, 2025

pinheadmz commented at 2:37 pm on August 5, 2025: member

concept ACK, tested the mainnet snapshot load with the QML gui branch built on top of this

fanquake commented at 1:09 pm on August 6, 2025: member

https://github.com/bitcoin/bitcoin/actions/runs/16728433539/job/47504424705?pr=33117#step:10:445:

0D:\a\bitcoin\bitcoin\src\node\interfaces.cpp(115,40): error C2220: the following warning is treated as an error [D:\a\bitcoin\bitcoin\build\src\bitcoin_node.vcxproj]
1D:\a\bitcoin\bitcoin\src\node\interfaces.cpp(115,40): warning C4101: 'e': unreferenced local variable [D:\a\bitcoin\bitcoin\build\src\bitcoin_node.vcxproj]

D33r-Gee force-pushed on Aug 6, 2025

D33r-Gee commented at 4:48 pm on August 7, 2025: none

with 8bc4035 it has been rebased and the fuzzing CI error has been addressed

in src/node/interfaces.cpp:119 in 3c8b578836 outdated

114+            afile >> metadata;
115+        } catch (const std::exception&) {
116+            return false;
117+        }
118+
119+        auto activation_result{m_chainman.ActivateSnapshot(afile, metadata, m_in_memory)};

Sjors commented at 7:52 am on September 8, 2025:

In 3c8b578836dd0d8438a8aac81a1166df84811562 interfaces: expose UTXO snapshot loading in node interface: a good way to add test coverage to this new interface would be to use it in the loadtxoutset RPC.

For an example, see the various uses of EnsureMining(node);

D33r-Gee commented at 4:31 pm on September 8, 2025:

Thanks @Sjors for providing feedback and suggesting to add test coverage via the RPC…

Looking into it now and will update shortly

D33r-Gee commented at 4:36 pm on September 15, 2025:

a good way to add test coverage to this

refactored loadtxoutset to utilize the new snapshot interface…

Sjors commented at 7:57 am on September 8, 2025: member

At first glance this looks very reasonable. I also tested it in the (current) GUI with https://github.com/bitcoin-core/gui/pull/870

I had a similar concern as @ryanofsky about how to go about passing the snapshot file (path) over the interface. The current approach in 3c8b578836dd0d8438a8aac81a1166df84811562 is the same as how we handle wallet backups (restoreWallet), so probably fine?

TheCharlatan commented at 9:54 am on September 8, 2025: contributor

Approach ACK

D33r-Gee force-pushed on Sep 15, 2025

D33r-Gee commented at 4:34 pm on September 15, 2025: none

With 30d9bdb, the loadtxoutset RPC command has been refactored to use the snapshot interface, as suggested by @Sjors. Additionally, the interface now includes getMetadata and getActivationResult methods to ensure parity with the legacy RPC command.

interfaces: expose UTXO snapshot functionaility (loading/activate) in node interface

- Added a new virtual method `snapshot` to the node interface for loading UTXO snapshots.
- Updated the implementation in `interfaces.cpp` to activate the snapshot using a path.
- Added `snapshot.h` to src/interfaces to process the path and extract the metada
- Added `getMetadata` and `getActivationResults` methods for use by GUI and/or RPC
- Added error handling method and member variable

This change enhances the user ability to load utxo snapshots through the GUI and/or RPC

b3b85d6199

notifications: Implement snapshot load progress notifications

- Added a new signal for snapshot load progress in the UI interface.
- Updated the notifications interface to include a method for reporting snapshot loading progress.
- Enhanced the ChainstateManager to report progress during snapshot loading.
- Implemented the necessary handler in the kernel notifications to relay progress updates.

This change improves user feedback during the snapshot loading process.

cb6e3d4958

D33r-Gee force-pushed on Sep 15, 2025

D33r-Gee commented at 10:13 pm on September 15, 2025: none

with 94d68d1 RPC Error handling has been restored through the interface

rpc: Refactor loadtxoutset to utilize new node interface for UTXO snapshot loading

- Updated the loadtxoutset function to use the new node interface for loading UTXO snapshots.
- Replaced direct file handling with snapshot activation through the node interface.
- Enhanced the result object to correctly reference metadata from the snapshot.

This change streamlines the UTXO snapshot loading process and leverages the new interface capabilities.

668f98edb7

D33r-Gee force-pushed on Sep 16, 2025

DrahtBot added the label Needs rebase on Oct 24, 2025

DrahtBot commented at 6:59 pm on October 24, 2025: contributor

🐙 This pull request conflicts with the target branch and needs rebase.

Interfaces: Expose UTXO Snapshot Loading and Add Progress Notifications #33117