Persistency CFT [2025-07-17, 2:30 - 4:00 pm]

[guysagnes]

Agenda

Participants

@guysagnes
@umaucher
@vinodreddy-g
@sorinmold
@Ahmed-Elsaka-JC
@joshualicht

Team Feedback

• Updated entry page

  • Persistency CFG General Information

• Pull Requests

  • https://github.com/eclipse-score/inc_mw_per/pulls?q=is%3Apr+is%3Aclosed

• Open actions

  • https://github.com/eclipse-score/inc_mw_per/pulls
  • https://github.com/eclipse-score/score/pull/1069/commits

Persistency

• Persistency KVS Requirements Collector #1442

TL / Arch Meeting Feedback

• Reorganization

  • Handover from @guysagnes to @SorinMoldoveanu/@vBogandB

• TL discussion

  • TL workshop: planning #1387
    • Point addressed : Mono repo or multiple repo - background related to alignment with process approach.
    • Bazel build may be addressed for evaluation in context of the Reference Integration.

• Report from other FT

  • Testing: Piotr Korkus reports that was issue identified in context of the KVS Rust implementation
    • reported in context of the Integration Test Criteria verification

• Process / Safety

  • @PandaeDo will support for FAQ - part of the invitees

JSON Parser

• JSON Library Requirements Collector #1439

[guysagnes]

KVS Rust - Review feedback

Pull Request and review expectation

Missing alignment about the different PR ongoing from QORIX
We need to align about the review and API definition
API has to be review on Persistency FT level
Structure changes inside the file system has to be review inside Persistency FT level
Target:
Keep interoperability between the implementation
Compatibility and maintenance over the versions

Feedback to the pull requests

Remove "tempdir" dev dep and "TempDir" from common.rs #36
❌ Structure on file system changed and do not follow aligned approach
Add CIT workflow to CI #37
✅ add workflow
Fix issues reported by cargo clippy #38
⚠️ interface change for Rust
Add non-generic get_value implementation #39
⚠️ interface change for Rust - alignment with C++
[CIT] Supported datatypes tests #40
✅ add test for datatypes
[CIT] snapshots tests #41
⚠️ interface change, does not respect the defined proposition
impl: restructure to multiple files #43
✅: split of the modules files by classes
Testing - workflow update, default values tests, multiple instances tests #44
✅ extended tests

Open pull requests

kvs: implement single key reset with default fallback # 32
🆗 extension of the API identified in issue reports
Decouple dependencies of json #45
⚠️ Dependency and interface change
Support basic types #46
⚠️ Interface change
bm test: Added initial setup for google benchmark tests #47
🆗 Extension of implementation - benchmark aspects
test: execute CIT with Bazel #48
🆗 Extension for CIT

[guysagnes]

eclipse-score/inc_mw_per#45
⚠️ Dependency and interface change

Propose to get aligned with baselibs to provide the Json Libs Rust in its context.
@vinodreddy-g create the pull request
@umaucher will align with the baseLibs FT

[guysagnes]

eclipse-score/inc_mw_per#46
⚠️ Interface change

• adaptation impact the deployed json file content
  • documentation of the JSON - Prototype structure. As content from KVS generic documentation
• missing meta data for the version
• dependency to the json backend
  • proposition use directly the jsontiny

[Ahmed-Elsaka-JC]

i want to discuss the following two points :

• score::Result Kvs::get_value(const std::string_view key) return KeyNotFound in case key not found without checking default values.
• add configuration parameters to builder class like (KVS_MAX_SNAPSHOTS, ./data_folder , etc) or having configuration file.

[guysagnes]

The application is defining the default value.
In case the key was not written actively the get_value() will return the default in case it exist else KeyNotFound.
The usecase get_value_default() can be explicitely accessed.

[guysagnes]

Alignment about configuration parameters - central system or on component level.

• KVS_MAX_SNAPSHOTS
• ./data_folder

The application specific folder for the data can be created in context of KVS.
Reference to definition of the folder application definition:
eclipse-score/inc_mw_per#7 (comment)

[umaucher]

review of eclipse-score/inc_mw_per#47 (basic setup for google benchmark usage and show case adler32 cpp improvement)

[vinodreddy-g]

Align on C++ vs Rust KVS API Differences (review- generated from copilot)

API Coverage Table

API Method	C++ Args / Return Type	Rust Args / Return Type	Present in C++	Present in Rust	Functional Difference / Notes
open	process_name, InstanceId, OpenNeedDefaults, OpenNeedKvs → Result	InstanceId, OpenNeedDefaults, OpenNeedKvs, Option → Result<Self, ErrorCode>	✔	✔	Rust supports optional directory; C++ uses process name
set_flush_on_exit / flush_on_exit	bool → void	&self, bool → ()	✔	✔	Rust uses trait method, C++ is direct method
reset	→ ResultBlank	&self → Result<(), ErrorCode>	✔	✔	Return types equivalent
get_all_keys	→ Result<vector<string_view>>	&self → Result<Vec, ErrorCode>	✔	✔	C++ returns string_view, Rust returns owned String
key_exists	string_view → Result	&self, &str → Result<bool, ErrorCode>	✔	✔	Args are string_view vs &str
get_value	string_view → Result	&self, &str → Result<KvsValue, ErrorCode>	✔	✔	Args and return types equivalent
get_default_value	string_view → Result	&self, &str → Result<KvsValue, ErrorCode>	✔	✔	Args and return types equivalent
set_value	string_view, KvsValue& → ResultBlank	&self, S: Into, V: Into → Result<(), ErrorCode>	✔	✔	Rust is generic over key/value types
remove_key	string_view → ResultBlank	&self, &str → Result<(), ErrorCode>	✔	✔	Args and return types equivalent
flush	→ ResultBlank	&self → Result<(), ErrorCode>	✔	✔	Return types equivalent
snapshot_count	→ size_t	&self → usize	✔	✔	Return types equivalent
snapshot_max_count	→ size_t	→ usize	✔	✔	Return types equivalent
snapshot_restore	SnapshotId& → ResultBlank	&self, SnapshotId → Result<(), ErrorCode>	✔	✔	Args and return types equivalent
get_kvs_filename	SnapshotId& → string	&self, SnapshotId → Result<PathBuf, ErrorCode>	✔	✔	C++ returns string, Rust returns PathBuf in Result
get_kvs_hash_filename	SnapshotId& → string	&self, SnapshotId → Result<PathBuf, ErrorCode>	✔	✔	C++ returns string, Rust returns PathBuf in Result
reset_key	string_view → ResultBlank	-	✔		Only in C++: Reset key to default
has_default_value	string_view → Result	-	✔		Only in C++: Check if key has default
set_default_value	string_view, KvsValue& → ResultBlank	-	✔		Only in C++: Set default value
flush_default	→ ResultBlank	-	✔		Only in C++: Flush default values
get_value_as	-	&self, &str → Result<T, ErrorCode>		✔	Only in Rust: Type conversion using TryFrom
is_value_default	-	&self, &str → Result<bool, ErrorCode>		✔	Only in Rust: Check if value is default

[guysagnes]

Difference identification not reliable - Copilot identify documentation comment as API definition.

Deviation between Rust and C++ reported in context of the review page - kvs: adapted review points in library and tests by sbachmann-qorix · Pull Request #7 · eclipse-score/inc_mw_per

get_value_as( ) part of the alignment done on 17.07.2025 -

• this function is the legacy implementation based on additional type information. (obsolete / to be removed)

Reply in context of the Persistency FT Meeting on 24.07.2025

[joshualicht]

If there is still time left/For next week: Align on the implementation separation of single and multi-threaded

[guysagnes]

information about the investigation for the configuration of threat safe mutex

1. Reference from system - check WSL
2. Double implement of the Mutex.
3. Get_Value single thread - no Mutex
4. Get_Value with if case - mutex initialization
5. Get_Value with if case and generated mutex

Proposition for the team:

• provide a single implementation
• support of the multiple thread

Aligned with
@guysagnes
@sorinmold
@PandaeDo
@joshualicht
@vbogdanb
@umaucher
@Elsaka-Ahmed-JC