3850: Experimental features r=Kerollmops a=dureuill
# Pull Request
## Related issue
- Fixes https://github.com/meilisearch/meilisearch/issues/3857
- Related to https://github.com/meilisearch/meilisearch/issues/3771
## What does this PR do?
### Example
<details>
<summary>Using the feature to enable `scoreDetails`</summary>
```json
❯ curl \
-X POST 'http://localhost:7700/indexes/index-word-count-10-count/search' \
-H 'Content-Type: application/json' \
--data-binary '{ "q": "Batman", "limit": 1, "showRankingScoreDetails": true, "attributesToRetrieve": ["title"]}' | jsonxf
{
"message": "Computing score details requires enabling the `score details` experimental feature. See https://github.com/meilisearch/product/discussions/674",
"code": "feature_not_enabled",
"type": "invalid_request",
"link": "https://docs.meilisearch.com/errors#feature_not_enabled"
}
```
```json
❯ curl \
-X PATCH 'http://localhost:7700/experimental-features/' \
-H 'Content-Type: application/json' \
--data-binary '{
"scoreDetails": true
}'
{"scoreDetails":true,"vectorSearch":false}
```
```json
❯ curl \
-X POST 'http://localhost:7700/indexes/index-word-count-10-count/search' \
-H 'Content-Type: application/json' \
--data-binary '{ "q": "Batman", "limit": 1, "showRankingScoreDetails": true, "attributesToRetrieve": ["title"]}' | jsonxf
{
"hits": [
{
"title": "Batman",
"_rankingScoreDetails": {
"words": {
"order": 0,
"matchingWords": 1,
"maxMatchingWords": 1,
"score": 1.0
},
"typo": {
"order": 1,
"typoCount": 0,
"maxTypoCount": 1,
"score": 1.0
},
"proximity": {
"order": 2,
"score": 1.0
},
"attribute": {
"order": 3,
"attribute_ranking_order_score": 1.0,
"query_word_distance_score": 1.0,
"score": 1.0
},
"exactness": {
"order": 4,
"matchType": "exactMatch",
"score": 1.0
}
}
}
],
"query": "Batman",
"processingTimeMs": 3,
"limit": 1,
"offset": 0,
"estimatedTotalHits": 46
}
```
</details>
### User standpoint
- Add new route GET/POST/PATCH/DELETE `/experimental-features` to switch on or off some of the experimental features in a manner persistent between instance restarts
- Use these new routes to allow setting on/off the following experimental features:
- vector store **TODO:** fill in issue
- score details (related to https://github.com/meilisearch/meilisearch/issues/3771)
- Make the way of checking feature availability and error message uniform for the Prometheus metrics experimental feature
- Save the enabled features in dump, restore from dumps
- **TODO:** tests:
- Test new security permissions (do they allow access with ALL, do they prevent access when missing)
- Test dump behavior, in particular ability to import existing v6 dumps
- Test basic behavior when calling the rule
### Implementation standpoint
- New DB "experimental-features"
- dumps are modified to save the state of that new DB as a `experimental-features.json` file, that is then loaded back when importing the dump. This doesn't change the dump version, as the file is optional and it missing will not cause the dump to fail
Co-authored-by: Louis Dureuil <louis@meilisearch.com>
