feat(indexworker): add max users threshold for rollout

[fadymak]

Adds max users threshold config value to allow for a managed rollout.

┌──────────────────────────────┬───────────────────┬──────────────────────────────────────────────────────────────┐
│ EnsureUserSearchIndexesExist │ MaxUsersThreshold │ Behavior │
├──────────────────────────────┼───────────────────┼──────────────────────────────────────────────────────────────┤
│ false │ 0 │ Default — nothing happens │
├──────────────────────────────┼───────────────────┼──────────────────────────────────────────────────────────────┤
│ true │ 0 │ User opt-in — always creates indexes │
├──────────────────────────────┼───────────────────┼──────────────────────────────────────────────────────────────┤
│ true │ >0 │ User opt-in — always creates indexes (threshold ignored) │
├──────────────────────────────┼───────────────────┼──────────────────────────────────────────────────────────────┤
│ false │ >0 │ Progressive rollout — creates only if user count ≤ threshold │
└──────────────────────────────┴───────────────────┴──────────────────────────────────────────────────────────────┘

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📝 Walkthrough

Summary by CodeRabbit

• New Features
  • Introduced configurable user count threshold for user search indexes, enabling conditional index creation based on instance size with an option for forced index creation regardless of threshold.

Walkthrough

Added a numeric gating mechanism for creating user-search indexes. A new configuration field MaxUsersThreshold (exposed via GOTRUE_INDEX_WORKER_MAX_USERS_THRESHOLD) was added to IndexWorkerConfiguration. The API worker now considers this threshold when deciding to invoke index creation. The index worker queries an approximate user count when the threshold is active and, if the count exceeds the threshold and the boolean opt-in EnsureUserSearchIndexesExist is false, it skips index creation and logs an index_creation_skipped event; otherwise it proceeds with index creation. Tests exercising these cases were added.

Sequence Diagram(s)

sequenceDiagram
participant API as APIWorker
participant IW as IndexWorker
participant DB as Database
participant Log as Logger
API->>IW: maybeCreateIndexes(ctx)
IW->>IW: check cfg.IndexWorker.EnsureUserSearchIndexesExist\nand cfg.IndexWorker.MaxUsersThreshold
alt EnsureUserSearchIndexesExist == true
IW->>Log: log "index_creation_starting" (opt-in)
IW->>DB: acquire advisory lock / create indexes
DB-->>IW: index creation result
IW->>Log: log result or error
else MaxUsersThreshold > 0 and EnsureUserSearchIndexesExist == false
IW->>DB: query approximate users count
DB-->>IW: returns userCount
alt userCount > MaxUsersThreshold
IW->>Log: log "index_creation_skipped" with userCount and threshold
else
IW->>Log: log "index_creation_starting" with userCount
IW->>DB: acquire advisory lock / create indexes
DB-->>IW: index creation result
IW->>Log: log result or error
end
else
IW->>Log: log "index_creation_starting"
IW->>DB: acquire advisory lock / create indexes
DB-->>IW: index creation result
IW->>Log: log result or error
end

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🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding a max users threshold configuration to the index worker for managing rollout of index creation.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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[cstockton]

Is it possible to remove the default of 0 to mean any, and instead make "any" be something like math.MaxInt64? My main concern being if something sets enabled to true expecting an accompanying threshold to be set, but it doesn't and the default of 0 means any.

Approving ahead of time to keep you unblocked.

[fadymak]

Thanks @cstockton — I agree, I've decided to simplify the config and make the 2 configuration variables independent of one another:

1. ensure_user_search_indexes_exist: signifies explicit user opt-in (always creates indexes if true)
2. max_users_threshold: configurable threshold to set an upper bound for # of users (0 = disabled, will only run if number of users < threshold)

[coveralls]

Pull Request Test Coverage Report for Build 22075075135

Details

• 15 of 18(83.33%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 69.034%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
internal/api/apiworker/apiworker.go	0	1	0.0%
internal/indexworker/indexworker.go	15	17	88.24%

Totals
Change from base Build 22072312968:	0.01%
Covered Lines:	14941
Relevant Lines:	21643

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💛 - Coveralls