feat(postgres): add support for SetConnMaxLifetime

[flemzord]

Summary

This PR adds support for configuring database connection max lifetime using SetConnMaxLifetime.

Changes

• Added ConnMaxLifetime field to ConnectionOptions struct (bun/bunconnect/connect.go:23)
• Added --postgres-conn-max-lifetime CLI flag with default value of 0 (disabled)
• Added SetConnMaxLifetime() call in OpenSQLDB() when value is non-zero (bun/bunconnect/connect.go:55-57)
• Updated connection logging to include conn-max-lifetime parameter

Benefits

According to database/sql documentation, SetConnMaxLifetime sets the maximum amount of time a connection may be reused. This helps:

• Prevent stale or degraded connections from lingering in the pool
• Accommodate databases that disconnect idle sessions after extended periods
• Ensure connections are periodically refreshed rather than held indefinitely

Usage

# Set connection lifetime to 10 minutes
--postgres-conn-max-lifetime=10m

# Set connection lifetime to 1 hour
--postgres-conn-max-lifetime=1h

# Disable (default)
--postgres-conn-max-lifetime=0

Test plan

• Verify the new --postgres-conn-max-lifetime flag is available
• Test with different lifetime values (e.g., 10m, 1h)
• Verify connections are properly closed and replaced after the specified lifetime
• Check that logging includes the new connection configuration parameter

[coderabbitai]

Walkthrough

Adds a new ConnectionOptions field ConnMaxLifetime time.Duration, exposes a new flag to set it, threads the value through flag parsing into ConnectionOptions, logs the value when opening the DB, and applies it to the opened *sql.DB via SetConnMaxLifetime when non-zero.

Changes

Cohort / File(s)	Summary
Connection options and application bun/bunconnect/connect.go	Added ConnMaxLifetime time.Duration to ConnectionOptions; updated string representation to include conn-max-lifetime; when opening the DB, apply SetConnMaxLifetime on the resulting *sql.DB if ConnMaxLifetime is non-zero.
Flags / CLI wiring bun/bunconnect/flags.go	Added PostgresConnMaxLifetimeFlag constant and flag registration; parse flag as a duration and populate ConnectionOptions.ConnMaxLifetime from flags.
Logging bun/bunconnect/module.go	Added "conn-max-lifetime" field to the "opening database connection" log entry sourced from connectionOptions.ConnMaxLifetime.

Sequence Diagram(s)

sequenceDiagram
    autonumber
    participant CLI as CLI (flags)
    participant Config as ConnectionOptions
    participant Module as module.Open (logs)
    participant DB as OpenSQLDB / *sql.DB

    CLI->>Config: parse flags (includes conn-max-lifetime)
    Config->>Module: pass ConnectionOptions
    Module->>DB: OpenSQLDB(connectionOptions)
    DB->>DB: sql.Open / connector setup
    DB->>DB: SetConnMaxLifetime(conn-max-lifetime)  %% applied if non-zero
    DB-->>Module: return *sql.DB
    Module-->>CLI: log "opening database connection" (includes conn-max-lifetime)

Loading

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

• Areas to check:
  • Correct parsing and defaulting of the new duration flag in flags.go.
  • Proper threading of ConnMaxLifetime into ConnectionOptions.
  • Ensure SetConnMaxLifetime is invoked only when non-zero and does not alter existing connection parameter handling (MaxOpenConns, MaxIdleConns, ConnMaxIdleTime).
  • Verify the new log field is formatted as intended in module.go.

Poem

🐰 I nudge a flag, a tiny tweak so bright,
Conn lifetime set to keep the pool polite,
Logs whisper the span in morning's light,
Conns rest and run, just right —
Hoppity hops, dbs sleep tight.

Pre-merge checks and finishing touches

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The pull request title 'feat(postgres): add support for SetConnMaxLifetime' directly and clearly summarizes the main change in the changeset. The title accurately reflects that this PR adds support for configuring database connection maximum lifetime via SetConnMaxLifetime, which is the primary objective evidenced by the changes across all three modified files (connect.go, flags.go, and module.go).
Description check	✅ Passed	The pull request description clearly outlines the purpose of the changes: adding support for configuring database connection max lifetime using SetConnMaxLifetime. It provides specific details about what was changed (new ConnMaxLifetime field, CLI flag, SetConnMaxLifetime call, and logging updates), references official Go documentation for context, explains the benefits, shows usage examples, and includes a test plan. The description is well-organized and directly related to the changeset.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feat/postgres-conn-max-lifetime

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[codecov]

Codecov Report

❌ Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 27.63%. Comparing base (a20343d) to head (0abea09).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
bun/bunconnect/connect.go	0.00%	4 Missing ⚠️
bun/bunconnect/flags.go	0.00%	3 Missing ⚠️
bun/bunconnect/module.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #522      +/-   ##
==========================================
- Coverage   34.77%   27.63%   -7.15%     
==========================================
  Files         139      162      +23     
  Lines        6061     6605     +544     
==========================================
- Hits         2108     1825     -283     
- Misses       3842     4669     +827     
  Partials      111      111              

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