Code RoomDatabase connection nil return

MediumPrep Room Coding #2044

Database connection nil return

Code reviewConcurrencyCode quality & reviewMid–Senior~25 min

Review this Go lazy initializer that replaces a hand-rolled double-checked lock with sync.Once.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.

0:00 of about 25 min

Mark a line and say what kind of problem it is.0 findings

1var (

2 once sync.Once

3 db *sql.DB

4)

5

6func DB() *sql.DB {

7 once.Do(func() {

8 conn, err := sql.Open("postgres", dsn)

9 if err != nil {

10 return

11 }

12 if err := conn.Ping(); err != nil {

13 return

14 }

15 db = conn

16 })

17 return db

18}

Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.