2相コミットなどの実例に見るゴルーチンとチャネルの使いどころ

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1. 2 Koji Aomatsu 2021 . 11 . 1 3 .
4. # 2 視 視 1 : N
5. # iOS Go Go 
 
 # GO API
7. # Cloud SQL Datastore # DB # 2
8. # 2 Begin, Prepare, Commit XA Transaction , 2 MySQL PostgreSQL
9. # 視 DB 規 # 視
10. channel goroutine 1 goroutine 2 視 Datastore Cloud SQL
11. # 視 視 sync.WaitGroup 規 // Cloud SQL -> Datastore // ॲཧ201͕ऴΘͬͨ͜ͱΛ஌ΒͤΔ c1 := make(chan int) // Cloud SQL -> Datastore // ॲཧ202Ͱબ୒͞Εͨঢ়ଶΛ఻͑Δ c2 := make(chan int) // Cloud SQL -> Datastore // Prepare (err != nil ͳΒࣦഊ͍ͯ͠Δ) dbPrepareCh := make(chan error) // Datastore -> Cloud SQL // DatastoreͷτϥϯβΫγϣϯ݁Ռ dbTxResultCh := make(chan error, 1)
12. channel goroutine 1 goroutine 2 視 Datastore Cloud SQL
13. // Datastore go func() { defer close(dsTxResultCh) begin() doSomething(101) <-c1 doSomething(102) state := <-c2 doSomething(state) // Prepare err := <-dbPrepareCh if err != nil { dsTxResultCh <- err rollback() } else { err = commit() dsTxResultCh <- err } }() # defer 視 dbPrepareCh
14. // Datastore go func() { ... doSomething(101) _, ok := <-c1 if !ok { rollback() return } doSomething(102) state := <-c2 err := doSomething(state) if err != nil { rollback() // ϒϩοΫΛղআ͢Δඞཁ͕ग़Δ <-dbPrepareCh return } ... }() # select
15. channel goroutine 1 goroutine 2 視 Datastore Cloud SQL
16. // Cloud SQL go func() { defer close(c1) defer close(c2) defer close(dbPrepareCh) begin() doSomething(201) c1 <- 0 doSomething(202) c2 <- SomeState err := doSomething(203) dbPrepareCh <- err err = <-dsTxResultCh if err != nil { commit() } else { rollback() } }() # defer dbPrepareCh Prepare dsTxResultCh Datastore
17. # #
18. # 規 規
20. # API # 視 #
21. # API 30 GAE 10% # runtime.NumGoroutine() 10%
22. # // 3000ඵ͔͔Δ func handle1() { for i := 0; i < 1000; i++ { send(i) } } // 3ඵͰऴΘΔ func handle2() { for i := 0; i < 1000; i++ { go send(i) } } func send(num int) { time.Sleep(3 * time.Second) fmt.Printf("sent %v\n", num) }
23. # func handle() { c := make(chan int, 300) go func() { defer close(c) for i := 0; i < 10000; i++ { c <- i } }() var wg sync.WaitGroup for i := 0; i < 100; i++ { wg.Add(1) go func() { defer wg.Done() for { num, ok := <-c if !ok { return } send(num) } }() } wg.Wait() }
24. # 1
25. # API GAE Context log
27. # 規 視 2 3 1
28. # API DB
29. Thank you for watching. Twitter @kojiaomatsu