From 967befa56b868f0a1690f31d32804c98726e14e6 Mon Sep 17 00:00:00 2001 From: "jian.han" Date: Thu, 18 Jan 2018 16:44:13 +1000 Subject: [PATCH 1/4] some basic example of how pointer works ,etc.. --- concurrency/subtasks/main.go | 51 ++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) diff --git a/concurrency/subtasks/main.go b/concurrency/subtasks/main.go index ab8f7d2..3c03aca 100644 --- a/concurrency/subtasks/main.go +++ b/concurrency/subtasks/main.go @@ -1,8 +1,55 @@ package main -import "github.com/jianhan/go-patterns/concurrency/subtasks/fetchers" +import ( + "errors" + + "github.com/davecgh/go-spew/spew" +) + +type Person struct { + Name string +} + +type Dog struct { + Name string +} + +type House struct { + person *Person + dog *Dog +} func main() { // divide_and_conquer.RunDivideAndConquer() - fetchers.RunFetchers() + // fetchers.RunFetchers() + // h := &House{} + // spew.Dump(h) + + // go func() { + // defer fmt.Println("Returned") + // for { + // select { + // default: + // return + // } + // } + // fmt.Println("TEST") + // }() + // time.Sleep(time.Second) + // spew.Dump(caller()) + // spew.Dump(nakedReturn()) +} + +func nakedReturn() (i uint32, err error) { + return 12, errors.New("Test") +} + +func caller() (d *Dog, err error) { + p, err := produceErr() + spew.Dump(p) + return +} + +func produceErr() (*Person, error) { + return &Person{Name: "James"}, errors.New("New Error") } From fc102d573fe3e0fdbaaced3b1a1c98ebace1e48f Mon Sep 17 00:00:00 2001 From: "jian.han" Date: Fri, 19 Jan 2018 09:28:56 +1000 Subject: [PATCH 2/4] added iota constants --- .../basic_channel_error_handling/main.go | 52 +++++++++++++++++++ idiom/iota_const/main.go | 22 ++++++++ 2 files changed, 74 insertions(+) create mode 100644 concurrency/basic_channel_error_handling/main.go create mode 100644 idiom/iota_const/main.go diff --git a/concurrency/basic_channel_error_handling/main.go b/concurrency/basic_channel_error_handling/main.go new file mode 100644 index 0000000..29523b4 --- /dev/null +++ b/concurrency/basic_channel_error_handling/main.go @@ -0,0 +1,52 @@ +package main + +import ( + "fmt" + "math/rand" + "time" +) + +func fetchAll() error { + var N = 4 + quit := make(chan bool) + errc := make(chan error) + done := make(chan error) + for i := 0; i < N; i++ { + go func(i int) { + // dummy fetch + time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond) + err := error(nil) + if rand.Intn(2) == 0 { + err = fmt.Errorf("goroutine %d's error returned", i) + } + ch := done // we'll send to done if nil error and to errc otherwise + if err != nil { + ch = errc + } + select { + case ch <- err: + return + case <-quit: + return + } + }(i) + } + count := 0 + for { + select { + case err := <-errc: + close(quit) + return err + case <-done: + count++ + if count == N { + return nil // got all N signals, so there was no error + } + } + } +} + +func main() { + rand.Seed(time.Now().UnixNano()) + fmt.Println(fetchAll()) +} diff --git a/idiom/iota_const/main.go b/idiom/iota_const/main.go new file mode 100644 index 0000000..6f94d86 --- /dev/null +++ b/idiom/iota_const/main.go @@ -0,0 +1,22 @@ +package main + +import "github.com/davecgh/go-spew/spew" + +type FeedLockLinkType int + +const ( + Racing FeedLockLinkType = iota + Market +) + +var feedLockLinkTypes = [...]string{ + "racing.Races.raceID", + "racing.Markets.marketID", +} + +func (f FeedLockLinkType) String() string { return feedLockLinkTypes[f] } + +func main() { + test := FeedLockLinkType(Racing) + spew.Dump(test) +} From df6196b7a102237cc23ae4f709038c8b0d5bc4b5 Mon Sep 17 00:00:00 2001 From: "jian.han" Date: Fri, 19 Jan 2018 15:17:32 +1000 Subject: [PATCH 3/4] demo on how to output string --- idiom/iota_const/main.go | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/idiom/iota_const/main.go b/idiom/iota_const/main.go index 6f94d86..411ee6e 100644 --- a/idiom/iota_const/main.go +++ b/idiom/iota_const/main.go @@ -17,6 +17,6 @@ var feedLockLinkTypes = [...]string{ func (f FeedLockLinkType) String() string { return feedLockLinkTypes[f] } func main() { - test := FeedLockLinkType(Racing) + test := FeedLockLinkType(Racing).String() spew.Dump(test) } From 93cce988bbf4bb9067933071762b07edd1da55c2 Mon Sep 17 00:00:00 2001 From: "jian.han" Date: Fri, 19 Jan 2018 16:25:24 +1000 Subject: [PATCH 4/4] select channel with error handling --- concurrency/.DS_Store | Bin 0 -> 6148 bytes concurrency/goroutine_leak/main.go | 1 + concurrency/select_error_handling/main.go | 65 ++++++++++++++++++++++ 3 files changed, 66 insertions(+) create mode 100644 concurrency/.DS_Store create mode 100644 concurrency/select_error_handling/main.go diff --git a/concurrency/.DS_Store b/concurrency/.DS_Store new file mode 100644 index 0000000000000000000000000000000000000000..acbcfefca556348b9b8c202905543b5a59b74efd GIT binary patch literal 6148 zcmeHK%Sr=55Ukc50$y?vJkBrp2TO=wkPnDrBnn{z@p0apzistH*{}#Xd64SRT{}Hp zGi)8U(*SJwzP$w&0OoW@e0rFg@4HXzqB2IL^NdHlVS^_e`8&^?dyQ9e_Vh9Tz%w>@ z#shk6x%)!geXNiD{?PC8#`CUFl@yQyQa}nw0Vyz2z0pQvfH-41jL$Jk5Su56UEz?(49${COsdt0VM%AcRb5v&BqkkJ!-v()RuhWF z?L5ClIjl=mlmb%VRDsJ}F1-KW(SMo$Pf1!y0V(jW6tLN9y;|~>s<%#F&U0}d&)n|{hs2;WA9SMr2)HgXDexBxd;ty-8EOCk literal 0 HcmV?d00001 diff --git a/concurrency/goroutine_leak/main.go b/concurrency/goroutine_leak/main.go index ad2e5c4..3109b03 100644 --- a/concurrency/goroutine_leak/main.go +++ b/concurrency/goroutine_leak/main.go @@ -20,6 +20,7 @@ goroutines in some sort of organized fashion. **/ func main() { + resourceLeak() cancellationSignal() } diff --git a/concurrency/select_error_handling/main.go b/concurrency/select_error_handling/main.go new file mode 100644 index 0000000..91c2886 --- /dev/null +++ b/concurrency/select_error_handling/main.go @@ -0,0 +1,65 @@ +package main + +import ( + "fmt" + "time" + + "github.com/davecgh/go-spew/spew" +) + +func main() { + if err := selectWithErrorDemo(); err != nil { + spew.Dump(err) + } + time.Sleep(time.Second * 5) +} + +func selectWithErrorDemo() error { + // start update race and market + count, errChan, doneChan := 2, make(chan error), make(chan bool) + + go func() { + // update race + if err := doFirstThing(); err != nil { + errChan <- err + } else { + doneChan <- true + fmt.Println("Finish First Go Routine") + } + + }() + + go func() { + // update market + if err := doSecondThing(); err != nil { + errChan <- err + } else { + doneChan <- true + fmt.Println("Finish Second Go Routine") + } + }() + + for i := 0; i < count; i++ { + select { + case err := <-errChan: + return err + case d := <-doneChan: + spew.Dump(i, d) + } + } + return nil +} + +func doFirstThing() error { + time.Sleep(time.Second * 2) + fmt.Println("Exectue Do First") + return nil + +} + +func doSecondThing() error { + time.Sleep(time.Second * 1) + fmt.Println("Exectue Do Second") + // return errors.New("Error In Second") + return nil +}