https://github.com/sun0day/async
A ES7-style async/await implementation in Golang
https://github.com/sun0day/async
Last synced: 11 days ago
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A ES7-style async/await implementation in Golang
- Host: GitHub
- URL: https://github.com/sun0day/async
- Owner: sun0day
- License: mit
- Created: 2022-08-01T07:47:35.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2022-08-03T08:48:56.000Z (almost 3 years ago)
- Last Synced: 2025-04-05T13:23:30.153Z (about 1 month ago)
- Language: Go
- Size: 12.7 KB
- Stars: 17
- Watchers: 2
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# async
A ES7-style async/await implementation lib based on Goroutine + Channel in Golang.
## Install
```shell
$ go get github.com/sun0day/async
```
## API
### `async.AsyncTask`
Async work unit created by `async.Async`.
```go
type AsyncTask[V any] struct {
Value V // execution result
Err any // execution possible error
State AsyncState // execution state
}
```
`async.AsyncTask.State` has 3 values:
- `async.PENDING`(`async.AsyncTask` is doing)
- `async.FULFILLED`(`async.AsyncTask` is done and result returns)
- `async.REJECTED`(`async.AsyncTask` is done but error happens).
### `async.Async`
Convert a synchronous `func` to be asynchronous.
**Type definition**
```go
func Async[V any](f func() V) func() *AsyncTask[V] {...}
```
**Usage**
```go
package main
import (
"fmt"
"time"
"github.com/sun0day/async"
)
func main() {
a := 1
b := 2
f := func() int {
c := a + b
fmt.Printf("async result=%d\n", c)
return c
}
af := async.Async[int](f)
fmt.Printf("sync start, goroutine=%d\n", runtime.NumGoroutine())
af()
fmt.Printf("sync end, goroutine=%d\n", runtime.NumGoroutine())
time.Sleep(1 * time.Second)
fmt.Printf("async end, goroutine=%d\n", runtime.NumGoroutine())
}
/* stdout
sync start, goroutine=1
sync end, goroutine=2
async result=3
async end, goroutine=1
*/
```
### `async.Await`
Wait `async.AsyncTask` to be done.
**Type definition**
```go
func Await[V any](t *AsyncTask[V]) (V, any) {...}
```
**Usage**
```go
package main
import (
"fmt"
"runtime"
"github.com/sun0day/async"
)
func main() {
a := 1
b := 2
f1 := func() int {
c := a + b
return c
}
f2 := func() int {
panic("f() error")
}
af1 := async.Async[int](f1)
af2 := async.Async[int](f2)
fmt.Printf("sync start, goroutine=%d\n", runtime.NumGoroutine())
value, _ := async.Await[int](af1())
_, err := async.Await[int](af2())
fmt.Printf("af1 result=%d\n", value)
fmt.Printf("af2 error=%s\n", err)
fmt.Printf("sync end, goroutine=%d\n", runtime.NumGoroutine())
}
/* stdout
sync start, goroutine=1
af1 result=3
af2 error=f() error
sync end, goroutine=1
*/
```
### `async.All`
Asynchronously return values(when all `func`s are finished) or error(once one of `func`s throws error).
**Type definition**
```go
func All[V any](fs []func() V) *AsyncTask[[]V] {...}
```
**Usage**
```go
package main
import (
"fmt"
"runtime"
"time"
"github.com/sun0day/async"
)
func main() {
a := 1
b := 2
f1 := func() int {
time.Sleep(1 * time.Second)
c := a + b
return c
}
f2 := func() int {
time.Sleep(2 * time.Second)
c := a * b
return c
}
f3 := func() int {
panic("f3 error")
}
fmt.Printf("sync start, goroutine=%d\n", runtime.NumGoroutine())
values, _ := async.Await[[]int](async.All[int]([]func() int{f1, f2}))
_, err := async.Await[[]int](async.All[int]([]func() int{f1, f2, f3}))
fmt.Printf("all result=%v\n", values)
fmt.Printf("all error=%s\n", err)
fmt.Printf("sync end, goroutine=%d\n", runtime.NumGoroutine())
}
/* stdout
sync start, goroutine=1
all result=[3 2]
all error=f3 error
sync end, goroutine=1
*/
```
### `async.Race`
Asynchronously return value or error of the fisrt finished `func`.
**Type definition**
```go
func Race[V any](fs []func() V) *AsyncTask[V] {...}
```
**Usage**
```go
package main
import (
"fmt"
"runtime"
"time"
"github.com/sun0day/async"
)
func main() {
a := 1
b := 2
f1 := func() int {
time.Sleep(1 * time.Second)
c := a + b
return c
}
f2 := func() int {
time.Sleep(2 * time.Second)
c := a * b
return c
}
fmt.Printf("sync start, goroutine=%d\n", runtime.NumGoroutine())
value, _ := async.Await[int](async.Race[int]([]func() int{f1, f2}))
fmt.Printf("race result=%d\n", value)
fmt.Printf("sync end, goroutine=%d\n", runtime.NumGoroutine())
}
/* stdout
sync start, goroutine=1
race result=3
sync end, goroutine=2
*/
```