README
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go-common/errgroup
提供带recover的errgroup，err中包含详细堆栈信息
Documentation
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Overview ¶
Package errgroup provides synchronization, error propagation, and Context cancelation for groups of goroutines working on subtasks of a common task.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Group ¶
type Group struct {
// contains filtered or unexported fields
}
A Group is a collection of goroutines working on subtasks that are part of the same overall task.
A zero Group is valid and does not cancel on error.
Example (Ctx) ¶
g, ctx := WithContext(context.Background())
g.Go(func() error {
return fakeRunTask(ctx)
})
g.Go(func() error {
return fakeRunTask(ctx)
})
if err := g.Wait(); err != nil {
// handle err
}
Output:
Example (Group) ¶
g := Group{}
g.Go(func() error {
return fakeRunTask(context.Background())
})
g.Go(func() error {
return fakeRunTask(context.Background())
})
if err := g.Wait(); err != nil {
// handle err
}
Output:
Example (JustErrors) ¶
JustErrors illustrates the use of a Group in place of a sync.WaitGroup to simplify goroutine counting and error handling. This example is derived from the sync.WaitGroup example at https://golang.org/pkg/sync/#example_WaitGroup.
var g Group
var urls = []string{
"http://www.golang.org/",
"http://www.google.com/",
"http://www.somestupidname.com/",
}
for _, url := range urls {
// Launch a goroutine to fetch the URL.
url := url // https://golang.org/doc/faq#closures_and_goroutines
g.Go(func() error {
// Fetch the URL.
resp, err := http.Get(url)
if err == nil {
resp.Body.Close()
}
return err
})
}
// Wait for all HTTP fetches to complete.
if err := g.Wait(); err == nil {
fmt.Println("Successfully fetched all URLs.")
}
Output:
Example (Maxproc) ¶
g := Group{}
// set max concurrency
g.GOMAXPROCS(2)
g.Go(func() error {
return fakeRunTask(context.Background())
})
g.Go(func() error {
return fakeRunTask(context.Background())
})
if err := g.Wait(); err != nil {
// handle err
}
Output:
Example (Parallel) ¶
Parallel illustrates the use of a Group for synchronizing a simple parallel task: the "Google Search 2.0" function from https://talks.golang.org/2012/concurrency.slide#46, augmented with a Context and error-handling.
Google := func(ctx context.Context, query string) ([]Result, error) {
g, ctx := WithContext(ctx)
searches := []Search{Web, Image, Video}
results := make([]Result, len(searches))
for i, search := range searches {
i, search := i, search // https://golang.org/doc/faq#closures_and_goroutines
g.Go(func() error {
result, err := search(ctx, query)
if err == nil {
results[i] = result
}
return err
})
}
if err := g.Wait(); err != nil {
return nil, err
}
return results, nil
}
results, err := Google(context.Background(), "golang")
if err != nil {
fmt.Fprintln(os.Stderr, err)
return
}
for _, result := range results {
fmt.Println(result)
}
Output: web result for "golang" image result for "golang" video result for "golang"
Example (Waitgroup) ¶
var wg sync.WaitGroup
wg.Add(2)
go func() {
// do something
wg.Done()
}()
go func() {
// do something
wg.Done()
}()
wg.Wait()
Output:
func WithContext ¶
WithContext returns a new Group and an associated Context derived from ctx.
The derived Context is canceled the first time a function passed to Go returns a non-nil error or the first time Wait returns, whichever occurs first.
Source Files