通过goroutine异步发布到google pub sub [英] Publishing to google pub sub asynchronously through goroutine
问题描述
我正在尝试通过goroutine将消息异步推送到google pub-sub,但是我遇到了以下错误
panic: not an App Engine context
我正在使用mux并有一个api处理程序
I'm trying to push the message to google pub-sub asynchronously through goroutine but I'm facing below error
panic: not an App Engine context
I'm using mux and have an api handler
n = 1百万
func apihandler(w http.ResponseWriter, r *http.Request) {
go createuniquecodes(n)
return "request running in background"
}
func createuniquecodes(n) {
c := make(chan string)
go createuniquecodes(c, n)
for val := range c {
publishtopubsub(val)
}
}
func createuniquecodes(n) {
for i := 0; i < n; i++ {
uniquecode := some random string
// publish to channel and pubsub
c <- uniquecode
}
close(c)
}
func publishuq(msg string) error {
ctx := context.Background()
client, err := pubsub.NewClient(ctx, projectId)
if err != nil {
log.Fatalf("Could not create pubsub Client: %v", err)
}
t := client.Topic(topicName)
result := t.Publish(ctx, &pubsub.Message{
Data: []byte(msg),
})
id, err := result.Get(ctx)
if err != nil {
return err
}
fmt.Printf("Published a message; msg ID: %v\n", id)
return nil
}
请注意,我需要生成500万个唯一代码, 由于我是异步进行的,因此如何在go例程中定义上下文
Please note that I need to generate 5 million unique codes, How will I define a context in go routine since I'm doing everything asynchronously
推荐答案
我假设您使用的是App Engine标准(非灵活)环境.请注意,请求处理程序(在您的情况下为apihandler
)在有限的时间内生成并返回对请求的响应,
I assume you're using the App Engine standard (not flexible) environment. Please note that a "request handler (apihandler
in your case) has a limited amount of time to generate and return a response to a request, typically around 60 seconds. Once the deadline has been reached, the request handler is interrupted".
您正在尝试在调用go createuniquecodes(n)
然后在ctx := context.Background()
时中断"请求,这是not an App Engine context
感到恐慌的原因.从技术上讲,您可以使用 NewContext(req * http.Request)从原始上下文中获取有效上下文,但是同样,请求超时之前只有60秒.
You're trying to "break out" of the request when calling go createuniquecodes(n)
and then ctx := context.Background()
down the line is what panics with not an App Engine context
. You could technically use NewContext(req *http.Request) to derive a valid context from the original context, but again, you'd only have 60s before your request times out.
请查看任务队列,因为它们让应用程序在用户请求之外异步执行工作(称为任务)."
Please have a look at TaskQueues, as they " let applications perform work, called tasks, asynchronously outside of a user request."
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