51 lines
1.3 KiB
Go
51 lines
1.3 KiB
Go
package queueing
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import (
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"net/http"
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"time"
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"gitlab.com/gitlab-org/gitlab/workhorse/internal/helper"
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)
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const (
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DefaultTimeout = 30 * time.Second
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httpStatusTooManyRequests = 429
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)
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// QueueRequests creates a new request queue
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// name specifies the name of queue, used to label Prometheus metrics
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// Don't call QueueRequests twice with the same name argument!
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// h specifies a http.Handler which will handle the queue requests
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// limit specifies number of requests run concurrently
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// queueLimit specifies maximum number of requests that can be queued
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// queueTimeout specifies the time limit of storing the request in the queue
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func QueueRequests(name string, h http.Handler, limit, queueLimit uint, queueTimeout time.Duration) http.Handler {
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if limit == 0 {
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return h
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}
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if queueTimeout == 0 {
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queueTimeout = DefaultTimeout
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}
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queue := newQueue(name, limit, queueLimit, queueTimeout)
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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err := queue.Acquire()
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switch err {
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case nil:
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defer queue.Release()
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h.ServeHTTP(w, r)
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case ErrTooManyRequests:
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http.Error(w, "Too Many Requests", httpStatusTooManyRequests)
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case ErrQueueingTimedout:
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http.Error(w, "Service Unavailable", http.StatusServiceUnavailable)
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default:
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helper.Fail500(w, r, err)
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}
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})
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}
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