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package queueing
import (
"fmt"
"net/http"
"net/http/httptest"
"testing"
"time"
"github.com/prometheus/client_golang/prometheus"
)
var httpHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "OK")
})
func pausedHttpHandler(pauseCh chan struct{}) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
<-pauseCh
fmt.Fprintln(w, "OK")
})
}
func TestNormalRequestProcessing(t *testing.T) {
w := httptest.NewRecorder()
h := QueueRequests("Normal request processing", httpHandler, 1, 1, time.Second, prometheus.NewRegistry())
h.ServeHTTP(w, nil)
if w.Code != 200 {
t.Fatal("QueueRequests should process request")
}
}
// testSlowRequestProcessing creates a new queue,
// then it runs a number of requests that are going through queue,
// we return the response of first finished request,
// where status of request can be 200, 429 or 503
func testSlowRequestProcessing(name string, count int, limit, queueLimit uint, queueTimeout time.Duration) *httptest.ResponseRecorder {
pauseCh := make(chan struct{})
defer close(pauseCh)
handler := QueueRequests("Slow request processing: "+name, pausedHttpHandler(pauseCh), limit, queueLimit, queueTimeout, prometheus.NewRegistry())
respCh := make(chan *httptest.ResponseRecorder, count)
// queue requests to use up the queue
for i := 0; i < count; i++ {
go func() {
w := httptest.NewRecorder()
handler.ServeHTTP(w, nil)
respCh <- w
}()
}
// dequeue first request
return <-respCh
}
// TestQueueingTimeout performs 2 requests
// the queue limit and length is 1,
// the second request gets timed-out
func TestQueueingTimeout(t *testing.T) {
w := testSlowRequestProcessing("timeout", 2, 1, 1, time.Microsecond)
if w.Code != 503 {
t.Fatal("QueueRequests should timeout queued request")
}
}
// TestQueueingTooManyRequests performs 3 requests
// the queue limit and length is 1,
// so the third request has to be rejected with 429
func TestQueueingTooManyRequests(t *testing.T) {
w := testSlowRequestProcessing("too many requests", 3, 1, 1, time.Minute)
if w.Code != 429 {
t.Fatal("QueueRequests should return immediately and return too many requests")
}
}
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