Async HTTP Request Connection Timeout Not Work Correctly #610
Comments
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After going through public class Main {
public static void main(String[] args) throws IOReactorException {
RequestConfig requestConfig = RequestConfig.custom()
.setConnectTimeout(1)
.setSocketTimeout(500)
.setRedirectsEnabled(true)
.build();
HttpUriRequest httpUriRequest = new HttpGet("http://255.255.33.44:8001/");
httpUriRequest.addHeader("Connection", "close");
IOReactorConfig reactorConfig = IOReactorConfig.custom()
// .setConnectTimeout(500)
// .setSoTimeout(500)
.setShutdownGracePeriod(1)
.build();
DefaultConnectingIOReactor defaultConnectingIOReactor = new DefaultConnectingIOReactor(reactorConfig);
Registry registry = RegistryBuilder.create()
.register("http", NoopIOSessionStrategy.INSTANCE)
.build();
PoolingNHttpClientConnectionManager connectionManager = new PoolingNHttpClientConnectionManager(defaultConnectingIOReactor, registry);
HttpClientContext context = new HttpClientContext();
context.setRequestConfig(requestConfig);
connectionManager.setMaxTotal(1);
CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setConnectionManager(connectionManager)
.build();
client.start();
long startTime = System.nanoTime();
client.execute(httpUriRequest, context, new FutureCallback<HttpResponse>() {
@Override
public void completed(HttpResponse httpResponse) {
StatusLine statusLine = httpResponse.getStatusLine();
int statusCode = statusLine.getStatusCode();
long stopTime = System.nanoTime();
System.out.print("=====completed, timeElapsed: ");
System.out.print(TimeUnit.MILLISECONDS.convert(System.nanoTime() - startTime, TimeUnit.NANOSECONDS));
System.out.println(" ms");
System.out.print(statusCode);
}
@Override
public void failed(Exception e) {
System.out.print("=====failed, timeElapsed: ");
System.out.print(TimeUnit.MILLISECONDS.convert(System.nanoTime() - startTime, TimeUnit.NANOSECONDS));
System.out.println(" ms");
System.out.print("=====error msg: " + e.getMessage());
try {
connectionManager.shutdown();
} catch (IOException ex) {
ex.printStackTrace();
}
}
@Override
public void cancelled() {
httpUriRequest.abort();
try {
connectionManager.shutdown();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
}When So it seems like code execute time is about ~1000ms, it takes at least 1 second from the start of the request to fail if the connect timeout is less than ~1000ms. But synchronous requests do not have such high latency (interval from request to failure), I guess because asynchronous requests require a lot of setup code to be processed, including the creation of connection pools, so the creation of asynchronous request clients is time-consuming expensively. |
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After some research, I figure out a way to solve my problem which used Here is the main code(gist): ;; lein repl
(ns test (:require [clojure.core.async :as async]
[clj-http.client :as client]))
;; define test data
(def urls ["http://www.google.com" "http://www.google1.com" "http://255.255.33.44:8001/"])
;; use async/go to build a async http client
(defn fetch-async
[url]
(let [ret (async/promise-chan)]
(async/go
(try
(let [res (client/get url {:socket-timeout 500
:connection-timeout 500})]
(async/put! ret {:result :success :msg (:status res)}))
(catch Exception e (async/put! ret {:result :error :msg (.getMessage e)}))))
ret))
;; use async/go to build a async http client but disable apache http client retry feature
(defn fetch-async-without-retry
[url]
(let [ret (async/promise-chan)]
(async/go
(try
(let [res (client/get url {:socket-timeout 500
:connection-timeout 1000
:retry-handler (fn [ex try-count http-context]
(if (> try-count 0) false true))})]
(async/put! ret {:result :success :msg (:status res)}))
(catch Exception e (async/put! ret {:result :error :msg (.getMessage e)}))))
ret))
;; test fetach a domain url
(time (async/<!! (fetch-async "http://www.google1.com")))
;; test fetach an ip url
(time (async/<!! (fetch-async "http://255.255.33.44:8001/")))
;; block main thread to get all response data
(let [res-promise (map #(fetch-async %) urls)]
(map #(async/<!! %) res-promise))
;; metric the execute time
(let [res-promise (map #(fetch-async %) urls)]
(map #(time (async/<!! %)) res-promise))
(time (let [res-promise (map #(fetch-async %) urls)]
(map #(async/<!! %) res-promise)))
(let [res-promise (map #(fetch-async %) urls)]
(time (map #(async/<!! %) res-promise)))and the result is good. From the above test results, we can see that after the first request takes 500ms (which is the connect-timeout we set), the other requests are executed asynchronously and the total time is almost 500ms at the end. Moreover, the async/go process is very lightweight and does not consume as many resources and execution time as a thread does. |
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Note that here: (async/go
(try
(let [res (client/get url {:socket-timeout 500
:connection-timeout 1000
:retry-handler (fn [ex try-count http-context]
(if (> try-count 0) false true))})]
(async/put! ret {:result :success :msg (:status res)}))****you're doing a blocking call (
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Backgroud
When using clj-http async requests some do not exist URL and set the connection timeout, but the connection timeout is delayed 2-3 seconds.
Test
The test version is
3.12.2, and the test way islein repl, my lein config in~/.lein/profiles.clj:{ :user { :plugins [[lein-midje "3.2.1"] [lein-shell "0.5.0"]] :dependencies [[org.clojure/clojure "1.10.3"] [rhizome "0.2.9"] [org.clojure/core.match "1.0.0"] [buddy/buddy-sign "3.1.0"] [clj-http "3.12.2"] [environ "1.1.0"] [cheshire "5.10.0"] [instaparse "1.4.10"]] } }and then, run
lein replto go to the repl environment.Example 1
Expectation
Cause the URL does not exist, so the time will be conn-timeout which is ~1ms.
Test Result
"Elapsed time: 3019.764098 msecs"
{:error "Timeout connecting to [/255.255.33.44:8001]"}
Example 2
Expectation
Cause the URL does not exist, so the time will be conn-timeout which is ~5000ms.
Test Result
"Elapsed time: 7203.527474 msecs"
{:error "Timeout connecting to [/255.255.33.44:8001]"}
Example 3
Expectation
Cause the URL does not exist, so the time will be conn-timeout which is ~5000ms.
Test Result
"Elapsed time: 5010.862797 msecs"
"caught exception: connect timed out"
Example 4
Expectation
Cause the URL does not exist, so the time will be conn-timeout which is ~1ms.
Test Result
"Elapsed time: 8.649284 msecs"
"caught exception: connect timed out"
Bug
As in the above test, Example 1 and Example 2 are test requests in
asyncmode, and Example 3 and Example 4 are control requests insyncmode. Thesyncmode request is as expected, but the async mode request is 2-3 seconds longer than the set conn-timeout.The text was updated successfully, but these errors were encountered: