I am attempting to make a HTTP call using OkHttpClient. I'm attempting to implement retries on the client in case I see SocketTimeoutExceptions. Here's what I have:
builder.addInterceptor(new Interceptor() {
#Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
// try the request
Response response = null;
int tryCount = 1;
while (tryCount <= MAX_TRY_COUNT) {
try {
response = chain.proceed(request);
break;
} catch (Exception e) {
if (!NetworkUtils.isNetworkAvailable()) {
// if no internet, dont bother retrying request
throw e;
}
if ("Canceled".equalsIgnoreCase(e.getMessage())) {
// Request canceled, do not retry
throw e;
}
if (tryCount >= MAX_TRY_COUNT) {
// max retry count reached, giving up
throw e;
}
try {
// sleep delay * try count (e.g. 1st retry after 3000ms, 2nd after 6000ms, etc.)
Thread.sleep(RETRY_BACKOFF_DELAY * tryCount);
} catch (InterruptedException e1) {
throw new RuntimeException(e1);
}
tryCount++;
}
}
// otherwise just pass the original response on
return response;
}
})
.callTimeout(5000)
.build()
The part which I'm confused about is this - Is the 5000ms timeout for a single exclusive of retries, or is it inclusive of retries?
Nevermind, found the answer here - https://square.github.io/okhttp/4.x/okhttp/okhttp3/-ok-http-client/-builder/call-timeout/
"If the call requires redirects or retries all must complete within one timeout period."
Related
I have a BizTalk Custom Pipeline Component that writes an SFTP file (using SSH.net), triggered by an SFTP (WinSCP) receive location.
The code within the Retry occasionally (around half the time) does not hit either the "Success" nor the logging catch block and no further processing occurs within the Pipeline. I assume that means the thread has been destroyed.
I added the Retry code later to make it try a few times but with the thread being destroyed I don't always get a success or 3 failures.
What could cause this behaviour in BizTalk 2016?
public void Archive(byte[] content,
string archivePath,
string userName,
string password,
string serverAddress,
string sshHostKeyFingerprint)
{
Retry(3, () =>
{
try
{
using (var sftpClient = new SftpClient(serverAddress, userName, password))
{
if (!string.IsNullOrWhiteSpace(sshHostKeyFingerprint))
{
sshHostKeyFingerprint = sshHostKeyFingerprint.Split(' ').Last();
sftpClient.HostKeyReceived += delegate (object sender, HostKeyEventArgs e)
{
if (e.FingerPrint.SequenceEqual(ConvertFingerprintToByteArray(sshHostKeyFingerprint)))
e.CanTrust = true;
else
e.CanTrust = false;
};
}
sftpClient.Connect();
sftpClient.WriteAllBytes(archivePath, content);
sftpClient.Disconnect();
LogInfo($"Success");
}
}
catch (Exception exception)
{
// show the bad path for "No such file" errors
throw new InvalidOperationException($"Failed to create file '{archivePath}'", exception);
}
});
}
private void Retry(int maxAttempts, Action action)
{
int attempt = 1;
while (attempt <= maxAttempts)
{
try
{
action();
break; // success
}
catch (Exception exception)
{
LogWarning($"Attempt {attempt} Error: {exception.ToString()}");
if (attempt == maxAttempts)
throw; // final attempt exception propagated
}
finally
{
attempt++;
}
}
}
I am trying to throttle outgoing http requests using Jersey Client. Since I am running is a Vertx Verticle I created a special RateLimiter class to handle throttling.
My goal is to prevent HTTP calls from being made at a greater rate than 1 per second. the idea is that a submitted callable will run using the single threaded ExecutorService so that I can block that single thread in order to guarantee that these tasks are not handled in a greater rate.
Basically the only public method in this class is "call" :
public <T> Observable<T> call(Callable<Observable<T>> action) {
return Observable.create(subscriber -> {
Observable<Observable<T>> observed =
Observable.from(executor.submit(() -> {
return action.call();
})
).doOnError(throwable -> {
logger.error(throwable);
}
);
observed.subscribe(t -> {
try {
Thread.sleep(1000);
t.subscribe(data -> {
try {
subscriber.onNext(data);
} catch (Throwable e) {
subscriber.onError(e);
}
subscriber.onCompleted();
});
} catch (Exception e) {
logger.error(e);
}
});
});
}
this is my current implementation which uses 1 second sleep no matter how much time has passed since the previous call. initially I tried using a ScheduledExecutorService and calculate the delay time so that I will submit requests exactly at the rate of 1 per second. however, in both cases it often fails to meet the rate restrictions and I get two requests submitted immediately one after the other.
My assumption is that somewhere the requests is being handed to a different executing queue which is being polled by a different thread continuously, so that if for some reason that thread was busy and two requests exist in the queue at the same time, they will be executed sequentially but with no delays.
Any Ideas how to resolve this? maybe a different approach?
I would go with simple Vertx event bus and a queue, from which you poll every second:
public static void main(String[] args) {
Vertx vertx = Vertx.vertx();
vertx.deployVerticle(new DebounceVerticle(), (r) -> {
// Ok, verticle is ready!
// Request to send 10 events in 1 second
for (int i = 0; i < 10; i++) {
vertx.eventBus().publish("call", UUID.randomUUID().toString());
}
});
}
private static class DebounceVerticle extends AbstractVerticle {
HttpClient client;
#Override
public void start() {
client = vertx.createHttpClient();
BlockingQueue<String> queue = new LinkedBlockingQueue<>();
vertx.eventBus().consumer("call", (payload) -> {
String message = (String) payload.body();
queue.add(message);
System.out.println(String.format("I got %s but I don't know when it will be executed", message));
});
vertx.setPeriodic(1000, (l) -> {
String message = queue.poll();
if (message != null) {
System.out.println(String.format("I'm finally sending %s", message));
//Do your client magic
}
});
}
}
Just prepend web service call with guava RateLimiter. Here's an example in RxJava which shows how events every 500ms are throttled to be once per second.
Function<Long, Long> throttlingFunction = new Function<Long, Long>() {
private RateLimiter limiter = RateLimiter.create(1.0);
public Long apply(Long t) throws Exception {
limiter.acquire();
return t;
}
};
Observable.interval(500, TimeUnit.MILLISECONDS)
.map(throttlingFunction)
.subscribe(new Consumer<Long>() {
public void accept(Long t) throws Exception {
System.out.println(t);
}
});
Also in vert.x all the blocking stuff is supposed to be run with the help of executeBlocking.
I started implementing a sample server (in netty) to support 100 continue.
I got some confusion when I go thrugh the RCF2616 section 8.2.3. It says
Upon receiving a request which includes an Expect request-header
field with the "100-continue" expectation, an origin server MUST
either respond with 100 (Continue) status and continue to read
from the input stream, or respond with a final status code. The
origin server MUST NOT wait for the request body before sending
the 100 (Continue) response. If it responds with a final status
code, it MAY close the transport connection or it MAY continue
to read and discard the rest of the request. It MUST NOT
perform the requested method if it returns a final status code.
What does it mean by The origin server MUST NOT wait for the request body before sending the 100 (Continue) response.
Should my server first validate the headers and then send the 100 (continue) status code or Immediately send the 100 status code ?
Please clarify me the actual behavior of a http server to support 100 continue
Currently this is my channelRead
#Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
if (msg instanceof HttpRequest) {
HttpRequest req = (HttpRequest) msg;
request = req;
if (req.getMethod() != HttpMethod.POST) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, METHOD_NOT_ALLOWED);
ctx.write(response).addListener(ChannelFutureListener.CLOSE);
} else {
boolean valid = false;
for (Map.Entry<String, String> header : req.headers()) {
if (header.getKey().equals("my-special-header")) {
valid = true;
break;
}
}
if (!valid) {
FullHttpResponse resp = new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST);
ctx.write(resp).addListener(ChannelFutureListener.CLOSE);
} else {
if (HttpHeaders.is100ContinueExpected(request)) {
ctx.write(new DefaultFullHttpResponse(HTTP_1_1, CONTINUE));
}
}
}
} else if (msg instanceof LastHttpContent && msg != LastHttpContent.EMPTY_LAST_CONTENT) {
DefaultLastHttpContent content = (DefaultLastHttpContent) msg;
System.out.println("content read");
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, content.content());
response.headers().set(CONTENT_TYPE, "text/plain");
response.headers().set(CONTENT_LENGTH, response.content().readableBytes());
boolean keepAlive =HttpHeaders.isKeepAlive(request);
if (!keepAlive) {
ctx.write(response).addListener(ChannelFutureListener.CLOSE);
} else {
response.headers().set(CONNECTION, Values.KEEP_ALIVE);
ctx.write(response);
}
}
}
I think "MUST NOT wait for the request body" is pretty clear. The body does not include thee headers, so I'm not sure where your confusion comes from...
I am trying to reuse a Jersey2(Jersey 2.16) Client for async invocation. However after 2 requests, I see that the threads going into a waiting state, waiting on a lock. Since client creation is an expensive operation, I am trying to reuse the client in the async calls. The issue occurs only with ApacheConnectorProvider as the connector class. I want to use ApacheConnectorProvider, as I need to use a proxy and set SSL properties and I want to use PoolingHttpClientConnectionManager.
The sample code is given below:
public class Example {
Integer eventId = 0;
private ClientConfig getClientConfig()
{
ClientConfig clientConfig = new ClientConfig();
ApacheConnectorProvider provider = new ApacheConnectorProvider();
clientConfig.property(ClientProperties.REQUEST_ENTITY_PROCESSING,RequestEntityProcessing.BUFFERED);
clientConfig.connectorProvider(provider);
return clientConfig;
}
private Client createClient()
{
Client client = ClientBuilder.newClient(getClientConfig());
return client;
}
public void testAsyncCall()
{
Client client = createClient();
System.out.println("Testing a new Async call on thread " + Thread.currentThread().getId());
JSONObject jsonObject = new JSONObject();
jsonObject.put("value", eventId++);
invoker(client, "http://requestb.in/nn0sffnn" , jsonObject);
invoker(client, "http://requestb.in/nn0sffnn" , jsonObject);
invoker(client, "http://requestb.in/nn0sffnn" , jsonObject);
client.close();
}
private void invoker(Client client, String URI, JSONObject jsonObject)
{
final Future<Response> responseFuture = client.target(URI)
.request()
.async()
.post(Entity.entity(jsonObject.toJSONString(), MediaType.TEXT_PLAIN));
try {
Response r = responseFuture.get();
System.out.println("Response is on URI " + URI + " : " + r.getStatus());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String args[])
{
Example client1 = new Example();
client1.testAsyncCall();
return;
}
}
The response I see is:
Testing a new Async call on thread 1
Response is on URI http://requestb.in/nn0sffnn : 200
Response is on URI http://requestb.in/nn0sffnn : 200
On looking at the thread stack, I see the following trace:
"jersey-client-async-executor-0" prio=6 tid=0x043a4c00 nid=0x56f0 waiting on condition [0x03e5f000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x238ee148> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2043)
at org.apache.http.pool.PoolEntryFuture.await(PoolEntryFuture.java:133)
at org.apache.http.pool.AbstractConnPool.getPoolEntryBlocking(AbstractConnPool.java:282)
at org.apache.http.pool.AbstractConnPool.access$000(AbstractConnPool.java:64)
at org.apache.http.pool.AbstractConnPool$2.getPoolEntry(AbstractConnPool.java:177)
at org.apache.http.pool.AbstractConnPool$2.getPoolEntry(AbstractConnPool.java:170)
Can someone give me a suggestion as to how to reuse Client objects for async requests and may be how to get over this issue as well.
i am implementing a jax-rs service with RestEasy on JBoss AS 7.1.2 an i would like to use asynchronous HTTP processsing as described here: http://docs.jboss.org/resteasy/docs/1.0.0.GA/userguide/html/Asynchronous_HTTP_Request_Processing.html
For thr AsynchronousResponse I define a timeout of 10 seconds. When this period expires, the request is responded with a 200 OK and an empty body. I would like to modify this behaviour so i need to be notified about the timeout event.
In my solution, I would like to handle the timeout event in a NotificationManager object, which keeps the AsycnhronousResponse for the time being. Please see the code below for details.
So far, i could not figure out how to do that. Does anyone have more experience with the RestEasy Asynchronous HTTP processing?
#POST
#Path("/blabla")
#Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
#Consumes({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
public void subscribeLongPolling (
final #Suspend(10000) AsynchronousResponse response,
JAXBElement<LongPollingRequestParameters> rqParam,
#Context HttpServletRequest req) throws Exception {
//do some stuff with req
Thread t = new Thread("ThreadSubscribeTo:" + channelID)
{
#Override
public void run() {
//hand over to Notification Manager to return notifications in case some exist
try {
NotificationManager nm = new NotificationManager();
nm.setAsyncResponseObject(response);
logger.info("Response object registered in NotificationManager");
}catch (Exception e){
e.printStackTrace();
}
}
};
t.start();
logger.info("Releasing Thread");
}
public class NotificationManager {
private AsynchronousResponse response;
private NotificationList nList;
public synchronized void setAsyncResponseObject(AsynchronousResponse response) {
this.response = response;
if (nList.getAny().size() > 0) {
logger.info("Stored notification send to web client: " + nList.getAny().get(0).toString());
sendNotification(nList.getAny().remove(0));
}
}
public synchronized void sendNotification(Object message){
if (response != null){
logger.info("Response object found. Send notification immediately: " + message.toString());
Response responseObject = Response.ok(message, MediaType.APPLICATION_XML).build();
response.setResponse(responseObject);
response = null;
}else{
logger.info("Response object not found notification will be stored");
addNotification(message);
}
}
}
Thanks in advance,
Alex