I am having a scenario where I am using consumer template to receive file from a endpoint. The Endpoint could be either File System or FTP site. Currently I am using only File System with following endpoint URL:
file://D:/metamodel/Seach.json?noop=true&idempotent=false
On every hit to following code:
Exchange exchange = consumerTemplate.receive(endPointURI, timeout);
if (exchange != null) {
String body = exchange.getIn().getBody(String.class);
consumerTemplate.doneUoW(exchange);
return body;
}
It creating a new Camel context thread and after some hits it giving error as
java.util.concurrent.RejectedExecutionException: PollingConsumer on Endpoint[file://D:/metamodel/Seach.json?noop=true&idempotent=false] is not started, but in state:Stopped
I am not sure why this is happening and its sporadic in nature.
Any suggestion on this would do great help.
Related
I am using apache camel 3.8 and trying to make a simple tcp server that sends the request message back to the client (the client I am using is PacketSender).
The problem is, if the process() method takes too long an empty response is sent back by netty in the background after 15ms, even if the process() is still in the Thread.sleep hold.
If I do not let the method (thread) sleep, the response is sent with the received content immediatly.
How can I manage it, that netty is waiting until I finished my process and send the response I set in the exchange message body?
Here is the route I am using:
fromF("netty:tcp://%s:%d?sync=true&synchronous=true&disconnectOnNoReply=false&connectTimeout=100000", host, receivePort)
.bean(HL7Request.class, "process", BeanScope.Request);
The bean process method looks like this, for simulation purpose of my long taking process I used a Thread.sleep:
public void process(Exchange exchange) throws Exception {
try {
CamelContext context = exchange.getContext();
exchange.setException(null);
Thread.sleep(5000); // <-- Here the method stopps for 5 seconds but the response is sent by netty anyway
String content = exchange.getMessage().getBody(String.class);
System.out.println(content);
}
catch (Exception e) {
exchange.setException(e);
}
}
PacketSender receives an empty response
Thank you.
Regards,
Florian
I think it was an issue with PacketSender Software. It perfectly works using command line telnet.
More details to the bug
I want to run a processor upon file appearance in a directory. My file url is like this:
file:{{file.root}}in?include=.*\.csv&charset=windows-1251&move=../out/done
A procedure that associates an url with a processor is like this:
MessageProcessor getOrCreateConsumer(CamelContext context, String uri) {
Endpoint endpoint = context.getEndpoint(uri);
endpoint.setCamelContext(context); // added this out of desperation, doesn't help
processor = new MessageProcessor();
try {
Consumer consumer = endpoint.createConsumer(processor);
endpoint.start(); // do we need this at all? works the same without it
consumer.start();
} catch (Exception e) {
throw new RuntimeException(e);
}
return processor;
}
}
MessageProcessor is a processor that does some things to an exchange.
Everything seems to work except the file doesn't get moved to the ../out/done directory. While debugging I can't get when the endpoint is configured to provide the file message exchange with this post operation.
I think I am missing some magic call that is normally invoked by a RouteBuilder and that will fully configure the file endpoint. Can you please help me out?
I am trying to implement more advanced Apache Camel error handling:
in case if there are too many pending retries then stop processing at all and log all collected exceptions somewhere.
First part (stop on too many retries) is already implemented by following helper method, that gets size of retry queue and I just stop context if queue is over some limit:
static Long getToRetryTaskCount(CamelContext context) {
Long retryTaskCount = null;
ScheduledExecutorService errorHandlerExecutor = context.getErrorHandlerExecutorService();
if (errorHandlerExecutor instanceof SizedScheduledExecutorService)
{
SizedScheduledExecutorService svc = (SizedScheduledExecutorService) errorHandlerExecutor;
ScheduledThreadPoolExecutor executor = svc.getScheduledThreadPoolExecutor();
BlockingQueue<Runnable> queue = executor.getQueue();
retryTaskCount = (long) queue.size();
}
return retryTaskCount;
}
But this code smells to me and I don't like it and also I don't see here any way to collect the exceptions caused all this retries.
There is also a new control bus component in camel 2.11 which could do what you want (source)
template.sendBody("controlbus:route?routeId=foo&action=stop", null);
I wouldn't try to shutdown the CamelContext, just the route in question...that way the rest of your app can still function, you can get route stats and view/move messages to alternate queues, etc.
see https://camel.apache.org/how-can-i-stop-a-route-from-a-route.html
Ok, I understand that maybe very stupid question, but i never did it before, so i ask this question. How can i download file (let's say, from the internet) using Thread class?
What do you mean with "using Thread class"? I guess you want to download a file threaded so it does not block your UI or some other part of your program.
Ill assume that your using C++ and WINAPI.
First create a thread. This tutorial provides good information about WIN32 threads.
This thread will be responsible for downloading the file. To do this you simply connect to the webserver on port 80 and send a HTTP GET request for the file you want. It could look similar to this (note the newline characters):
GET /path/to/your/file.jpg HTTP/1.1\r\n
Host: www.host.com\r\n
Connection: close\r\n
\r\n
\r\n
The server will then answer with a HTTP response containing the file with a preceding header. Parse this header and read the contents.
More information on HTTP can be found here.
If would suggest that you do not use threads for downloading files. It's better to use asynchronous constructs that are more targeted towards I/O, since they will incur a lower overhead than threads. I don't know what version of the .NET Framework you are working with, but in 4.5, something like this should work:
private static Task DownloadFileAsync(string uri, string localPath)
{
// Get the http request
HttpWebRequest webRequest = WebRequest.CreateHttp(uri);
// Get the http response asynchronously
return webRequest.GetResponseAsync()
.ContinueWith(task =>
{
// When the GetResponseAsync task is finished, we will come
// into this contiuation (which is an anonymous method).
// Check if the GetResponseAsync task failed.
if (task.IsFaulted)
{
Console.WriteLine(task.Exception);
return null;
}
// Get the web response.
WebResponse response = task.Result;
// Open a file stream for the local file.
FileStream localStream = File.OpenWrite(localPath);
// Copy the contents from the response stream to the
// local file stream asynchronously.
return response.GetResponseStream().CopyToAsync(localStream)
.ContinueWith(streamTask =>
{
// When the CopyToAsync task is finished, we come
// to this continuation (which is also an anonymous
// method).
// Flush and dispose the local file stream. There
// is a FlushAsync method that will flush
// asychronously, returning yet another task, but
// for the sake of brevity I use the synchronous
// method here.
localStream.Flush();
localStream.Dispose();
// Don't forget to check if the previous task
// failed or not.
// All Task exceptions must be observed.
if (streamTask.IsFaulted)
{
Console.WriteLine(streamTask.Exception);
}
});
// since we end up with a task returning a task we should
// call Unwrap to return a single task representing the
// entire operation
}).Unwrap();
}
You would want to elaborate a bit on the error handling. What this code does is in short:
See the code comments for more detailed explanations of how it works.
In my java code, I am processing huge amount of data. So I moved the code as servlet to Cron Job of App Engine. Some days it works fine. After the amount of the data increases, the cron job is not working and shows the following error message.
2012-09-26 04:18:40.627
'ServletName' 'MethodName': Inside SQLExceptionjava.sql.SQLRecoverableException:
Connection is already in use.
I 2012-09-26 04:18:40.741
This request caused a new process to be started for your application, and thus caused
your application code to be loaded for the first time. This request may thus take
longer and use more CPU than a typical request for your application.
W 2012-09-26 04:18:40.741
A problem was encountered with the process that handled this request, causing it to
exit. This is likely to cause a new process to be used for the next request to your
application. If you see this message frequently, you may be throwing exceptions during
the initialization of your application. (Error code 104)
How to handle this problem?
This exception is typical when a single connection is shared between multiple threads. This will in turn happen when your code does not follow the standard JDBC idiom of acquiring and closing the DB resources in the shortest possible scope in the very same try-finally block like so:
public Entity find(Long id) throws SQLException {
Connection connection = null;
// ...
try {
connection = dataSource.getConnection();
// ...
} finally {
// ...
if (connection != null) try { connection.close(); } catch (SQLException ignore) {}
}
return entity;
}
Your comment on the question,
#TejasArjun i used connection pooling with servlet Init() method.
doesn't give me the impression that you're doing it the right way. This suggests that you're obtaining a DB connection in servlet's init() method and reusing the same one across all HTTP requests in all HTTP sessions. This is absolutely not right. A servlet instance is created/initialized only once during webapp's startup and reused throughout the entire remaining of the application's lifetime. This at least confirms the exception you're facing.
Just rewrite your JDBC code according the standard try-finally idiom as demonstrated above and you should be all set.
See also:
Is it safe to use a static java.sql.Connection instance in a multithreaded system?