I am working on setting up a REST Client using jax-rs 2 client API.
In the api doc it says "Clients are heavy-weight objects that manage the client-side communication infrastructure. Initialization as well as disposal of a Client instance may be a rather expensive operation. It is therefore advised to construct only a small number of Client instances in the application." (https://docs.oracle.com/javaee/7/api/javax/ws/rs/client/Client.html). As per this statement it sounds like Client is not thread-safe and i should not be using single Client instance for all requests.
I am using CXF implementation, so far i didn't find a way to set up pool for Client objects.
If anyone has any information reg this could you please share.
Thanks in advance.
By default, CXF uses a transport based on the in-JDK HttpURLConnection object to perform HTTP requests.
Connection pooling is performed allowing persistent connections to reuse the underlying socket connection for multiple http requests.
Set these system properties to configure the pool(default values)
http.keepalive=true
http.maxConnections=5
Increment the value of http.maxConnections to set the maximum number of idle connections that will be simultaneously kept alive, per destination. See in this link the complete list of properties properties.html
In this post are explained some detail how it works
Java HttpURLConnection and pooling
Note also that the default JAX-RS client is not thread-safe by default. Check the limitations for proper use here
When you need many requests executed simultaneosly CXF can also use the asynchronous apache HttpAsyncClient. Ser details here
http://cxf.apache.org/docs/asynchronous-client-http-transport.html
Related
Background : I am using spring boot with embedded jetty. My app calls bunch of rest apis. For calling these rest apis I use spring rest template.
Question: Is Spring rest template any good at high concurrency? Searching on the web search suggests moving to reactive but still there are apps which are written in blocking way and need to continue that way. Question is what alternate is there or what can be done to make rest template more responsive under heavy load. PoolingHttpClientConnectionManager improves things a bit but essentially still not at par with is required.
There are suggestions to move to rest easy and other http clients but no slid reasoning behind it. End of the day, they all make pool of connections and essentially works the same. Please note, reactive is not an option yet. This question is very specific to traditional blocking rest calls. Any suggestions in optimizing connection pooling or using rest template right will be of great help.
RestTemplate does not do an actual rest call by itself, its just a "wrapper" - a convenient API.
Now when it comes to connection pooling, by default it doesn't use any kind of pooling and just opens URL connections available in Java anyway. No third-parties are required, but performance is not so good.
You can configure rest template to use, say, OkHttp Client under the hood. See here for different ways to work with different clients. The interesting part is that its possible to configure connection pools there and achieve a better performance.
So you should really check what exactly the expected performance is and configure the connection pool accordingly.
Now one more thing about Reactive stuff - it won't give you a performance gain, however it will allow to serve better multiple concurrent requests by reusing resources more efficiently. However if you'll measure how long it takes to perform one single request - its not expected to be performed faster.
In other words you should consider the transition to reactive stack if the application has too many concurrent requests that it can't serve, but not if you want to process every single request faster.
Spring RestTemplate is used to write application level code. It obtains the HTTP connection from ClientHttpRequestFactory implementation which is what glues low-level HTTP client library to Spring e.g. HttpComponentsClientHttpRequestFactory for Apache HTTP Client.
Bottom line, in most cases you have to tune the underlying low-level HTTP client library and not RestTemplate when you are tuning outgoing requests to external APIs.
You are confusing a lot of concepts in your question. Try understanding what is Reactive programming, HTTP, HTTP pipelining, and TCP/IP before you start tuning anything. Otherwise you won't find where is your code's bottleneck and you will end up tuning wrong part of the software stack.
I have a app server that runs multiple camel routes that are reading messages from a JMS Queue, each route runs with different selectors.
We have an app server for each group of clients. So at the end there are multiple connections created to the queue. And that seems to be affecting the read and write performance on the queue.
I tried to use a connection pool, (by the way i am using WMQ), the closest I got is to use spring's CachingConnectionFactory (as described in this post how to configure (spring) JMS connection Pool for WMQ).
I was hoping that the number of connections will reduce from each app server, but that did not happen. Even though i set the size to 5 on the CCFactory, i see 10 connections created to the queue. According to the documentation on CCFactory, explicit closing of the connections is required. Is it possible or does it even make sense to close the connection that is used by a camel route that is reading from a queue? Or is there a way to tell camel routes to share the connections? I thought the use of connection pool and factory will do that, but i don't see that from happening.
Can I achieve what I want to achieve?
Thanks in advance.
what you can do is have only one route reading from the queue instead of many, and then use some camel conditional logic to redirect the message to the correct processing route via direct endpoints, see also this example.
This way there would only one consumer for the queue, instead of multiple consumers each running it's own selector.
I have a bunch of web services servers (around 200) running on the same machine which expose the same service on different ports.
I have a client which perform tasks which include calling the service on different servers.
Something like:
while (true) {
task = readTask();
runHelloService(task.serverAddress)
}
I was wondering what is the best way to generate the HelloService client proxy.
Can I generate one and replace the target address before each call?
Should i generate a client per server (which means 200 client proxies) and use the relevant one?
I will probably want to run the above loop concurrently on several threads.
Currently I have only one proxy which is generated by spring and cxf with the jaxws:client declaration.
This is an interesting use case. I believe that changing the endpoint whilst sharing the proxy amongst multiple threads will not work. There is a one-to-one relationship between a client proxy and a conduit definition. Changes to a conduit are explicitly not thread safe.
I recommend eschewing Spring configuration altogether to create client proxies and instead use programmatic construction of the 200 client proxies.
See also Custom CXF Transport - Simplified Client Workflow.
From EJB transaction I am calling remote site using SOAP. Remote server is not responding. I got transaction time-out. But I want to get time-out from remote call.
How can I set time-out for SOAP request globally?
How can I set time-out for SOAP request for particular call?
You should be able to configure this using a Policy Set. See the link below for IBM's documentation on the topic.
http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/index.jsp?topic=%2Fcom.ibm.websphere.nd.doc%2Fae%2Frwbs_jaxwstimeouts.html
To globally set timeout, you may use HTTP transport custom properties for web services applications. The timeout you're looking for here is timeout. This is by default 300 seconds (which is more than global transaction timeout default value, which is 120 seconds, hence you receive a transaction time-out).
If you are using JAX-RPC, make sure you are at a patch level containing fix for PM60752 (6.1.0.45, 7.0.0.25, 8.0.0.5 and 8.5.0.1).
As indicated at Nick's answer, you have alternative methods to configure timeouts if you are using the newer JAX-WS stack.
When using JAX-RPC you may set timeout for a particular call endpoint as explained in article Setting the timeout value for a JAX-RPC Web Service client. For JAX-WS you may use bindings or go for one of the solutions at How to Set Timeout for JAX-WS WebService Call.
One thing to keep in mind when configuring timeouts for web services is that web service transport depends on HTTP transport (assuming SOAP over HTTP), and in turn that depends on TCP transport, all of which are configurable for various timeouts. The relations between these layers and solutions to common problems are outlined at Common Timeouts effecting Web Services, HTTP and SOAP clients article.
Hi there i am wondering if i create a webapp that uses Spring AMQP. Is that single webapp 1 AMQP client? Or is every request made by a user that results into an AMQP call a client, so potentially x numbers of clients?
I don't know AMQP much, but I suspect it has the same terminology as jms. In that sense your application is probably pooling connections to AMQP broker for better performance. Each connection in a pool is treated as a separate client (competing consumer).
Thus each request is not really creating a new connection (client), but your application isn't a single client as well. In fact, when your application tries to access AMQP broker, it picks any connection from the pool and puts it back once it's done. Another request can reuse the same connection (client) or use a different, idle one.