CODEWITHSUNDEEP
javasesameowlimgraphdb
user3572788
user3572788

Reputation: 151

How to set Sesame 2.8.0 RepositoryConnection timeout

I am trying to implement something like circuit breaker for my Sesame connections to the back-end database. When the database is absent I want to know this after 2 seconds, not to rely on the defaults of the client for timeouts. I can possibly overcome this with my own FutureTasks where I will execute the repository initialization and the connection obtaining. However in the logs I can see that sesame client uses o.a.h.i.c.PoolingClientConnectionManager - which is passed I bet ExecutorService and some default timeouts. This will make my FutureTask solution pretty messy. Is there an easier way to set timeouts for the sesame client.

Upvotes: 1

Views: 331

Answers (1)

Jeen Broekstra
Jeen Broekstra

Reputation: 22052

You can set the query and update timeout, specifically, on the query/update object itself:

 RepositoryConnection conn = ....;

 ... 
 TupleQuery query = conn.prepareTupleQuery(QueryLangage.SPARQL, "SELECT ...");
 query.setMaxExecutionTime(2);

However, if you want to set a general timeout for all api calls over HTTP, the only way to currently do that is by obtaining a reference to the HttpClient object, and reconfigure it:

  HTTPRepository repo = ....;
  AbstractHttpClient httpClient = (AbstractHttpClient)((SesameClientImpl)repo.getSesameClient()).getHtttpClient();
  HttpParams params = httpClient.getParams();
  params.setIntParameter(CoreConnectionPNames.SO_TIMEOUT, 2000);
  httpClient.setParams(params);

As you can see, this is rather brittle (lots of explicit casts), and uses an approach that is deprecated in Apache HttpClient 4.4. So I don't exactly recommend this as a stable solution, but it should provide a workaround in the short term.

In the longer term the Sesame dev team are working on more convenient access to the configuration of the httpclient.

Upvotes: 1

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