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How to graciously abort a uaClient.connect() before the timeout
August 19, 2019
12:22, EEST
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hbrackel
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Good morning,

I have multiple OPC UA clients trying to connect to various OPC UA services (aka servers). In case any of the OPC UA servers does not respond, the corresponding UaClient.connect() calls *eventually* timeout (after the configured period).

Is there a way to prematurely graciously abort the client.connect() attempt? Are there any differences between the SDK versions 3.1.6 and 4.x?

Thanks,
Hans-Uwe

August 20, 2019
11:24, EEST
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Bjarne Boström
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Hi,

Not exactly at the moment. 4.0.0 added UaClient.setConnectTimeout(…), which makes easier to set the initial connection (i.e. Socket gets initial connection) timeout. Maybe you could start with quite optimistic timeout first and then increase it if a connect fails due to that?

August 20, 2019
13:26, EEST
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Jouni Aro
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You can also consider running the connect method in a worker thread so that your application doesn’t need to block and wait for the call to timeout if it takes too long.

At some point we considered adding a separate connectAsync method for that, but it turned out to be very complex – especially in comparison to how simple it is to do it yourself in a worker three suitable to your application.

August 20, 2019
13:49, EEST
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hbrackel
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We have remote servers over a high latency connection – so the timeout length is indeed needed. Sometimes though, the address of the server has been incorrectly configured and the new configuration shall be picked up as quickly as possible.
The connect() attempt is already running in a worker thread. While terminating the worker thread is possible, this would be “brute force” and eventually leave some resources in an undefined state – which I’d prefer to avoid.

August 20, 2019
15:39, EEST
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Jouni Aro
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Yes, that can be a bit tricky. I would say that it’s best to use the new ConnectTimeout for this.

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