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Tigge / openant

ANT and ANT-FS Python Library
MIT License
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Timeout issues and filter module #6

Open Toilal opened 9 years ago

Toilal commented 9 years ago

I often have to start antfs-cli again 1 or 2 times to get the files downloading without those timeout issues.

I think there's a small design issue in ant.easy.filter module that prevents protocol error message to be displayed properly to the user, and that could be used to retry the request properly.

wait_for_message function works nicely when all is working like expected. But the output is cryptic when the device sends an error message.

There are some hardcoded events (EVENT_TRANSFER_TX_FAILED & EVENT_RX_FAIL_GO_TO_SEARCH) that raise a more readable error, but i think an explicit error message should be displayed for every possible error message. Also, the retry on error should be more explicit.

Maybe the signature of wait_for_message(match, process, queue, condition) could be changed to something like wait_for_message(match, error_match, process, queue, condition) where error_match is a function that returns an Exception if an error message has been received ?

Tigge commented 9 years ago

Yeah, this is one of the worst problems with openant. It should be possible to recover from most problems, even if it means you have to go to search and restart communication. There is some error recovery in openant but obviously it is not enough.

More explicit error messages, i.e. more types of different exceptions is probably a good start. Not sure where the added error_match would be usable. Do you have an example?

Toilal commented 9 years ago

Currently, i didn't analyze enough to find out exactly where the error_match could be use, but i was just thinking on this API change to recover properly from expected possible errors when using the wait_for_message function.

I'll try to make more tests and build a PR to enhance this part of openant in the next few days.

Do you have access to any documentations about those events ? Best source i've found is here : https://devzone.nordicsemi.com/answers/18680/revisions/ but maybe you have something more precise ?

Tigge commented 9 years ago

You want the official documentation on http://www.thisisant.com/developer/resources/downloads/#documents_tab. A lot of the documentation is freely available. The ANT Message Protocol and Usage is documenting the ANT protocol, probably want to start there. The channel events are in section 9.5.6.

This document have been updated since I last looked at it so the feature gap from openant to this current version of the standard is probably a bit larger now.

Tigge commented 9 years ago

The documentation that are not available freely is mostly related to ANT-FS, ANT+ and FIT -- those unfortunately requires you to agree to the ANT Adopters agreement or the FIT license to read, just so you are aware of that, which adds some restrictions on you. But for the ant.base and ant.easy modules the freely available documents should be enough.