Notify activation / alive connection

[BigfootN]

Hello,

I am using zbus to connect to an mpris2 dbus bus / player.

When running my code, and when my player is not running, zbus won't connect to the bus. Obviously since my player is not running.

My code is supposed to watch a property thanks to PropertyStream. When I than launch my player while my program is still running, the PropertyStream continues to block, as if my player wasn't launched.

Is there a way to "notify" my connection (PropertyStream) that my player has been launched (is running) so that it can fetch new data through my PropertyStream ?

Hoping I was clear enough.

Thank you very much in advance for any help.

[zeenix]

When running my code, and when my player is not running, zbus won't connect to the bus. Obviously since my player is not running.

Actually that's not correct. zbus will still connect to the bus as the bus lives independent of your service. You can also create a proxy to the service just fine w/o any problems.

My code is supposed to watch a property thanks to PropertyStream. When I than launch my player while my program is still running, the PropertyStream continues to block, as if my player wasn't launched.

The stream is waiting on PropertiesChanged signal from the service. I'd guess that your player is not sending these out at the start and hence the stream keeps waiting.

Is there a way to "notify" my connection (PropertyStream) that my player has been launched (is running) so that it can fetch new data through my PropertyStream ?

You can wait on your player to start before creating the proxy and the property stream using https://docs.rs/zbus/latest/zbus/proxy/struct.Proxy.html#method.receive_owner_changed but it might be best if the player sent out PropertiesChanged signal in the beginning.

I think this is something zbus could help with and the proxy should do this for you. I created #1172 for this.

[BigfootN]

Thank you for your quick response, and sorry for my late one.

I'd guess that your player is not sending these out at the start and hence the stream keeps waiting.

Well it's supposed to. When my code runs after launching my player, the PropertyStream "works". The player sends the PropertiesChanged. But it simply doesn't seem to work when running my code before running my player. (I tested with spotify)

Just to be sure I am not wrong (I could be) I would advise you to test it yourself:

1. Make sure the player is not running
2. Write some simple code that is supposed to stream a property that sends PropertiesChanged
3. Run the code
4. Run the player
5. See if the property is fetched once the player is up and running

You can wait on your player to start before creating the proxy and the property stream using https://docs.rs/zbus/latest/zbus/proxy/struct.Proxy.html#method.receive_owner_changed

Does this method return Some once the player is up and running (after being "dead" / disconnected) ?

I think this is something zbus could help with and the proxy should do this for you. I created #1172 for this.

Thank you very much for this

[zeenix]

Well it's supposed to. When my code runs after launching my player, the PropertyStream "works". The player sends the PropertiesChanged. But it simply doesn't seem to work when running my code before running my player.

You can use the busctl monitor command to ensure that the PropertiesChanged signal is sent out and if it does, then that's a different bug (in addition to #1172) then.

ust to be sure I am not wrong (I could be) I would advise you to test it yourself:

1. Make sure the player is not running
2. Write some simple code that is supposed to stream a property that sends PropertiesChanged
3. Run the code
4. Run the player
5. See if the property is fetched once the player is up and running

If you could use these to create a minimal reproducer (you can create a super simple interface through zbus that sets the property periodically and add the interface after the proxy is setup and waiting (maybe in another task or thread) and include it in an issue, that would greatly help in solving this bug.

You can wait on your player to start before creating the proxy and the property stream using https://docs.rs/zbus/latest/zbus/proxy/struct.Proxy.html#method.receive_owner_changed

Does this method return Some once the player is up and running (after being "dead" / disconnected) ?

Yes, more correctly, it gives you a stream that yields Some when the name is taken, which is typically done by the service at launch.

[zeenix]

Oh and btw, please make sure you're using zbus 5 (I won't be able to support you on older versions).

[BigfootN]

Hello,

Thank you for your quick response.

Unfortunately I haven't had much time these last few days to answer. Sorry.

If you could use these to create a minimal reproducer (you can create a super simple interface through zbus that sets the property periodically and add the interface after the proxy is setup and waiting (maybe in another task or thread) and include it in an issue, that would greatly help in solving this bug.

Thank you I'll do that in the issue you've posted if that's okay with you

Yes, more correctly, it gives you a stream that yields Some when the name is taken, which is typically done by the service at launch.

Thank you for this I'll use this as a "workaround" to check if the service is up and running and check if I need to "recreate a connection"

Oh and btw, please make sure you're using zbus 5 (I won't be able to support you on older versions).

Indeed, I'm using the last version (5.1.1).

Thank you for your help and time.