Missing streams after re-creation of the conference room

[dmitry027]

Hello, everybody.

The behavior of Ant Media when I am trying to create conference room having the same roomId multiple times via REST API is not entirely clear for me.

 

Steps to reproduce:

1. Open two tabs of the browser with conference demo https://localhost:5443/LiveApp/conference.html 

2. Create conference room via REST API:

curl -X 'POST' 'https://localhost:5443/LiveApp/rest/v2/broadcasts/conference-rooms' -H 'accept: application/json' -H 'Content-Type: application/json' -d '{
"roomId": "test_room"
}'

3. Join the room "test_room" in browser tab #1

4. Repeat create request: 

curl -X 'POST' 'https://localhost:5443/LiveApp/rest/v2/broadcasts/conference-rooms' -H 'accept: application/json' -H 'Content-Type: application/json' -d '{
"roomId": "test_room"
}'

5. Join the room "test_room" in the browser tab #2

 

What I expect to see:

I see two videos (local and remote) in browser tab #1 and two videos (local and remote) in browser tab #2

What I actually see:

I see two videos (local and remote) in browser tab #1 and only one video (local) in browser tab #2.

 

Is this behavior the expected one?

Edited December 1, 2022 by dmitry027
Fix format, add tags

[Yash]

Hi @dmitry027
I hope you are doing well.
After creating the room using Rest API before joining, you do not have to create the same room again for 2nd user. N no of viewers can join the same room. When you are creating the same room again, it is overwrites the details of previous room.

[dmitry027]

On 12/2/2022 at 2:40 PM, Yash said:

Hi @dmitry027
I hope you are doing well.
After creating the room using Rest API before joining, you do not have to create the same room again for 2nd user. N no of viewers can join the same room. When you are creating the same room again, it is overwrites the details of previous room.

Hello, @Yash. Thanks for you answer.

Yes, I understand that there is no need to create same room again for each user. My motivation is the following: when the first user joins the room, I want to be sure that the room that he is trying to join exists. So I make create call for each user joining the room, because I don't know if the room already exists or not.

The alternative way I see is to check the room existence by calling GET request and create the room only if I got 404 error. But I'm afraid in rare cases it can lead to the same situation because of concurrency (because room existence check and creation is not atomic):

1. User1 and User2 are trying to join the same room at the same time.

2. Both of my application workers check room existence (by calling 'GET /v2/broadcasts/conference-rooms/{room_id}') and got 404.

3. Both are trying to create the room.

4. The next steps for each worker is to create user stream (by calling 'POST /v2/broadcasts/create').

5. And associate it with the room (by calling PUT /v2/broadcasts/conference-rooms/{room_id}/add).

If worker-1 hangs between steps 2 and 3 (for some reason) while worker-2 reaches step 5, the worker-1 will rewrite the room created by the worker-2 when it will reach step 3 and first stream would be missing.

What do you think?