nginx-push-stream-module
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wandenberg
Purge old messages when out of memory
Hello.
As I can see in the push_stream_shared_memory_size description:
The size of the memory chunk this module will use to store published messages, channels and other shared structures. When this memory is full any new request for publish a message or subscribe a channel will receive an 500 Internal Server Error response.
What is supposed to do when you get 500 trying to publish a mesasge?
I would prefer to have another option of the module behavior. I think it should (optionally) free memory when it needs more by freeing old messages. This way push_stream_message_ttl would have logic more like "try to keep messages for push_stream_message_ttl but can also delete them earlier".
E.g. this policy is available in Redis ( http://oldblog.antirez.com/post/redis-as-LRU-cache.html ):
Another way to use Redis as a cache is the maxmemory directive, a feature that allows specifying a maximum amount of memory to use. When new data is added to the server, and the memory limit was already reached, the server will remove some old data deleting a volatile key, that is, a key with an EXPIRE (a timeout) set, even if the key is still far from expiring automatically.
What do you think?
It's a must have.
Some API to delete stored messages will be great too, but it's more advanced feature, so just freeing memory as needed will be ok.
