Enables other subsystems to watch actions for a plugin(s).
This will be used specifically for implementing plugins on swarm where a
swarm controller needs to watch the state of a plugin.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
benchmark old ns/op new ns/op delta
BenchmarkPubSub-8 1036494796 1032443513 -0.39%
benchmark old allocs new allocs delta
BenchmarkPubSub-8 2467 1441 -41.59%
benchmark old bytes new bytes delta
BenchmarkPubSub-8 212216 187792 -11.51%
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
inotify event is trigged immediately there's data written to disk.
But at the time that the inotify event is received, the json line might
not fully saved to disk. If the json decoder tries to decode in such
case, an io.UnexpectedEOF will be trigged.
We used to retry for several times to mitigate the io.UnexpectedEOF error.
But there are still flaky tests caused by the partial log entries.
The daemon knows exactly when there are new log entries emitted. We can
use the pubsub package to notify all the log readers instead of inotify.
Signed-off-by: Shijiang Wei <mountkin@gmail.com>
try to fix broken test. will squash once tests pass
Signed-off-by: Shijiang Wei <mountkin@gmail.com>
A TopicFunc is an interface to let the pubisher decide whether it needs
to send a message to a subscriber or not. It returns true if the
publisher must send the message and false otherwise.
Users of the pubsub package can create a subscriber with a topic
function by calling `pubsub.SubscribeTopic`.
Message delivery has also been modified to use concurrent channels per
subscriber. That way, topic verification and message delivery is not
o(N+M) anymore, based on the number of subscribers and topic verification
complexity.
Using pubsub topics, the API stops controlling the message delivery,
delegating that function to a topic generated with the filtering
provided by the user. The publisher sends every message to the
subscriber if there is no filter, but the api doesn't have to select
messages to return anymore.
Signed-off-by: David Calavera <david.calavera@gmail.com>
