fix topic subscribing bug

[YujiOshima]

fix #425
Signed-off-by: Yuji Oshima yuji.oshima0x3fd@gmail.com

[codecov-io]

Codecov Report

Merging #426 into master will decrease coverage by -0.09%.
The diff coverage is 55.55%.

@@            Coverage Diff             @@
##           master     #426      +/-   ##
==========================================
- Coverage   62.75%   62.67%   -0.09%     
==========================================
  Files          72       72              
  Lines        4446     4455       +9     
==========================================
+ Hits         2790     2792       +2     
- Misses       1327     1331       +4     
- Partials      329      332       +3

Impacted Files	Coverage Δ
pkg/broker/server/sse.go	72.58% <55.55%> (-1.34%)	❌
pkg/broker/client/sse.go	61.62% <0%> (-3.49%)	❌

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[chungers]

Clever to do the check here.

Would you mind put this code in a function? Something like if !checkPath(key, event.topic) { return false }?

[chungers]

s/notfyTopic/notifyTopic/g

[YujiOshima]

Thank you, moved to function!

[chungers]

@YujiOshima Thank you for catching and fixing this bug and adding tests.

Once you move the check to a function I will merge it in.

I still think a better way is to intercept the subscribe call and reject a topic that doesn't conform to the spec of the Event plugin. This way, we don't have to do this check at every outbound event publish. It's also better UX since the client knows it tried to subscribe to an incorrect topic.

One place this might work, would be to add checks as an interceptor to the ServerHTTP handler. This would be the place: https://github.com/docker/infrakit/blob/master/pkg/rpc/server/server.go#L132

Here we have references to all the event.Plugin implementations and we can wrap the broker.ServeHTTP handler with a handler that does proper topic validation before they are forwarded on to the real thing. This would also give meaningful HTTP error code on subscription, rather than events quietly dropped to the floor. Finally the pkg/broker doesn't have to have any knowledge of / convention for topics and can be used for something that uses a different topic naming convention (maybe .object1.property1).

I will file that as a TO-DO....

[chungers]

LGTM