[REEF-2032] DriverStatusHTTPHandler causes timeout to Http Request if there is no Driver status change

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: REEF Bridge, REEF Driver
• Assignee: Unassigned
• Reporter: Chenxi Zhao
• Created: 05/Jun/18 17:53
• Updated: 05/Jun/18 17:53

Description

As a HTTP Handler, it should response to every HTTP request to the endpoint "driverstatus/v1". 

 

However, instead of recording the current Driver status, in DriverStatusHTTPHandler, it uses a queue to only save the change. If there is no change in Driver status, every HTTP requests will timeout. 

 

The problem is in:

https://github.com/apache/reef/blob/master/lang/java/reef-bridge-client/src/main/java/org/apache/reef/bridge/client/DriverStatusHTTPHandler.java#L154

 

 Reproduce:

1. Modify HelloTask - add a while loop to print "Hello, REEF!" to prevent driver from exiting.
2. Send HTTP request "http://IP:Port/driverstatus/v1" to query driver status multiple times.

 

Observation:

1. I am able to see Driver Status "INIT", "RUNNING"
2. From this point on, all HTTP requests to this handler will timeout, unless Driver status changes again.

 

Expectation:

HTTP server should response with current Driver status at anytime.