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SS supports many REST endpoints, some of them are used by POL. POL uses the following 2 SS REST two endpoints:
- /alive
This returns a timestamp (an a long integer) to indicate the start time of the SS. (long int, plain text)
Used for adding a SS in discoveryAMQ() if POL gets a valid long int, and removing a SS in heartbeat() if POL does not get a valid long int from the ep. - /applications
This returns a JSON array, such as "[{"alias":"daffodil","conversions":[{"inputs":["csv"],"outputs":["xml"]},{"inputs":["pgm"],"outputs":["xml"]}]},{"alias":"flac","conversions":[{"inputs":["aif","aiff","fla","flac","wav"],"outputs":["aif","aiff","fla","flac","wav"]}]}}}".
Used for adding a SS and updating the IO graph in discoveryAMQ().
Proposed design:
- SS registration with polyglot.
- Add 1 exchange/queue for SS registration with polyglot.
Set its TTL to say 5 secs, so msgs are discarded in such time. - SS publishes msgs to this queue, regarding aliveness, and conversion capabilities.
- Add 1 exchange/queue for SS registration with polyglot.
In "checkin", SS posts the content of a converted file and Polyglot saves it, instead of creating a "<file>.url" file.