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RabbitMQ for Thumbnail generation in cloud

We are an cloud based fileshare and backup company. A frequent requirement for customers is to share their data with other people, for e.g. some customers will have people who will upload stock photos and the customer want to first look at thumbnail before really downloading the large picture. We were earlier using disk based queuing and there was a process that was running at night that used to come around and generate thumbnails. This was working earlier as most of the customers didn't had time sensitive thumbnail generation requirements. Now as we had grown the customer base has grown and people wanted their thumbnails to be generated instantaneously. So I came up with the architecture as shown in the image.



We use the new RabbitMQ with persister so that if it goes down the message are preserved. App nodes are tomcat servers that uses Java api to push messages to Rabbit as soon as a file is uploaded by the user and we also queue a message to scribe in case pushing a message to rabbit was unsuccessful. RabbitMQ client sometimes drops connection if the appserver is under a heavy load so scribe is the fallback.

We run python thumbnail rabbit consumers  on multiple machines, the code is very simple and it open a channel and waits for a message, as soon as the message comes we use PIL to generate the thumbnail. The scribe consumer queues the message to rabbitmq for message that we were not able to log to rabbitmq synchronously.

Now the response time of thumbnail generation under normal condition is under 5 sec. We can improve it further by starting more consumers but we are not a facebook ;) so we had started only 1 consumer so far with 10 threads and performance of RabbitMQ and PIL rocks.

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  1. pacmanJuly 8, 2010 at 11:48 AM

    really interesting post. Please could you provide any link or example on ho to use the persister with rabbit mq?

    ReplyDelete
  2. Kalpesh PatelJuly 9, 2010 at 12:19 AM

    We downloaded bug21673 branch and did some performance tests and built on top of it.

    The rabbitmq guys specially matthew is very helpful so you can always post them and they fast in replying to mailing-list.

    Regards
    -Kalpesh

    ReplyDelete

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