CODEWITHSUNDEEP
httptimeoutamazon-s3amazon-ec2
Stormshadow
Stormshadow

Reputation: 7159

HTTP 504 timeout after exactly 120 seconds

I have a server application which runs in the Amazon EC2 cloud. From my client (the browser) I make a HTTP request which uploads a file to the server which then processes the file. If there is a lot of processing (large file ), the server always times out with a 504 backend continuation error always exactly after 120 seconds. Though I get this error, the server continues to process the request and completes it (verified by checking the database) but I cannot see the final result on my client because of the timeout.

I am clueless as to why this is happening. Has anyone faced a similar 504 timeout ? Is there some intermediate proxy server not in my control which is timing out ?

Upvotes: 7

Views: 13207

Answers (3)

Jelle van Geuns
Jelle van Geuns

Reputation: 893

I have a similar problem and in my case I believe it is due to the connection between the Elastic Load Balancer (ELB) and the EC2 instance.

For a long-term solution I will go with the 303 Status response + back-end processing suggested by james.garriss above.

For short-term solution it may be possible for Amazon support to increase the ELB timeout (see their response in https://forums.aws.amazon.com/thread.jspa?messageID=491594&#491594). Unfortunately there doesn't seem to be any way to change the timeout yourself through either API or console.

[Update] AWS now does allow you to update the idle timeout either through console, CLI or .ebextensions configuration. See http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/config-idle-timeout.html (thanks @Daniel Patz for the update)

Upvotes: 7

james.garriss
james.garriss

Reputation: 13388

Assuming that the correct status code is being returned, the problem is that an intermediate proxy is timing out. "The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI." (http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.5) It most likely indicates that the origin server is having some sort of issue (i.e., taking a long time to process your request), so it's not responding quickly.

Perhaps the best solution is to re-craft your server app so that it responds with a "303 See Other" status code; then your client can retrieve the data at a later data point, once the server is done processing and creates the final result.

Edit: Another idea is to re-craft your server app so that it responds with a "413 Request Entity Too Large" status code when the request entity size is too large. This will get rid of the error, though it may make your app less useful if it can only process "small" files."

Other possible solutions:

  • Increase timeout value of the proxy (if it's under your control)
  • Make your request to a different server (if there's another, faster server with the same app)
  • Make your request differently (if possible) such that you are sending less data at a time

Upvotes: 2

Paul Ma
Paul Ma

Reputation: 615

it is possible that the browser timeouts during the script execution.

Upvotes: 0

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