Rails 4.2: Internal Server Error with Maximum file multiparts in content reached

Question

Just upgraded to Rails 4.2 and I get Internal Server Error on localhost and in production when trying to edit a model with multiple has_many objects. This is the message I see on the rails s console

!! Unexpected error while processing request: Too many open files - Maximum file multiparts in content reached

The request does not even get to the controller i.e., I DO NOT see the usual following lines in rails s console

Started GET "/feeds/3/edit" for 127.0.0.1 at 2015-01-04 20:07:19 -0800
Processing by FeedsController#edit as HTML
......
......

Any clues?? Using Ruby 2.1.5 upgraded to 2.2 with no luck.

Getting the same thing here, Rails 4.2.0 and Ruby 2.2.0. – Craig Knox Jan 05 '15 at 16:54 — Craig Knox, Jan 05 '15 at 16:54
Rack 1.6.4 contains a fix for this. – John Naegle Jun 19 '15 at 15:18 — John Naegle, Jun 19 '15 at 15:18

score 73 · Accepted Answer · answered Jan 05 '15 at 17:15

73

It looks like the multipart limit was added in the Rails 4.2 version of Rack (https://github.com/rack/rack/commit/b0b5fb9467e6ed777d3eaf35afc81d758e308aab). The default is 128, which may be too little for your purposes, it was for mine. Setting the value to 0 in an initializer removes the limit and fixes the problem:

Rack::Utils.multipart_part_limit = 0

I would suggest tailoring the value until it fits your needs so your server doesn't run out of file handles. My app uses a massive form and setting it to 512 seemed to work for me.

answered Jan 05 '15 at 17:15

Craig Knox

916
8
8

2

Thank you Craig. Will test and mark your answer as accepted if it works. I do have a long form. The shorter forms work fine. – anu Jan 06 '15 at 04:46
3

It looks to us like the patch that was introduced is counting one open file per form element, not just files. So if you have a nested form, you quickly run out of "files". Seems like a bad patch. – Rob Mar 02 '15 at 19:57
Rack 1.6.1 does NOT contain this fix. Looks like that will be in the 1.7 release instead :( – John Naegle May 12 '15 at 11:49
4

Rack 1.6.4 contains a fix for this. – John Naegle Jun 19 '15 at 15:18
Hey i m facing the same problem,Where i can place this line? – Jigar Bhatt Aug 24 '15 at 10:55
2

@JigarBhatt I place it in config.ru, for reference – Weihang Jian Dec 23 '15 at 06:21

score 14 · Answer 2 · edited Apr 14 '15 at 15:06

14

You can also pass a Environment variable to the app, as you can see here(https://github.com/rack/rack/blob/8d21788798b521b97beb10047ebf593ddc0aaed2/lib/rack/utils.rb#L75).

RACK_MULTIPART_PART_LIMIT=0 rails server

edited Apr 14 '15 at 15:06

gef

7,025
4
41
48

answered Jan 14 '15 at 13:12

Scudelletti

1,470
17
19

3

But you should set both `RACK_MULTIPART_PART_LIMIT` and `RACK_MULTIPART_LIMIT` because of the code remark _RACK_MULTIPART_LIMIT was introduced by mistake and it will be removed in 1.7.0_ – anka May 29 '15 at 08:54
Hey i m facing the same problem,Where i can place this line? – Jigar Bhatt Aug 24 '15 at 10:55
1

@JigarBhatt you can set this env variables on the line that you execute your script. For example: `RACK_MULTIPART_PART_LIMIT=0 ruby app.rb` or you can export you variable an then run your script. `export RACK_MULTIPART_PART_LIMIT=0 ` then `ruby app.rb` – Scudelletti Aug 30 '15 at 20:01

score 6 · Answer 3 · answered Mar 02 '15 at 20:53

6

It looks like there is a bug in Rack 1.6 where all HTML input elements get counted as an open file in a multipart form. As others point out, you can change the limit to 0 to disable the feature, or bump the limit.

https://github.com/rack/rack/pull/814

answered Mar 02 '15 at 20:53

John Naegle

8,077
3
38
47

This has been merged into 1.6.4 it appears – John Naegle Jun 19 '15 at 15:17

Rails 4.2: Internal Server Error with Maximum file multiparts in content reached

3 Answers3

Linked