无法使用Rails和Paperclip上传图像

Question

I'm using Paperclip in my Rails app to handle image uploads. However, for some reason, every time I try to create a model instance that has an attached image, I'm getting a Rails 500 error.

What's strange is that restarting the app (via Upstart) then resubmitting the form allows me to upload images successfully, but it doesn't seem to "take": any subsequent uploads still give me a 500 error.

The production log is unhelpful and doesn't even show the POST request made to create the instance.

My Upstart config file:

description 'site.com'
author 'Daniel J. <>'

start on [2345]
stop on runlevel [016]

env PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
env RAILS_ENV=production
env SECRET_KEY_BASE=''
env DEVISE_SECRET_KEY=''
env POSTGRESQL_PASSWORD=''

setuid www-data
setgid www-data

chdir /var/www/site/current

pre-start exec bundle exec unicorn_rails -D -c /var/www/site/current/config/unicorn.rb --env production
post-stop exec kill `cat /var/www/site/current/tmp/pids/unicorn.pid`

My nginx file:

upstream app {
    server 127.0.0.1:3000;
}

server {
    listen               80               default;
    server_name          site.com;
    charset              utf-8;
    client_max_body_size 75M;
    root                 /var/www/site/current/public;

    location ~ ^/(assets)/ {
        gzip_static on;
        expires     max;
        add_header  Cache-Control public;
    }

    location / {
        try_files $uri/index.html $uri @app;
        error_page 404 /404.html;
        error_page 403 /403.html;
        error_page 422 /422.html;
        error_page 500 502 503 504 /500.html;
    }

    location = /favicon.ico {
        expires max;
        add_header Cache-Control public;
    }

    location @app {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_redirect off;
        proxy_pass http://app;
    }
}

And my Unicorn config file:

listen 3000
worker_processes Integer(ENV['WEB_CONCURRENCY'] || 3)
timeout 30
preload_app true
working_directory '/var/www/site/current'
stderr_path 'log/unicorn-error.log'
stdout_path 'log/unicorn-access.log'

before_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
    Process.kill 'QUIT', Process.pid
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.connection.disconnect!
end

after_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn worker intercepting TERM and doing nothing.  Wait for master to send QUIT.'
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.establish_connection
end

Answer 1

I figured out that it was a lack of memory on the box that did it. Once I added a swapfile (using the instructions here: https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04 ), I was able to successfully upload files.