我有一个在 Heroku 上运行的 Rails 3.2 应用程序，它每隔几秒钟输出以下 3 行。
Jun 20 11:03:32 xxxxxxxx app/web.1: limit
Jun 20 11:03:32 xxxxxxxx app/web.1: Response class: Net::HTTPOK
Jun 20 11:03:33 xxxxxxxx app/web.1: Response headers: {"content-type"=>["application/json"], "date"=>["Thu, 20 Jun 2013 10:03:32 GMT"], "content-length"=>["15"], "connection"=>["keep-alive"]}
我不知道这是从哪里来的，我无法在开发中重现它，而且我的应用程序代码中没有任何地方可以找到导致这种情况的原因。
任何想法可能会这样做，或者如何找出？
这是 Gemfile.lock：
GEM
remote: http://rubygems.org/
specs:
actionmailer (3.2.13)
actionpack (= 3.2.13)
mail (~> 2.5.3)
actionpack (3.2.13)
activemodel (= 3.2.13)
activesupport (= 3.2.13)
builder (~> 3.0.0)
erubis (~> 2.7.0)
journey (~> 1.0.4)
rack (~> 1.4.5)
rack-cache (~> 1.2)
rack-test (~> 0.6.1)
sprockets (~> 2.2.1)
activemodel (3.2.13)
activesupport (= 3.2.13)
builder (~> 3.0.0)
activerecord (3.2.13)
activemodel (= 3.2.13)
activesupport (= 3.2.13)
arel (~> 3.0.2)
tzinfo (~> 0.3.29)
activeresource (3.2.13)
activemodel (= 3.2.13)
activesupport (= 3.2.13)
activesupport (3.2.13)
i18n (= 0.6.1)
multi_json (~> 1.0)
addressable (2.3.4)
airbrake (3.1.12)
activesupport
builder
json
andand (1.3.3)
arel (3.0.2)
atomic (1.1.9)
attr_required (0.0.5)
bcrypt-ruby (3.0.1)
better_errors (0.9.0)
coderay (>= 1.0.0)
erubis (>= 2.6.6)
binding_of_caller (0.7.1)
debug_inspector (>= 0.0.1)
bootstrap-sass (2.2.2.0)
sass (~> 3.2)
bootswatch-rails (0.5.0)
railties (>= 3.1)
builder (3.0.4)
butler_static (0.0.9)
rack
rails (>= 3.1.0)
cache_digests (0.3.0)
actionpack (>= 3.2)
thread_safe
chronic (0.9.1)
climate_control (0.0.3)
activesupport (>= 3.0)
cocaine (0.5.1)
climate_control (>= 0.0.3, < 1.0)
coderay (1.0.9)
coffee-rails (3.2.2)
coffee-script (>= 2.2.0)
railties (~> 3.2.0)
coffee-script (2.2.0)
coffee-script-source
execjs
coffee-script-source (1.6.2)
css_parser (1.3.4)
addressable
cssminify (1.0.2)
daemons (1.1.9)
dalli (2.6.4)
debug_inspector (0.0.2)
delayed_job (3.0.5)
activesupport (~> 3.0)
delayed_job_ironmq (1.0.1)
delayed_job (~> 3.0.0)
iron_mq (>= 4.0.0)
delayed_job_null (0.0.4)
delayed_job (~> 3.0.0)
delorean (2.1.0)
chronic
devise (2.2.4)
bcrypt-ruby (~> 3.0)
orm_adapter (~> 0.1)
railties (~> 3.1)
warden (~> 1.2.1)
enum_column3 (0.1.4)
erubis (2.7.0)
eventmachine (1.0.3)
excon (0.22.1)
execjs (1.4.0)
multi_json (~> 1.0)
faraday (0.8.7)
multipart-post (~> 1.1)
fb_graph (2.7.1)
httpclient (>= 2.2.0.2)
multi_json (>= 1.3)
rack-oauth2 (>= 0.14.4)
tzinfo
flag_shih_tzu (0.3.2)
activerecord (>= 2.3.0)
fog (1.11.1)
builder
excon (~> 0.20)
formatador (~> 0.2.0)
json (~> 1.7)
mime-types
net-scp (~> 1.1)
net-ssh (>= 2.1.3)
nokogiri (~> 1.5.0)
ruby-hmac
font-awesome-sass-rails (3.0.2.2)
railties (>= 3.1.1)
sass-rails (>= 3.1.1)
formatador (0.2.4)
geocoder (1.1.8)
hash_extension (0.0.4)
hashie (2.0.5)
hike (1.2.2)
hpricot (0.8.6)
httparty (0.11.0)
multi_json (~> 1.0)
multi_xml (>= 0.5.2)
httpauth (0.2.0)
httpclient (2.3.3)
i18n (0.6.1)
ipaddr_list (0.0.2)
iron_core (0.6.2)
rest (>= 2.2.0)
iron_mq (4.0.3)
iron_core (>= 0.5.1)
journey (1.0.4)
jquery-rails (2.2.1)
railties (>= 3.0, < 5.0)
thor (>= 0.14, < 2.0)
json (1.8.0)
jwt (0.1.8)
multi_json (>= 1.5)
kaminari (0.14.1)
actionpack (>= 3.0.0)
activesupport (>= 3.0.0)
kgio (2.8.0)
lograge (0.2.0)
actionpack
activesupport
mail (2.5.4)
mime-types (~> 1.16)
treetop (~> 1.4.8)
memcache-client (1.8.5)
memcachier (0.0.2)
meta_request (0.2.1)
rack-contrib
rails
mime-types (1.23)
multi_json (1.7.4)
multi_xml (0.5.3)
multipart-post (1.2.0)
mysql2 (0.3.11)
net-http-persistent (2.8)
net-scp (1.1.1)
net-ssh (>= 2.6.5)
net-ssh (2.6.7)
newrelic_rpm (3.5.7.59)
nokogiri (1.5.9)
oauth2 (0.8.1)
faraday (~> 0.8)
httpauth (~> 0.1)
jwt (~> 0.1.4)
multi_json (~> 1.0)
rack (~> 1.2)
oj (2.0.14)
omniauth (1.1.4)
hashie (>= 1.2, < 3)
rack
omniauth-facebook (1.4.0)
omniauth-oauth2 (~> 1.0.2)
omniauth-oauth2 (1.0.3)
oauth2 (~> 0.8.0)
omniauth (~> 1.0)
orm_adapter (0.4.0)
paperclip (3.4.2)
activemodel (>= 3.0.0)
activerecord (>= 3.0.0)
activesupport (>= 3.0.0)
cocaine (~> 0.5.0)
mime-types
polyglot (0.3.3)
rack (1.4.5)
rack-auth-simples (0.0.10)
ipaddr_list (>= 0.0.2)
rack-cache (1.2)
rack (>= 0.4)
rack-contrib (1.1.0)
rack (>= 0.9.1)
rack-oauth2 (1.0.5)
activesupport (>= 2.3)
attr_required (>= 0.0.5)
httpclient (>= 2.2.0.2)
multi_json (>= 1.3.6)
rack (>= 1.1)
rack-protection (1.5.0)
rack
rack-reverse-proxy (0.4.4)
rack (>= 1.0.0)
rack-rewrite (1.3.3)
rack-ssl (1.3.3)
rack
rack-test (0.6.2)
rack (>= 1.0)
rails (3.2.13)
actionmailer (= 3.2.13)
actionpack (= 3.2.13)
activerecord (= 3.2.13)
activeresource (= 3.2.13)
activesupport (= 3.2.13)
bundler (~> 1.0)
railties (= 3.2.13)
railties (3.2.13)
actionpack (= 3.2.13)
activesupport (= 3.2.13)
rack-ssl (~> 1.3.2)
rake (>= 0.8.7)
rdoc (~> 3.4)
thor (>= 0.14.6, < 2.0)
raindrops (0.11.0)
rake (10.0.4)
rdoc (3.12.2)
json (~> 1.4)
redcarpet (2.3.0)
redis (3.0.4)
redis-namespace (1.3.0)
redis (~> 3.0.0)
rest (2.6.2)
net-http-persistent
rest-client (>= 0.3.0)
rest-client (1.6.7)
mime-types (>= 1.16)
roadie (2.3.4)
actionmailer (> 3.0.0, < 3.3.0)
css_parser
nokogiri (>= 1.4.4)
sprockets
rpm_contrib (2.1.11)
newrelic_rpm (>= 3.1.1)
newrelic_rpm (>= 3.1.1)
ruby-hmac (0.4.0)
sass (3.2.9)
sass-rails (3.2.6)
railties (~> 3.2.0)
sass (>= 3.1.10)
tilt (~> 1.3)
simple-random (0.9.3)
sinatra (1.3.6)
rack (~> 1.4)
rack-protection (~> 1.3)
tilt (~> 1.3, >= 1.3.3)
split (0.6.1)
redis (>= 2.1)
redis-namespace (>= 1.1.0)
simple-random
sinatra (>= 1.2.6)
sprockets (2.2.2)
hike (~> 1.2)
multi_json (~> 1.0)
rack (~> 1.0)
tilt (~> 1.1, != 1.3.0)
thin (1.5.1)
daemons (>= 1.0.9)
eventmachine (>= 0.12.6)
rack (>= 1.0.0)
thor (0.18.1)
thread_safe (0.1.0)
atomic
tilt (1.4.1)
treetop (1.4.12)
polyglot
polyglot (>= 0.3.1)
turbo-sprockets-rails3 (0.3.6)
railties (> 3.2.8, < 4.0.0)
sprockets (>= 2.0.0)
turbolinks (1.1.1)
coffee-rails
tzinfo (0.3.37)
uglifier (2.1.1)
execjs (>= 0.3.0)
multi_json (~> 1.0, >= 1.0.2)
unicorn (4.6.2)
kgio (~> 2.6)
rack
raindrops (~> 0.7)
unidecode (1.0.0)
warden (1.2.1)
rack (>= 1.0)
PLATFORMS
ruby
DEPENDENCIES
airbrake
andand
better_errors
binding_of_caller
bootstrap-sass (~> 2.2.2.0)
bootswatch-rails
butler_static
cache_digests
coffee-rails (~> 3.2.1)
cssminify
dalli
delayed_job
delayed_job_ironmq
delayed_job_null
delorean
devise
enum_column3
fb_graph
flag_shih_tzu
fog (~> 1.9)
font-awesome-sass-rails
geocoder
hash_extension (~> 0.0.4)
hpricot (>= 0.4)
httparty
jquery-rails
kaminari (~> 0.13)
kgio
lograge
memcache-client
memcachier
meta_request (= 0.2.1)
mysql2 (~> 0.3.2)
newrelic_rpm (~> 3.5.7.59)
oj
omniauth-facebook (= 1.4.0)
paperclip (~> 3.0)
rack-auth-simples
rack-reverse-proxy
rack-rewrite
rails (~> 3.2.8)
redcarpet
roadie
rpm_contrib
ruby-hmac (>= 0.3.2)
sass-rails
split
sprockets
thin
turbo-sprockets-rails3
turbolinks
uglifier (>= 1.0.3)
unicorn
unidecode