NAME
dike
SYNOPSIS
a simple memory leak detector for ruby with preconfigured rails
hooks.
INSTALL
gem install dike
URIS
http://www.codeforpeople.com/lib/ruby/
http://rubyforge.org/projects/codeforpeople/
DESCRIPTION
the concept behind dike.rb is simple: class Object is extended in
order that
the location of each object’s creation is tracked. a summarizer
command is
given to walk ObjectSpace using each object’s class and the
location if it’s
creation to detect memory leaks. not all leaks can be detected
and some that
are may not really be leaks, but dike provided a simple way to see
the
hotspots in your code that may potentially be leaking.
EXAMPLES
PURE RUBY
## just dumping sequential snapshots to stderr
# cfp:~ > cat sample/a.rb
require 'dike'
Leaks = Array.new
loop do
Leaks << String.new('leak' * 1024)
Dike.finger
sleep 1
end
# cfp:~ > ruby sample/a.rb | less
...
- class: String
count: 2
trace:
- sample/a.rb:6
- sample/a.rb:5:in `loop'
- sample/a.rb:5
...
- class: String
count: 10
trace:
- sample/a.rb:6
- sample/a.rb:5:in `loop'
- sample/a.rb:5
...
- class: String
count: 42
trace:
- sample/a.rb:6
- sample/a.rb:5:in `loop'
- sample/a.rb:5
## dumping sequential snapshots using Dike.logfactory and then
using the ‘dike’
command line tool to do comparisons of the dumped snapshots
# cfp:~ > cat sample/b.rb
require 'dike'
Leaks = Array.new
class Leak
def initialize
@leak = 42.chr * (2 ** 20)
end
end
Dike.logfactory './log/'
Dike.finger
3.times{ Leaks << Leak.new }
Dike.finger
2.times{ Leaks << Leak.new }
Dike.finger
# cfp:~ > ruby sample/b.rb
# cfp:~ > ls log/
0 1 2
# cfp:~ > dike log/
---
- class: Leak
count: 3
trace:
- sample/b.rb:15
- sample/b.rb:15:in `times'
- sample/b.rb:15
- class: Leak
count: 2
trace:
- sample/b.rb:19
- sample/b.rb:19:in `times'
- sample/b.rb:19
# cfp:~ > dike log/0 log/1
---
- class: Leak
count: 3
trace:
- sample/b.rb:15
- sample/b.rb:15:in `times'
- sample/b.rb:15
# cfp:~ > dike log/1 log/2
---
- class: Leak
count: 2
trace:
- sample/b.rb:19
- sample/b.rb:19:in `times'
- sample/b.rb:19
RAILS
# cfp:~ > cat ./config/environment.rb
...
require 'dike'
Dike.on :rails
# cfp:~ > ./script/server
# cfp:~ > curl --silent http://localhost:3000 >/dev/null
# cfp:~ > cat ./log/dike/0
---
- class: String
count: 90769
trace: []
- class: Array
count: 18931
trace: []
- class: Class
count: 2
trace:
- votelink.com/public/../config/../lib/widgets.rb:222:in
class_factory' - votelink.com/public/../config/../lib/widgets.rb:220:in each’
- votelink.com/public/../config/../lib/widgets.rb:220:in
class_factory' - votelink.com/public/../config/../lib/widgets.rb:248:in Widget’
- votelink.com/public/../config/../lib/widgets/page/base.rb:1
- votelink.com/public/../config/../lib/widgets.rb:31:in
require' - votelink.com/public/../config/../lib/widgets.rb:31:in load’
- votelink.com/public/../config/../lib/widgets.rb:16:in
for_controller' - votelink.com/public/../config/../lib/widgets.rb:243:in widget’
- votelink.com/public/../config/../app/controllers/
application.rb:150
…
# cfp:~ > curl --silent http://localhost:3000 >/dev/null
# cfp:~ > cat ./log/dike/1
---
- class: String
count: 100769
trace: []
- class: Array
count: 19931
trace: []
- class: Class
count: 5
trace:
- votelink.com/public/../config/../lib/widgets.rb:222:in
class_factory' - votelink.com/public/../config/../lib/widgets.rb:220:in each’
- votelink.com/public/../config/../lib/widgets.rb:220:in
class_factory' - votelink.com/public/../config/../lib/widgets.rb:248:in Widget’
- votelink.com/public/../config/../lib/widgets/page/base.rb:1
- votelink.com/public/../config/../lib/widgets.rb:31:in
require' - votelink.com/public/../config/../lib/widgets.rb:31:in load’
- votelink.com/public/../config/../lib/widgets.rb:16:in
for_controller' - votelink.com/public/../config/../lib/widgets.rb:243:in widget’
- votelink.com/public/../config/../app/controllers/
application.rb:150
…
# cfp:~ > dike ./log/dike
...
- class: Class
count: 3
trace:
- votelink.com/public/../config/../lib/widgets.rb:222:in
class_factory' - votelink.com/public/../config/../lib/widgets.rb:220:in each’
- votelink.com/public/../config/../lib/widgets.rb:220:in
class_factory' - votelink.com/public/../config/../lib/widgets.rb:248:in Widget’
- votelink.com/public/../config/../lib/widgets/page/base.rb:1
- votelink.com/public/../config/../lib/widgets.rb:31:in
require' - votelink.com/public/../config/../lib/widgets.rb:31:in load’
- votelink.com/public/../config/../lib/widgets.rb:16:in
for_controller' - votelink.com/public/../config/../lib/widgets.rb:243:in widget’
- votelink.com/public/../config/../app/controllers/
application.rb:150
…
NOTES
-
the ‘Dike.finger’ method dumps it’s log in a format showing
class : the class of object being leaked/allocated
count : the number instances leaked from the trace location
trace : the trace location of object creation -
loading into a rails environment causes snapshots of the above
format to
be dumped into RAILS_ROOT/log/dike/ after each request. each
snapshot is
incrementally numbered 0, 1, … -
the ‘dike’ command line tool can be used in two ways
dike directory/with/logs/dike/
dike old_dump new_dump
if given a directory ‘old_dump’ and ‘new_dump’ are auto-
calculated by
scanning the directory. in either case the tool dups a delta
running old
–>> new. the delta shows only changes from old to new, so a
line like- class: Proc
count: 3
…
means that 3 Proc objects were created between the two dumps.
note that,
when given a directory, the default old and new dumps are the
oldest and
newest dumps respectively, to get fine grained information
sumarizing the
changes between two requests give the files manually, for exampledike ./log/dike/41 ./log/dike/42
- class: Proc
-
options that affect logging
-
Dike.filter pattern
pattern must respond to ‘===’ and each object in ObjectSpace
will be
compared against it. for exampleDile.filter Arraywould cause logging to restrict itself to Array, or
sublcasses of
Array -
Dike.log io
set the dike logging object. the object should respond to
‘puts’. -
Dike.logfactory directory
cause logging to occur into a new log for each call the
‘Dike.finger’.
the logs will be auto numbered 0, 1, …
-
LIMITATIONS
not all object creation can be tracked. not all leaks are
reported. some
reported leaks are not. dike shows you where in the source objects
are being
created that cannot be reclaimed - these are not always leaks as
this line
class C; end
shows. the class ‘C’ cannot be reclaimed and is not a leak.
AUTHOR
ara [dot] t [dot] howard [at] gmail [dot] com
enjoy.