Q:Heroku Zbar Didn't find libzbar on your system (LoadError)

[yoshidaagri]

I have a rails application which uses zbar. It works fine on my developer machine But when i tried to deploy it to Heroku my commit was rejected with the following message:

app/web.1: /app/vendor/bundle/ruby/2.0.0/gems/zbar-0.2.2/lib/zbar/lib.rb:12:in rescue in <module:ZBar>': Didn't find libzbar on your system (LoadError) app/web.1: Please install zbar (http://zbar.sourceforge.net/) or set ZBAR_LIB if it's in a weird place app/web.1: FFI::Library::ffi_lib() failed with error: library names list must not be empty app/web.1: from /app/vendor/bundle/ruby/2.0.0/gems/zbar-0.2.2/lib/zbar/lib.rb:9:inmodule:ZBar'

Here is my gemfile;
gem 'zbar', '~> 0.2.2'

my /.buildpacks:
https://github.com/ballantyne/heroku-buildpack-zbar
https://github.com/heroku/heroku-buildpack-ruby.git

Why does this happen?
Thanks.

[willglynn]

It looks like that buildpack is putting libzbar.so in /app/vendor/lib. I'd say that qualifies as a weird place, and the zbar gem doesn't look for it there, so it doesn't find it. Try setting the ZBAR_LIB environment variable (i.e. config variable) directly:

$ heroku config:set ZBAR_LIB=/app/vendor/lib/libzbar.so

If it's not there, try heroku run bash to poke around inside the slug and find its precise location and filename.

[yoshidaagri]

thanks for the help! deploy completed.

but method from_jpeg fails with "JPEG datastream contains no image
Your libzbar has a JPEG bug. Some images will fail to process correctly.
See: https://github.com/willglynn/ruby-zbar/blob/master/lib/zbar/jpeg.rb ".

my application controller.create:
@upload_file = params[:app][:image];
@barcode = ZBar::Image.from_jpeg(@upload_file.read).process;

What should I do?
Old libzbar in the buildpack?

[willglynn]

What should I do?
Old libzbar in the buildpack?

It's not so much old as it is unpatched. The current release version (zbar-0.10) has a bug that makes it break when handling various JPEGs. The zbar gem has a runtime check for this bug and warns you when it detects failure. Applying the patch at https://gist.github.com/willglynn/5659946 fixes it.

I think the right way to do this would be to fork the buildpack, add the patch file, apply it hereabouts, and open a pull request with the buildpack maintainer to get it merged upstream.

[andyweiss1982]

Hi there, I am having the same problem but the fix outlined in this thread did not work for me. I tried heroku run bash and navigated into vendor but there is no lib folder.

Any advice as to how I can find the correct path? The library is working just fine on my local machine.

[andyweiss1982]

Updates on this end -- I am now using the following buildpacks:

https://github.com/generalui/heroku-buildpack-zbar
https://github.com/heroku/heroku-buildpack-ruby

I can see in the compilation that zbar is being installed.

and in heroku run bash I see a zbar folder

but I don't see a libzbar.so file and the deploy is still failing:

Is there a better buildpack that you recommend? I see many "yet to be official" heroku zbar buildpacks on github but haven't had success with any.

Thanks for your work on this library!

[willglynn]

I have limited connectivity at the moment, but try something like:

$ heroku run bash
…
~ $ find / -name '*zbar*.so*`

Hopefully there's a libzbar.so somewhere in your slug. (It looks like the linked buildpack does a make install, so maybe it's in /usr/local/lib?) Assuming you find one, inform the zbar gem using an environment variable:

$ heroku config:set ZBAR_LIB=/path/to/libzbar.so

Hope that helps!

[andyweiss1982]

Hi Will, thanks for the advice -- I see a libzbar.rc but no libzbar.so. Should I probably try another buildpack?

[michaelryu]

Having the same problem, I can't find libzar even with the command. It's not located in the usr/local path either.

[michaelryu]

So after contacting the zbar-buildpack owner, he recommended using the apt-buildpack instead. It looked like it was going to work because it installed libzbar0 just fine but it didn't create a libzbar.so file so I tried libzbar-dev.

libzbar-dev created a libzbar.so file in /app/.apt/usr/lib/libzbar.so

Unfortunately when I point to it in heroku config
heroku config:set ZBAR_LIB=/app/.apt/usr/lib/libzbar.so, it still displays

LoadError: Didn't find libzbar on your system
remote:        Please install zbar (http://zbar.sourceforge.net/) or set ZBAR_LIB if it's in a weird place
remote:        FFI::Library::ffi_lib() failed with error: library names list must not be empty'

[andyweiss1982]

@michaelryu, I am posting a stack overflow question about this in case anyone in the community has had any success with it. Please upvote! http://stackoverflow.com/questions/31812168/how-can-i-get-zbar-to-deploy-on-heroku

[andyweiss1982]

@michaelryu I am now in the same place as you.

I used the apt-buildpack:

`=== testing-aptfile Buildpack URLs

1. https://github.com/ddollar/heroku-buildpack-apt
2. https://github.com/heroku/heroku-buildpack-ruby`

And I made an Aptfile, saved it to root, with only the word “libzbar-dez” in it.

I was able to find a libzbar.so file — this is progress for me!

Running bash attached to terminal... up, run.5242 ~ $ find / -name "libzbar.so" /app/.apt/usr/lib/libzbar.so

I set the ENV variable ZBAR_LIB.

ZBAR_LIB: /app/.apt/usr/lib/libzbar.so

But when I push to Heroku, I get the same error message as before:

remote: LoadError: Didn't find libzbar on your system remote: Please install zbar (http://zbar.sourceforge.net/) or set ZBAR_LIB if it's in a weird place remote: FFI::Library::ffi_lib() failed with error: Could not open library '/app/.apt/usr/lib/libzbar.so': /app/.apt/usr/lib/libzbar.so: cannot open shared object file: No such file or directory

@willglynn Do you see anything I might be doing wrong here? Anything you might see would be a huge help.

[willglynn]

Hmm:

…
/app/.apt/usr/lib/libzbar.so: cannot open shared object file: No such file or directory

This path appears in find(1) output, but open(2) returns ENOENT? Is it a symlink to a nonexistent path, or something?

Now I'm curious about the output of:

$ heroku run bash
…
~ $ ls -l /app/.apt/usr/lib/libzbar.so
~ $ file /app/.apt/usr/lib/libzbar.so

[andyweiss1982]

Hi @willglynn, thanks for following up. I'm still stuck!

Here is the ouput of the terminal commands:

$ heroku run bash Running bashattached to terminal... up, run.3002 ~ $ ls -l /app/.apt/usr/lib/libzbar.so lrwxrwxrwx 1 u16314 16314 16 Oct 22 2013 /app/.apt/usr/lib/libzbar.so -> libzbar.so.0.2.0 ~ $ file /app/.apt/usr/lib/libzbar.so /app/.apt/usr/lib/libzbar.so: symbolic link tolibzbar.so.0.2.0'`

[willglynn]

Does libzbar.so.0.2.0 exist too? The ENOENT seems to imply that it does not.

[andyweiss1982]

looks like it does -- good sign?

$ heroku run bash Running bash attached to terminal... up, run.3824 ~ $ find / -name "libzbar.so.0.2.0" /app/.apt/usr/lib/libzbar.so.0.2.0

[andyweiss1982]

I tried setting ZBAR_LIB to /app/.apt/usr/lib/libzbar.so.0.2.0 but still getting the same error with these two buildpacks:

1. https://github.com/ddollar/heroku-buildpack-apt
2. https://github.com/heroku/heroku-buildpack-ruby

remote: LoadError: Didn't find libzbar on your system remote: Please install zbar (http://zbar.sourceforge.net/) or set ZBAR_LIB if it's in a weird place remote: FFI::Library::ffi_lib() failed with error: Could not open library '/app/.apt/usr/lib/libzbar.so.0.2.0': /app/.apt/usr/lib/libzbar.so.0.2.0: cannot open shared object file: No such file or directory

[willglynn]

Could you make a test case repo I can clone and deploy to Heroku? I don't understand why it's failing with No such file or directory, but given a Heroku app I can touch, I'll have much better visibility.

[andyweiss1982]

Sure thing, thanks so much for following me through this. This is a more or less blank repo: https://github.com/andyweiss1982/aptfile-test

All I have added is the Aptfile with the string "libzbar-dev" in it, and placed a barcode.jpg in the public folder. This is the heroku url, but there is an application error related to the deploy issues: https://aptfile-test.herokuapp.com/

If you send me your email address, I can add you as a collaborator on heroku so you can see that side as well. My email is my github username at gmail dot com.

Thanks again!

[willglynn]

I started a bash dyno, from which I ran a rails console, showing:

$ heroku run bash --app aptfile-test
…
~ $ bin/rails console
Loading production environment (Rails 4.2.2)
irb(main):001:0> ZBar::JPEG.bugged?
JPEG datastream contains no image
=> true
irb(main):002:0> 

The "JPEG datastream contains no image" messaage is emitted directly to stdout from the bowels of libzbar, and ZBar::JPEG.bugged? makes two different calls to libzbar to distinguish failure modes, so the Ruby gem is definitely communicating with the C shared library as of now.

Checking the Heroku logs, release v9 seems to have been failing:

2015-08-07T17:35:31.979295+00:00 heroku[api]: Deploy b59b15e by andyweiss1982@…
2015-08-07T17:35:31.979295+00:00 heroku[api]: Release v9 created by andyweiss1982@…
2015-08-07T17:35:32.163269+00:00 heroku[slug-compiler]: Slug compilation started
2015-08-07T17:35:32.163352+00:00 heroku[slug-compiler]: Slug compilation finished
2015-08-07T17:35:32.078989+00:00 heroku[web.1]: State changed from crashed to starting
2015-08-07T17:35:35.046174+00:00 heroku[web.1]: Starting process with command `bin/rails server -p 40370 -e production`
2015-08-07T17:35:38.292950+00:00 app[web.1]: /app/vendor/bundle/ruby/2.0.0/gems/zbar-0.2.2/lib/zbar/lib.rb:12:in `rescue in <module:ZBar>': Didn't find libzbar on your system (LoadError)
2015-08-07T17:35:38.292973+00:00 app[web.1]: Please install zbar (http://zbar.sourceforge.net/) or set ZBAR_LIB if it's in a weird place
2015-08-07T17:35:38.292975+00:00 app[web.1]: FFI::Library::ffi_lib() failed with error: Could not open library '/app/.apt/usr/lib/libzbar.so.0.2.0': /app/.apt/usr/lib/libzbar.so.0.2.0: cannot open shared object file: No such file or directory

…while release v10 seems to work:

2015-08-07T17:46:12.432372+00:00 heroku[api]: Deploy 27f93d1 by andyweiss1982@…
2015-08-07T17:46:12.432372+00:00 heroku[api]: Release v10 created by andyweiss1982@…
2015-08-07T17:46:12.481196+00:00 heroku[slug-compiler]: Slug compilation started
2015-08-07T17:46:12.481220+00:00 heroku[slug-compiler]: Slug compilation finished
2015-08-07T17:46:13.024050+00:00 heroku[web.1]: State changed from crashed to starting
2015-08-07T17:46:17.670078+00:00 heroku[web.1]: Starting process with command `bin/rails server -p 26120 -e production`
2015-08-07T17:46:25.868205+00:00 heroku[web.1]: State changed from starting to up
2015-08-07T17:46:25.665639+00:00 app[web.1]: [2015-08-07 17:46:25] INFO  WEBrick 1.3.1
2015-08-07T17:46:25.665774+00:00 app[web.1]: [2015-08-07 17:46:25] INFO  ruby 2.0.0 (2015-04-13) [x86_64-linux]
2015-08-07T17:46:25.666333+00:00 app[web.1]: [2015-08-07 17:46:25] INFO  WEBrick::HTTPServer#start: pid=3 port=26120

https://aptfile-test.herokuapp.com/ currently returns a 404 from the dyno rather than a 503 App Crashed from Heroku's router.

So… it's fixed? What was the issue?

[andyweiss1982]

This is the strangest thing.

So I went ahead and coded out a barcode scan on the aptfile-test app and pushed it again to heroku, not expecting it to work. Same error on deploy as always:

But lo and behold, I can visit the site on heroku and the barcode scan is working....

I have no idea what to make of it. My buildpacks and ENV variables have been the same for the last several deploys.

Any thoughts? I can't make heads or tails of it.

[willglynn]

A-ha! The zbar gem is getting loaded in the slug compiler, and in that context the libzbar.so lives at a different path and environment variables work differently.

I'm guessing it's being loaded as part of rake assets:precompile, and I'd also guess it's not needed at all for asset compilation. Try excluding it from the :assets group, or making it require: false and load it only in the code that really does need it.

[andyweiss1982]

Finally! @michaelryu the require: false in the Gemfile and separately requiring in the controller is what did it for me.

Thank you so much @willglynn for seeing this through to the end.

Answering my own Stack Overflow question here in case anyone has the same problem in the future:
http://stackoverflow.com/questions/31812168/how-can-i-get-zbar-to-deploy-on-heroku

[sheck]

Hi guys! I was dealing with similar issues the past few weeks and spent a lot of time trying to get it working. I ended up creating a heroku buildpack that uses the patched version of Zbar. I also figured out how to get it running on CircleCI. Maybe it will help someone else in the future!

Heroku:
https://github.com/sheck/heroku-buildpack-zbar

Circle CI:
https://gist.github.com/sheck/475e0c8f2d9f618f1eca