In our Rails application we do require 'RRD' at some point, but that results in a cannot load such file -- RRD. So obviously I used homebrew to install rrdtool, but the error remains.
The docs at https://oss.oetiker.ch/rrdtool/prog/rrdruby.en.html provide two options:
Either:
$: << '/path/to/rrdtool/lib/ruby/1.8/i386-linux'
require "RRD"
In my /opt/homebrew/Cellar/rrdtool/1.8.0/lib directory there's no mention of ruby, which is because of the --disable-ruby-site-install flag in the formula, because when I skip that flag I do actually get something: /opt/homebrew/Cellar/rrdtool/1.8.0/lib/ruby/2.6.0/universal-darwin21. However replacing the path/to string with this path still gives the error.
Or:
If you use the --ruby-site-install configure option you can drop the $: line since the RRDtool module will be found automatically.
Which is a little confusing (and probably outdated) because here it seems that ruby site install is disabled by default and you have to enable it proactively, whereas in the formula it's actually actively disabled.
Either way: both options didn't do the trick for me and if there's a solution without homebrew that's also fine.
For good measure: I'm on macOS Monterey
TL;DR
For the most part, I'd say that using a non-standard gem without a Ruby version manager is your main issue. There are instructions on the rrdruby site for installing it, but they don't follow typical conventions, so your mileage will vary.
Some Practical Suggestions
The require keyword is for gems, not binaries. You need to have an rrdtool-related gem installed, available to your Ruby instance (usually through a Bundler Gemfile or gemspec, or via the RUBYOPTS environment variable or your in-process Ruby $LOAD_PATH), and then require the correct name of the gem in your code. For example, using the older rrd-ffi gem:
# use sudo if you're installing it to the system,
# but I would strongly recommend a ruby version
# manager instead
gem install rrd-ffi
# in your Ruby class/module file
require "rrd"
For the gem you seem to be using, you have to compile the gem first to make it usable, and then ensure it's available in your Ruby $LOAD_PATH (or other gem lookup mechanism) before trying to require it. The error message you're seeing is basically telling you that a gem with that name is not available as called within any of the standard lookup locations.
Again, I'd suggest reading the build documentation for your gem, and then seeing if you can install it as part of a Bundler bundle, RVM gemset, or other non-system approach if you can. Otherwise, follow the directions for the rrdruby tool, which is not available as a standard Rubygems.org gem, in order to make it available before trying to require it.
Beware of Outdated or Non-Standard Gems
Most of the RRD gems I found were quite old; most were 7-8 years old or older, so their compatibility with current Rubies is potentially suspect. The gem-builder you're using is newer, but doesn't seem to be designed as a standard gem, so you need to build it and install it in a suitable lookup path before it can be required. Installing gems as system gems is almost always a bad idea, so I'd strongly recommend building it from source and using a ruby version manager rather than following the rrdtool author's atypical suggestions. YMMV.
I can gem open #{gem_name} (command line) to see the source of installed gems. But how do I view the source of e.g. openssl which is in ruby core?
(Without going to the github repo... is there a command to view it locally?)
There isn't one. The reason most probably is that gems shipped with Ruby aren't treated in a different way than the core code. That said, the libraries are located under ext/.
If you want to find specific code (assuming it's Ruby and not C), you can always do
foo.method(:bar).source_location
Foo.instance_method(:bar).source_location
I want my app to not be able to use any installed gems. Is there a ruby 1.9 startup parameter or way of doing this programmatically?
ruby --disable-gems
is the MRI (1.9) commandline parameter. "It prevents the addition of gem installation directories to the default load path". (The Ruby Programming Language, p. 391)
Edit 25-10-2012: Ruby core had the same idea as #rogerdpack in the comments and added the more verbose ruby --help parameter. Ruby revision!
Looking at the rubygems configuration file, I would attempt to hack out gempath or gemhome to see if you can override (instead of just append to) defaults.
If, for example, setting gempath to be empty, or to point to /dev/null, prevents using system gems, then that would be the way to go.
The main advantage to this, as I see it, is that your anti-rubygems config file can be passed to ruby 1.9 as a startup parameter (so not coded in), well documented, and checked into your repository.
All of this is, of course, disregarding that rubygems is part of ruby 1.9's standard library - so ruby may choke and die if it can't have access to its gems, depending on how much of ruby's base install requires gem functionality. YMMV.
Quite often Ruby installed with RVM (the 'most popular tool to install Ruby') produces a binary not capable of SSL operations (like connecting via HTTPS). It's a known issue with a known workaround.
If you're trying to use SSL with such Ruby binary it results in exception LoadError: cannot load such file -- openssl.
Question: is there any way I can tell which libs Ruby binary was built against and thus detect if it is capable of SSL or not at runtime? Other than trying to actually use SSL and catching the exception?
Unless you want to do the same work that require does, I think the easiest is to try to require openssl and rescue the LoadError in case it's not present on the system to detect its availability.
It seems to be an idiom commonly used.
If you wanted something that detects afterwards if it was loaded or not would
ruby -ropenssl -e 'p defined? OpenSSL' # => "constant"
vs.
ruby -e 'p defined? OpenSSL' # => nil
help you?
That is, checking whether the return value of defined?(OpenSSL) is non-nil?
We commonly use this in tests to exclude tests at runtime where features that are not available to all versions of OpenSSL are used, and to exclude tests completely (if defined? OpenSSL) if OpenSSL is not present as an extension.
I'm trying to install some Ruby Gems so I can use Ruby to notify me when I get twitter messages. However, after doing a gem update --system, I now get a zlib error every time I try and do a gem install of anything. below is the console output I get when trying to install ruby gems. (along with the output from gem environment).
C:\data\ruby>gem install twitter
ERROR: While executing gem ... (Zlib::BufError)
buffer error
C:\data\ruby>gem update --system
Updating RubyGems
ERROR: While executing gem ... (Zlib::BufError)
buffer error
C:\data\ruby>gem environment
RubyGems Environment:
- RUBYGEMS VERSION: 1.2.0
- RUBY VERSION: 1.8.6 (2007-03-13 patchlevel 0) [i386-mswin32]
- INSTALLATION DIRECTORY: c:/ruby/lib/ruby/gems/1.8
- RUBY EXECUTABLE: c:/ruby/bin/ruby.exe
- EXECUTABLE DIRECTORY: c:/ruby/bin
- RUBYGEMS PLATFORMS:
- ruby
- x86-mswin32-60
- GEM PATHS:
- c:/ruby/lib/ruby/gems/1.8
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :benchmark => false
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- http://gems.rubyforge.org/
Found it! I had the same problem on windows (it appeared suddenly without me doing an update, but whatever):
It has something to do with multiple conflicting zlib versions (I think).
In ruby/lib/ruby/1.8/i386-msvcrt, make sure that there exists a zlib.so file. In my case, it was already there. If not, you may try to install ruby-zlib.
Then go to ruby/lib/ruby/site_ruby/1.8./i386-msvcrt and delete the zlib.so file there.
In ruby/bin, there should be a zlib1.dll. For some reason my Ruby version did not use this dll. I downloaded the most recent version (1.2.3) and installed it there. I had to rename it to zlib.dll for it to be used.
And tada! Rubygems worked again.
Hope this helps.
Firstly, I thank the person, who came up with the solution to the missing zlib problem. (It wasn't me. :-)
Unfortunately I lost the link to the original posting, but the essence of the solution on Linux is to compile the Ruby while zlib header files are available to the Ruby configure script. On Debian it means that zlib development packages have to be installed before one starts to compile the Ruby.
The rest of my text here does not contain anything new and it is encouraged to omit it, if You feel comfortable at customizing Your execution environment at UNIX-like operating systems. The following is a combination of a brief intro to some basics and step by step instructions.
------The-start-of-the-HOW-TO-------------------------
If one wants to execute a program, let's say, irb, from a console, then the file named irb is searched from folders in an order that is described by an environment variable called PATH. It's possible to see the value of the PATH by typing to a bash shell (and pressing Enter key):
echo $PATH
For example, if there are 2 versions of irb in the system, one installed by the "official" package management system, let's say, yum or apt-get, to /usr/bin/irb and the other one that is compiled by the user named scoobydoo and resides in /home/scoobydoo/ourcompiledruby/bin then the question arises, which one of the two irb-s gets executed.
If one writes to the
/home/scoobydoo/.bashrc
a line like:
export PATH="/home/scoobydoo/ourcompiledruby/bin:/usr/bin"
and restarts the bash shell by closing the terminal window and opening a new one, then by typing irb to the console, the
/home/scoobydoo/ourcompiledruby/bin/irb gets executed. If one wrote
export PATH="/usr/bin:/home/scoobydoo/ourcompiledruby/bin"
to the
/home/scoobydoo/.bashrc
,then the /usr/bin/irb would get executed.
In practice one wants to write
export PATH="/home/scoobydoo/ourcompiledruby/bin:$PATH"
because this prepends all of the values that the PATH had prior to this assignment to the /home/scoobydoo/ourcompiledruby/bin. Otherwise there will be problems, because not all common tools reside in the /usr/bin and one probably wants to have multiple custom-built applications in use.
The same logic applies to libraries, except that the name of the environment variable is LD_LIBRARY_PATH
The use of the LD_LIBRARY_PATH and PATH allow ordinary users, who do not have root access or who want to experiment with not-that-trusted software, to build them and use them without needing any root privileges.
The rest of this mini-how-to assumes that we'll be building our own version of ruby and use our own version of it almost regardless of what is installed on the system by the distribution's official package management software.
1)=============================
First, one creates a few folders and set the environment variables, so that the folders are "useful".
mkdir /home/scoobydoo/ourcompiledruby
mkdir -p /home/scoobydoo/lib/our_gems
One adds the following 2 lines to the
/home/scoobydoo/.bashrc
export PATH="/home/scoobydoo/ourcompiledruby/bin:$PATH"
export GEM_HOME="/home/scoobydoo/lib/our_gems"
Restart the bash shell by closing the current terminal window and opening a new one or by typing
bash
on the command line of the currently open window.
The changes to the /home/scoobydoo/.bashrc do not have any effect on terminal windows/sessions that were started prior to the saving of the modified version of the /home/scoobydoo/.bashrc
The idea is that the /home/scoobydoo/.bashrc is executed automatically at the start of a session, even if one logs on over ssh.
2)=============================
Now one makes sure that the zlib development packages are available on the system. As of April 2011 I haven't sorted the details of it out, but
apt-get install zlibc zlib1g-dev zlib1g
seems to be sufficient on a Debian system. The idea is that both, the library file and header files, are available in the system's "official" search path. Usually apt-get and alike place the header files to the /usr/include and library files to the /usr/lib
3)=============================
Download and unpack the source tar.gz from the http://www.ruby-lang.org
./configure --prefix=/home/scoobydoo/ourcompiledruby
make
make install
4)=============================
If a console command like
which ruby
prints to the console
/home/scoobydoo/ourcompiledruby/bin/ruby
then the newly compiled version is the one that gets executed on the command
ruby --help
5)=============================
The rest of the programs, gem, irb, etc., can be properly executed by using commands like:
ruby `which gem` install rake
ruby `which irb`
It shouldn't be like that but as of April 2011 I haven't figured out any more elegant ways of doing it. If the
ruby `which gem` install rake
gives the zlib missing error again, then one should just try to figure out, how to make the zlib include files and library available to the Ruby configure script and recompile. (Sorry, currently I don't have a better solution to offer.)
May be a dirty solution might be to add the following lines to the
/home/scoobydoo/.bashrc
alias gem="`which ruby` `which gem` "
alias irb="`which ruby` `which irb` "
Actually, I usually use
alias irb="`which ruby` -KU "
but the gem should be executed without giving the ruby the "-KU" args, because otherwise there will be errors.
------The-end-of-the-HOW-TO------------------------
I just started getting this tonight as well. Googling turned up a bunch of suggestions that didn't deliver results
gem update --system
and some paste in code from jamis that is supposed to replace a function in package.rb but the original it is supposed to replace is nowhere to be found.
Reinstalling rubygems didn't help. I'm reinstalling ruby right now.........and it is fixed. Pain though.
How about cd into rubysrc/ext/zlib, then ruby extendconf.rb, then make, make install.
After do that, reinstall ruby.
I did this on ubuntu 10.04 and was successful.
A reinstall of Ruby sorted this issue out. It's not what I wanted; I wanted to know why I was getting the issue, but it's all sorted out.
It most often shows up when your download failed -- i.e. you have a corrupt gem, due to network timeout, faulty manual download, or whatever. Just try again, or download gems manually and point gem at the files.
if gem update --system not works and rename ruby/bin/zlib1.dll to zlib.dll not helps try:
Open file RUBY_DIR\lib\ruby\site_ruby\1.8\rubygems.rb
And replace existed def self.gunzip(data) by this:
def self.gunzip(data)
require 'stringio'
require 'zlib'
data = StringIO.new data
# Zlib::GzipReader.new(data).read
data.read(10) # skip the gzip header
zis = Zlib::Inflate.new(-Zlib::MAX_WBITS)
is = StringIO.new(zis.inflate(data.read))
end
Try updating ZLib before you do anything else. I had a similar problem on OS X and updating Compress::Zlib (a Perl interface to ZLib) cured it - so I think an old version of ZLib (is now 1.2.3) may be where your problem lies...
install pure ruby zlib if all else fails