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
Related
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Which is a little confusing (and probably outdated) because here it seems that ruby site install is disabled by default and you have to enable it proactively, whereas in the formula it's actually actively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 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.
With Jeweler I created a gem folder structure with ease.
However, I still have some questions:
Why are params like --gemcutter and --rubyforge still available for Jeweler. Aren't these replaced by RubyGems? Do I have to specify anything to create a gem for RubyGems?
In the Rakefile I have information about the gem, and when I run "rake install" it created a gemspec. Why is the same information in two places?
What is a manifest? Just read about it, haven't seen such file.
How do I make my gem callable from the shell once I have installed it, like rails. Cause right now it's just accessible through a Ruby script using require.
Should I use "jeweler release" or "gem push" to push my gem to RubyGems.org?
I have to specify "handle" when signing up in RubyGems. What is that?
Thanks.
jeweler was created before RubyGems became what it is, so it still reflects the split. I'm not sure when jeweler was last updated, either. (I think it also still recognizes building gems on Github, which is now disabled.)
I'm not sure I follow what you're saying. The specification in the Rakefile details what the spec that gets written should look like. The spec that gets written details what should be installed and how, I believe.
A manifest is a list of all the files that your gem should ship with. Not everyone uses one. See the hoe documentation for some pro-manifest discussion.
Many Ruby gems are only libraries. If you want yours to also have a program like jeweler or rake or rails that you can call, you have to write the callable program, put it in bin in your gem's layout and specify (in your gemspec) that it should be packaged and installed. See the Gem::Specification reference under files and executable.
Not sure. Consult both jeweler's docs and the docs for RubyGems.
You can give an email address or use a name (a 'handle', like I use Telemachus here), which is all they mean by 'handle'.
For the record, if you are just learning how to write gems, you do not need to upload your first attempts using RubyGems or anything like it. You can simply install the gem on your machine only.
I am trying to hack through a forked gem (buildr). As such I cloned it from github and began to butcher the code. The official gem is installed on my system (under /usr/lib/ruby.../gems/buildr...). There is an executable which I need to use in my dev process - buildr.
Now I want the buildr executable and the library to point to my forked repo and not the default gem installation. This would be for this gem only. As such, the changes I make against the forked repo is usable directly for testing and so forth.
I would guess I need to load my library prior to the system gem loading. Can somebody recommend the best way to do so?
I did something similar for work when the Spreadsheet gem broke backward compatibility. I put the previous versions code in it's own module and just renamed the gem my-spreadsheet and installed that (I really wanted some of the features of the new gem but I also didn't want to rewrite all my previous code at that point).
If it's just a binary you want to override you could always do some PATH magic, setting the directory of your binary first and thus make sure you always override. But personally I'd prefer making my own copy with a new name and installing that.
you could bump the version in the gemspec for your fork. Then when you install your version of the gem, it will use your (newer) version by default.
change buildr.gemspec
#...
spec.version = '1.3.4.dev'
#...
Then
$ gem build buildr.gemspec
$ sudo gem install buildr-1.3.4.dev.gem
and it should work.
I am trying to set up Ruby on Rails on windows. I am using the Flash Rails distribution that looks pretty good, but there is an issue with sqlite3. I found the threads telling me to install version 1.2.3, which installed fine. I'm using ruby 1.9.0, and every time I try and run a script (e.g. rake db:create) that uses the database I get an error message "no driver for sqlite3 found".
This apparently is a missing sqlite3.dll, but I have the dll in my %PATH%, and I have also tried copying it into the directory where I am running the script from, the directory where the sqlite3 ruby code lives.
Does anyone have any ideas? If possible I want all teh ruby stuff to be self contained so I can use it from a pen drive.
EDIT: To clarify, I already used gem install to install the ruby-sqlite3 gem - it is just non functional as it cannot find the sqlite3.dll (even though it is actually present in a directory on my %PATH%)
EDIT PART 2: After doing some more digging, the problem appears that ruby will not load the sqlite3_api.dll. I have copied it all over my filesystem, I just get a failure to read file. Other dll libraries in the same directory (e.g. zlib.dll) work fine!
I tried installing the dlls into system32, and that did not work either.
The problem put simply is that sqlite3-ruby 1.2.3 is not compatible with ruby 1.9. This is caused because ruby 1.9 does not use .dll files for c libraries it uses .so files instead. Additionally, since sqlite3_api.dll is written against msvcrt-ruby18.dll. This means that it specifically only will support ruby 1.8.*.
The good news is that there is a fat binary version that will support both ruby 1.8 and ruby 1.9. Uninstalling all former versions of sqlite3-ruby and then installing this one. (You may have to manually delete some versions the gem after uninstalling.) in order to install it use
install sqlite3-ruby --source http://gems.rubyinstaller.org
for more information see this website
Try installing the sqlite3-ruby gem:
gem install sqlite3-ruby
Something similar happened to me recently so I thought I'd update my answer.
For reference there's a sqlite3_api.dll file located in the gem's lib directory. Also the sqlite3.dll file needs to be reachable on the path. They are different files, the first is required by the gem to interface Ruby to C code, while the second contains the actual Sqlite implementation.
It's best to get the second file from the sqlite website and extract it to the Ruby\bin directory (as you shouldn't manually put DLL's into the windows or windows\system directories any more).
So for reference "sqlite3_api.dll" needs to be in:
Ruby\lib\ruby\gems\1.8\gems\sqlite3-ruby-1.2.3-x86-mswin32\lib
and "sqlite3.dll" needs to be on the path, possibly in:
Ruby\bin
As for the "driver not found" problem I would suggest trying the easy things first and making sure gems is installed correctly, up to date, and that the RUBYLIB and PATH environment variables are set appropriately. (System restart may be required to propagate the changes fully.)
Re this link
Download sqlitedll-3_6_10.zip and extract into ruby/bin!
Try going to sqlite.org download page and get the zipped up dll. Then put that in your c:\windows\system32 folder, that should allow Ruby to find it.
Restart your machine after running install sqlite3-ruby
To clarify, which gem are you using? sqlite-ruby or sqlite3-ruby?
They're part of the same project, but different releases. The key is that sqlite3 appears to have driver code included.
I assume you're attempting to use the first, since it's giving me the same error. If so, try switching.
Also.. How literal do you mean by this?
but I have the dll in my %PATH%
PATH=...;C:\sqlite\sqlite3.dll
PATH=...;C:\sqlite
The first will attempt to find C:\sqlite\sqlite3.dll\sqlite3.dll, AFAIK.
I use Ruby 1.8.7 (works with 1.9.1 too)
OS is WindowsXP SP3
Go to
http://www.sqlite.org/download.html
and Download file
sqlitedll-3_7_0_1.zip (265.19 KiB)
and unzip then we will get
sqlite3.dll
Copy sqlite3.dll to your bin folder
as C:\Ruby191\bin or C:\Ruby187\bin
then it works