In this blog post he gives this example of a Ruby config file.
config do
allow ['server.com', `hostname`.strip]
vhost 'api.server.com' do
path ‘/usr/local/api’
end
vhost 'www.server.com' do
path '/usr/local/web'
end
%w{wiki blog support}.each do |host|
vhost "#{host}.server.com" do
path "/usr/local/#{host}"
end
end
end
I think of a hash after a config file have been loaded, but maybe that is not how this type of configs are intended for...
Update
If I execute it, I get
$ ruby config.rb
config.rb:2:in `<main>': undefined method `config' for main:Object (NoMethodError)
Question
What Ruby code is needed to parse and dump the content of this config file?
That config example is not directly loadable and, if I understand the blog post author correctly, it's not meant to be either so there's no easy way of loading/parsing that example.
The key part is in the blog post where he states "build simple DSLs to design semantically robust config files without the underlying ruby being conspicuous" (my emphasis). The 'underlying ruby' I take to mean the code that enables the DSL elements you're seeing such as 'config' and 'vhost'.
Your original question was, however, what code is required to load that config - below is a sample of something would work, full implementation is up to you and tbh I'm pretty sure there are cleaner, "better" ways of doing the same.
class AppConfig
attr_accessor :hosts
def allow(hosts)
#hosts = hosts
end
def vhost(hostname)
end
def process_config(&block)
instance_eval(&block)
end
end
def config(&block)
config = AppConfig.new
config.process_config &block
puts "Hosts are: #{config.hosts}"
end
load 'config.rb'
Related
I'm building a Ruby gem that includes a module that's meant to monkey-patch the Hash class to add a new method. I'm following this guide to try to do it neatly: http://www.justinweiss.com/articles/3-ways-to-monkey-patch-without-making-a-mess/
I've placed the module in lib/core_extensions/hash/prune.rb, and the module is declared as such:
module CoreExtensions
module Hash
module Prune
##
# Removes all pairs from the Hash for which the value is nil. Destructive!
def prune!
self.reject! { |_, v| v.nil? }
end
end
end
end
And in order to make the monkey patch take effect, I'm calling this within the main gem file:
Hash.include(CoreExtensions::Hash::Prune)
But after building the gem and trying to require it in an irb console, I get the following error: NameError: uninitialized constant Gem::CoreExtensions (Gem is a placeholder name).
I made sure to include the prune.rb file in my gemspec's files array: s.files = ['lib/gem.rb', 'lib/core_extensions/hash/prune.rb'], so I'm not sure why it can't detect the file and its modules. Can anyone help me figure this out?
Thank you!
EDIT: In case it will help anyone else - I tried to require the module file using require 'lib/core_extensions/hash/prune' but received 'cannot load such file' errors. Sticking ./ in front of the path fixed it.
I have a class that laod config file from config/config.yml.
class Example
def initialize
config = YAML.load_file('config/config.yml')
end
end
I have created proyect/spec/config/config.yml example file but when I run the test it try load file proyect/config/config.yml.
How I change rspec working directory?
Why not point the config to the right path?
class Example
def initialize
config = YAML.load_file('spec/config/config.yml')
end
end
According to this, you can set the load_path like so
$LOAD_PATH.unshift 'spec'
or
$:.unshift 'spec'
Also according to that,
As much as I like removing unnecessary requires in specs I prefer verbosity over magic -- anything that gives the code reader more clarity as to what's necessary for a particular example group.
I'm currently working on a script (command line tool) for work to help me manage expose consoles.
At first I was passing three arguments to the script each time I used it to login into the consoles, for example:
$ nexose-magic.rb -u user -p password -i 192.168.1.2 --display-scans
It's not very efficient, so I created a config.yml file that stores console information in a hash.
$ nexpose-magic.rb -c console --display-scans
I believe the tool will be useful to admins out there, so I'd like to share it in a gem. I can't figure out how to get my config.yml file to work with a gem install..It can't find the config.yml file! It's easy to point it at the relative path in my development directory, but once I create a gem that relative path isn't so relative anymore. How do I point nexpose-magic.rb at the config.yml file?
Is there a better way to handle something like this?
You can create a gem that include a configure class. This class has a load method that will take a directory as an argument. Then, you can pass the directory where you are currently working.
A nice way of preparing your gem is to create a Configuration singleton class in your gem:
require 'singleton'
class Configuration
include Singleton
attr_accessor :config, :app_path
def load(app_path)
#app_path = app_path
#load the config file and store the data
#config = YAML.load_file( File.join(#app_path,'config','config.yml'))
end
end
In your main class :
module MyFancyGem
class << self
#define a class method that configure the gem
def configure(app_path)
# Call load method with given path
config.load(app_path)
end
# MyFancyGem.config will refer to the singleton Configuration class
def config
MyFancyGem::Configuration.instance
end
end
end
Usage:
-Working directory
- my_new_script
- Gemfile
- config/
- config.yml
In my_new_script :
require 'bundler'
Bundler.setup(:default)
require 'my_fancy_gem'
MyFancyGem.configure(File.join(File.dirname(__FILE__),"./")) #here, you define the path
MyFancyGem.hello_world
I hope that's clear enough. I was actually about to write a blog post to explain this particular point (I hope in a more complete version of it). Let me know if you're interested !
Is there anyway to get Ruby's require statement to download a file from somewhere like github rather than just the local file system?
Update: Sorry I should have made the question clearer. I want to download a file that contains Ruby module and import it into my script rather than just downloading an image or some other arbitrary file within my script.
In other words something like this
require 'http:\\github.com\myrepo\snippet.rb'
puts 'hi'
By default, this is not possible. Also, it's not a good idea for security reasons.
You have a couple of alternatives. If the file you want to include is a Gem and Git repository, then you can use Bundler to download and package the dependency in your project. Then you'll be able to require the file directly in your source code.
This is the best and safest way to include an external dependency.
If you trust the source and you really know what you are doing, you can download the file using Net::HTTP (or any other HTTP library) and eval the body directly in your Ruby code.
You can package everything in a custom require_remote function.
You could download and eval it
require "open-uri"
alias :require_old :require
def require(path)
return false if $".include?(path)
unless path=~ /\Ahttp:\/\/
return require_old(path)
end
eval(open(path).read)
$"<< path
true
end
Be aware, this code has no error checking for network outages nonexisting files, ... . I also believe it is in general not a good idea to require libraries this way, there are security and reliability problems in this approach. But maybe you have a valid usecase for this.
you can include a remote gem from within Gemfiles then it will download when you run bundle install
After reading this question and answers I wanted something a little more bullet proof and verbose that used a paradigm of creating a local file from a repo and then requiring it, only if it didn't already exist locally already. The request for the repo version is explicit via the method repo_require. Used on files you control, this approach improves security IMO.
# try local load
def local_require(filename, relative_path)
relative_flname = File.join(relative_path, filename)
require_relative(relative_flname)
end
# try loading locally first, try repo version on load error
# caution: only use with files you control access to!
def repo_require(raw_repo_prefix, filename, relative_path = '')
local_require(filename, relative_path)
rescue LoadError => e
puts e.message
require 'open-uri'
tempdir = Dir.mktmpdir("repo_require-")
temp_flname = File.join(tempdir, File.basename(filename))
return false if $LOADED_FEATURES.include?(temp_flname)
remote_flname = File.join(raw_repo_prefix, filename)
puts "file not found locally, checking repo: #{remote_flname}"
begin
File.open(temp_flname, 'w') do |f|
f.write(URI.parse(remote_flname).read)
end
rescue OpenURI::HTTPError => e
raise "Error: Can't load #{filename} from repo: #{e.message} - #{remote_flname}"
end
require(temp_flname)
FileUtils.remove_entry(tempdir)
end
Then you could call repo_require like this:
repo_require('https://raw.githubusercontent.com/username/reponame/branch',
'filename', 'relative_path')
The relative_path would the the relative path you would use for the file if the repo was locally installed. For example, you may have something like require_relative '../lib/utils.rb'. In this example filename='lib/utils.rb' and relative_path='..'. This information allows the repo url to be constructed correctly as it does not use the relative path portion.
I've found the method set_log in the documentation, I just can't figure out the syntax to call it. Here's what I tried:
require 'ruby-aws'
Amazon::Util::Logging.set_log('my.log')
NoMethodError: undefined method `set_log' for Amazon::Util::Logging:Module
You can see that Amazon::Util::Logging is a module and set_log is a 'Public Instance method'. So you need
class NewClass
include Amazon::Util::Logging
def foo
set_log('file.txt')
log 'debug_message'
end
end
I ran into this problem when trying to deploy a Ruby-on-Rails site that uses 'aws-ruby' to heroku (I got the "Permission denied - ruby-aws.log" error).
To change the log file location from 'ruby-aws.log' to 'log/ruby-aws.log', I added the following to an initializer. Make sure this is called before you use any of the aws-ruby library. Notice the change on the "set_log..." line.
module Amazon
module Util
module Logging
def log( str )
set_log 'log/ruby-aws.log' if ##AmazonLogger.nil?
##AmazonLogger.debug str
end
end
end
end
A simpler way would be to add this line:
set_log("/dev/null")