<pre><code>
# As an example here is the FileResolver
class WarningShot::FileResolver
include WarningShot::Resolver
# What is the add_dependency garbage? Where is require?
# All core libraries and gems should be 'required' with add_dependency, this allows warningshot to 'pick' it dependencies.
# This makes warningshot minimalistic. For example, if 'net/scp' was required for FileResolver (which it will in the future)
# you could still use warningshot without it, it would simply disable the use of scp_protocol resolution. By default
# if a dependency is missing warningshot will disable the whole Resolver (ie, fileutils and uri below). This is because they are
# critical in how the FileResolver works. The additional dependencies are optional based on how warningshot is being used.
add_dependency :core, 'fileutils'
add_dependency :core, 'uri'
add_dependency :core, 'net/http', :disable => false, :unregister => :http_protocol_resolver
add_dependency :core, 'net/https', :disable => false, :unregister => :https_protocol_resolver
# The default sequential order for the resolver to run in, this can be modified
# by the end user by FileResolver.order(1) or by specifying the order in
# the priority loader.
# WarningShot::Config.new({:pload => [:file]})
order 500
# The branch of the dependency tree to use, in the near future multiple branches will be
# able to be specified
branch :file
# A description of what the resolver does
description 'Validates presence of files'
# A resource needs to be created to 'stuff' the YAML into. Why?
# Because additional methods are added to track the status of tests and
# and resolution, so the dependency needs to be a mutable object.
FileResource = Struct.new(:source,:target) do
def exists?;File.exists?(File.expand_path(target.path));end;
def remove;File.unlink(File.expand_path(target.path));end;
end
# Resolver.typecast is what puts the YAML into the resource (above).
# typecast takes a class (optional) and a block multiple typecasts only need
# to be declared if there are multiple datatypes per dependency in the yaml file.
# FileResource can handle a String or a Hash. The class is optional, so if there is only
# one type of data in your yaml, you can leave it off
typecast String do |file|
FileResource.new URI.parse(''), URI.parse(file)
end
# Handling a hash from yaml
typecast Hash do |file|
file[:source].sub!(/file:\/\//i,'') unless file[:source].nil?
FileResource.new URI.parse(file[:source] || ''), URI.parse(file[:target])
end
# Resolver#initialize can be defined. It will be passed one arg and a variable list argument.
# Make sure to call super in the constructor
#
# there is also an attr_reader :config that will be available to the object
# and an attr_accessor :dependencies which stores the set of dependencies to be checked
def initialize(config,*deps)
super
end
# Multiple tests can be registered. The first test to pass the :if or :unless block (if provided)
# will be executed, if none pass it, then a default test will be run (one without a conditional block).
# Examples of conditional blocks can be seen in register :resolution below
#
# The actual test block (after do) can take 0, 1, or 2 arguments. The Resolver will pass in the correct number
# attributes. If one is specified it will pass in the current dependency (at runtime). If two are specified it will
# pass in the current dependency and the running configuration.
#
# @example
# #A test taking a file dependency and a configuration
# register(:test) do |file,config|
# if file.target.path =~ /database.yml/ && config[:environment] == 'production'
# # ... do some specific test for production database config files
# end
# end
#
# #A test with an :if conditional that takes the configuration...
# register(:test,:if => lambda{|file,config| config[:environment] == 'development' }) do |file|
# # ... the :if statement only allows this to run in the 'development' environment
# # ... in this test I may only need file and not the config.
# end
#
register :test, {:name => :file_check} do |file|
if file_found = file.exists?
logger.debug " ~ [PASSED] file: #{file.target.path}"
else
logger.warn " ~ [FAILED] file: #{file.target.path}"
end
file_found
end
# Register a resolution. The :if condition checks to see that the protocol to resolve over
# is file://
register(:resolution, { :name => :file_protocol,
:desc => "Resolves files from target sources",
:if => lambda { |file|
!!(file.source.scheme =~ /file/i || file.source.scheme == nil && !file.source.path.empty?)
}
}) do |file|
begin
FileUtils.cp File.expand_path(file.source.path), File.expand_path(file.target.path)
rescue Exception => ex
logger.error " ~ Could not restore file (#{file.target.path}) from #{file.source.path}"
end
file.exists?
end
# Register a resolution. The :if condition checks to see that the protocol to resolve over
# is http:// or https://
register(:resolution, { :name => :http_protocol,
:desc => "Resolves files from HTTP sources",
:if => lambda { |file| !!(file.source.to_s =~ /http(s)?/i)}
}) do |file|
begin
http = Net::HTTP.new(file.source.host,file.source.port)
http.use_ssl = (file.source.scheme == 'https')
file.source.path = '/' if file.source.path.empty?
resp = http.get(file.source.path)
File.open(file.target.path,"w+"){ |fs| fs.puts resp.body } if resp.code == "200"
rescue Exception => ex
logger.error " ~ Could not restore file (#{file.target.path}) from #{file.source.path}"
end
file.exists?
end
end
</code></pre>
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An example resolver
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