class Chef::Mixin::Template::TemplateContext
TemplateContext¶ ↑
TemplateContext is the base context class for all templates in Chef. It defines user-facing extensions to the base Erubis::Context to provide enhanced features. Individual instances of TemplateContext can be extended to add logic to a specific template.
Attributes
Public Class Methods
# File lib/chef/mixin/template.rb, line 59 def initialize(variables) super @_extension_modules = [] end
Public Instance Methods
# File lib/chef/mixin/template.rb, line 150 def _extend_modules(module_names) module_names.each do |mod| context_methods = [:node, :render, :render_template, :render_template_from_string] context_methods.each do |core_method| if mod.method_defined?(core_method) or mod.private_method_defined?(core_method) Chef::Log.warn("Core template method `#{core_method}' overridden by extension module #{mod}") end end extend(mod) @_extension_modules << mod end end
Collects instance variables set on the current object as a Hash suitable for creating a new TemplateContext. Instance variables that are only valid for this specific instance are omitted from the collection.
# File lib/chef/mixin/template.rb, line 167 def _public_instance_variables all_ivars = instance_variables all_ivars.delete(:@_extension_modules) all_ivars.inject({}) do |ivar_map, ivar_symbol_name| value = instance_variable_get(ivar_symbol_name) name_without_at = ivar_symbol_name.to_s[1..-1].to_sym ivar_map[name_without_at] = value ivar_map end end
INTERNAL PUBLIC API
# File lib/chef/mixin/template.rb, line 123 def _render_template(template, context) begin eruby = Erubis::Eruby.new(template) output = eruby.evaluate(context) rescue Object => e raise TemplateError.new(e, template, context) end # CHEF-4399 # Erubis always emits unix line endings during template # rendering. Chef used to convert line endings to the # original line endings in the template. However this # created problems in cases when cookbook developer is # coding the cookbook on windows but using it on non-windows # platforms. # The safest solution is to make sure that native to the # platform we are running on is used in order to minimize # potential issues for the applications that will consume # this template. if Chef::Platform.windows? output = output.gsub(/\r?\n/,"\r\n") end output end
Returns the current node object, or raises an error if it's not set. Provides API consistency, allowing users to reference the node object by the bare `node` everywhere.
# File lib/chef/mixin/template.rb, line 71 def node return @node if @node raise "Could not find a value for node. If you are explicitly setting variables in a template, " + "include a node variable if you plan to use it." end
Takes the name of the partial, plus a hash of options. Returns a string that contains the result of the evaluation of the partial.
All variables from the parent template will be propagated down to the
partial, unless you pass the variables
option (see below).
Valid options are:
- :local
-
If true then the partial name will be interpreted as the path to a file on the local filesystem; if false (the default) it will be looked up in the cookbook according to the normal rules for templates.
- :source
-
If specified then the partial will be looked up with this name or path (according to the
local
option) instead ofpartial_name
. - :cookbook
-
Search for the partial in the provided cookbook instead of the cookbook that contains the top-level template.
- :variables
-
A Hash of variable_name => value that will be made available to the partial. If specified, none of the variables from the master template will be, so if you need them you will need to propagate them explicitly.
# File lib/chef/mixin/template.rb, line 100 def render(partial_name, options = {}) raise "You cannot render partials in this context" unless @template_finder partial_variables = options.delete(:variables) || _public_instance_variables partial_context = self.class.new(partial_variables) partial_context._extend_modules(@_extension_modules) template_location = @template_finder.find(partial_name, options) _render_template(Mixin::Template.binread(template_location), partial_context) end
# File lib/chef/mixin/template.rb, line 111 def render_template(template_location) _render_template(Mixin::Template.binread(template_location), self) end
# File lib/chef/mixin/template.rb, line 115 def render_template_from_string(template) _render_template(template, self) end