# 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

_extension_modules[R]

### Public Class Methods

new(variables) click to toggle source
Calls superclass method

    # File lib/chef/mixin/template.rb, line 59
    def initialize(variables)
      super
      @_extension_modules = []
    end

### Public Instance Methods

_extend_modules(module_names) click to toggle source

    # 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

_public_instance_variables() click to toggle source

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

_render_template(template, context) click to toggle source

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

node() click to toggle source

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

render(partial_name, options = {}) click to toggle source

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 of `partial_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

render_template(template_location) click to toggle source

    # File lib/chef/mixin/template.rb, line 111
    def render_template(template_location)
      _render_template(Mixin::Template.binread(template_location), self)
    end

render_template_from_string(template) click to toggle source

    # File lib/chef/mixin/template.rb, line 115
    def render_template_from_string(template)
      _render_template(template, self)
    end