Output to a file instead of stdoutbtm/knife-yaml

Refactor and direct output to a file with some magic to make up a good
output filename.

Signed-off-by: Bryan McLellan <btm@loftninjas.org>

2 files changed, 52 insertions, 20 deletions

diff --git a/lib/chef/knife/core/ui.rb b/lib/chef/knife/core/ui.rb
index 03b11a1b4d..893daa04e9 100644
--- a/lib/chef/knife/core/ui.rb
+++ b/lib/chef/knife/core/ui.rb
@@ -140,6 +140,14 @@ class Chef
         log("#{color("FATAL:", :red, :bold)} #{message}")
       end
 
+      # Print a message describing a fatal error and exit 1
+      #
+      # @param message [String] the text string
+      def fatal!(message)
+        fatal(message)
+        exit 1
+      end
+
       def color(string, *colors)
         if color?
           pastel.decorate(string, *colors)
diff --git a/lib/chef/knife/yaml_convert.rb b/lib/chef/knife/yaml_convert.rb
index 5cdc340d22..a5b75e5691 100644
--- a/lib/chef/knife/yaml_convert.rb
+++ b/lib/chef/knife/yaml_convert.rb
@@ -20,48 +20,72 @@ require "yaml"
 require_relative "../knife"
 class Chef::Knife::YamlConvert < Chef::Knife
 
-  banner "knife yaml convert YAML_FILENAME"
+  banner "knife yaml convert YAML_FILENAME [RUBY_FILENAME]"
 
   def run
     if name_args.empty?
-      ui.error("Please specify the file name of a YAML recipe to convert to Ruby")
-      exit 1
-    elsif name_args.size >= 2
-      ui.error("Only one recipe may converted at a time")
-      exit 1
+      ui.fatal!("Please specify the file name of a YAML recipe to convert to Ruby")
+    elsif name_args.size >= 3
+      ui.fatal!("knife yaml convert YAML_FILENAME [RUBY_FILENAME]")
     end
 
-    filename = @name_args[0]
-    yaml_contents = IO.read(filename)
+    yaml_file = @name_args[0]
+    unless ::File.exist?(yaml_file) && ::File.readable?(yaml_file)
+      ui.fatal("Input YAML file '#{yaml_file}' does not exist or is unreadable")
+    end
+
+    ruby_file = if @name_args[1]
+                  @name_args[1] # use the specified output filename if provided
+                else
+                  if ::File.extname(yaml_file) == ".yml" || ::File.extname(yaml_file) == ".yaml"
+                    yaml_file.gsub(/\.(yml|yaml)$/, ".rb")
+                  else
+                    yaml_file + ".rb" # fall back to putting .rb on the end of whatever the yaml file was named
+                  end
+                end
+
+    if ::File.exist?(ruby_file)
+      ui.fatal!("Output Ruby file '#{ruby_file}' already exists")
+    end
+
+    yaml_contents = IO.read(yaml_file)
 
+    # YAML can contain multiple documents (--- is the separator), let's not support that.
     if ::YAML.load_stream(yaml_contents).length > 1
-      raise ArgumentError, "YAML recipe '#{filename}' contains multiple documents, only one is supported"
+      ui.fatal!("YAML recipe '#{yaml_file}' contains multiple documents, only one is supported")
     end
 
     # Unfortunately, per the YAML spec, comments are stripped when we load, so we lose them on conversion
     yaml_hash = ::YAML.safe_load(yaml_contents)
     unless yaml_hash.is_a?(Hash) && yaml_hash.key?("resources")
-      raise ArgumentError, "YAML recipe '#{source_file}' must contain a top-level 'resources' hash (YAML sequence), i.e. 'resources:'"
+      ui.fatal!("YAML recipe '#{source_file}' must contain a top-level 'resources' hash (YAML sequence), i.e. 'resources:'")
     end
 
+    ui.warn("No resources found in '#{yaml_file}'") if yaml_hash["resources"].size == 0
+
+    ::File.open(ruby_file, "w") do |file|
+      file.write(resource_hash_to_string(yaml_hash["resources"], yaml_file))
+    end
+    ui.info("Converted '#{yaml_file}' to '#{ruby_file}'")
+  end
+
+  # Converts a Hash of resources to a Ruby recipe
+  # returns a string ready to be written to a file or stdout
+  def resource_hash_to_string(resource_hash, filename)
     ruby_contents = []
-    ruby_contents << "# Autoconverted recipe from #{filename}"
-    ruby_contents << ""
+    ruby_contents << "# Autoconverted recipe from #{filename}\n"
 
-    yaml_hash["resources"].each do |r|
+    resource_hash.each do |r|
       type = r.delete("type")
       name = r.delete("name")
 
       ruby_contents << "#{type} \"#{name}\" do"
-      r.each do |p|
-        ruby_contents << "  #{p.shift} \"#{p.shift}\""
+      r.each do |k, v|
+        ruby_contents << "  #{k} \"#{v}\""
       end
-      ruby_contents << "end"
-      ruby_contents << ""
+      ruby_contents << "end\n"
     end
 
-    ruby_contents.each do |l|
-      puts l
-    end
+    ruby_contents.join("\n")
   end
 end