fetcher.rb in omnibus-4.0.0.beta.1

- old
+ new
@@ -12,176 +12,135 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
 
-require 'pp'
-
 module Omnibus
-  # Base class for classes that fetch project sources from the internet.
-  #
-  # @abstract Subclass and override the {#clean}, {#description},
-  #   {#fetch}, {#fetch_required?}, and {#version_guid} methods
-  #
-  # @todo Is this class supposed to be abstract or not?  Pretty sure
-  #   it's supposed to be abstract
   class Fetcher
-    # Given an error and a fetcher that generated the error, print a
-    # formatted report of the error and stacktrace, along with fetcher
-    # details to stderr.
+    include Digestable
+    include Logging
+    include Util
+
     #
-    # @note Does not rethrow the error; that must currently be done manually.
+    # The software for this fetcher.
     #
-    # @todo Since this is always called from within a fetcher, and
-    #   since the fetcher always passes itself in in the {#initialize}
-    #   method, this really ought to be encapsulated in a method call on
-    #   {Omnibus::Fetcher}.
-    # @todo Also, since we always 'raise' after calling {#explain}, we
-    #   should just go ahead and exit from here.  No need to raise,
-    #   since we're already outputting the real error and stacktrace
-    #   here.
-    class ErrorReporter
-      def initialize(error, fetcher)
-        @error, @fetcher = error, fetcher
-      end
-
-      # @todo Why not just make an attribute for error?
-      #
-      # @todo And for that matter, why not make an attribute for the
-      #   fetcher as well?  Or why not just use `@error` like we use
-      #   `@fetcher`?
-      def e
-        @error
-      end
-
-      # @todo If {Omnibus::Fetcher#description} is meant to show
-      #   parameters (presumably the kind of fetcher and the software it
-      #   is fetching?),
-      # @todo make this use the logger
-      def explain(why)
-        $stderr.puts '* ' * 40
-        $stderr.puts why
-        $stderr.puts 'Fetcher params:'
-        $stderr.puts indent(@fetcher.description, 2)
-        $stderr.puts 'Exception:'
-        $stderr.puts indent("#{e.class}: #{e.message.strip}", 2)
-        Array(e.backtrace).each { |l| $stderr.puts indent(l, 4) }
-        $stderr.puts '* ' * 40
-      end
-
-      private
-
-      # Indent each line of a string with `n` spaces.
-      #
-      # Splits the string at `\n` characters and then pads the left
-      # side with `n` spaces.  Rejoins them all again with `\n`.
-      #
-      # @param string [String] the string to indent
-      # @param n [Fixnum] the number of " " characters to indent each line.
-      # @return [String]
-      def indent(string, n)
-        string.split("\n").map { |l| ' '.rjust(n) << l }.join("\n")
-      end
-    end
-
-    class UnsupportedSourceLocation < ArgumentError
-    end
-
-    NULL_ARG = Object.new
-
-    # Returns an implementation of {Fetcher} that can retrieve the
-    # given software.
+    # @return [Software]
     #
-    # @param software [Omnibus::Software] the software the Fetcher should fetch
-    # @return [Omnibus::Fetcher]
-    def self.for(software)
-      if software.source
-        if software.source[:url] && Config.use_s3_caching
-          S3CacheFetcher.new(software)
-        else
-          without_caching_for(software)
-        end
-      else
-        Fetcher.new(software)
-      end
-    end
+    attr_reader :software
 
-    # @param software [Omnibus::Software] the software to fetch
-    # @raise [UnsupportedSourceLocation] if the software's source is not
-    #   one of `:url`, `:git`, or `:path`
-    # @see Omnibus::Software#source
-    # @todo Define an enumeration of the acceptable software types
-    # @todo This probably ought to be folded into {#for} method above.
-    #   It looks like this is called explicitly in
-    #   {Omnibus::S3Cache#fetch}, but that could be handled by having a
-    #   second optional parameter that always disables caching.
-    # @todo Since the software determines what fetcher must be used to
-    #   fetch it, perhaps this should be a method on {Omnibus::Software}
-    #   instead.
-    def self.without_caching_for(software)
-      if software.source[:url]
-        NetFetcher.new(software)
-      elsif software.source[:git]
-        GitFetcher.new(software)
-      elsif software.source[:path]
-        PathFetcher.new(software)
-      else
-        raise UnsupportedSourceLocation, "Don't know how to fetch software project #{software}"
-      end
-    end
-
-    include Logging
-    include Util
-
-    attr_reader :name
-
-    # @todo What is this?  It doesn't appear to be used anywhere
-    attr_reader :source_timefile
-
+    #
+    # Create a new Fetcher object from the given software.
+    #
+    # @param [Software] software
+    #   the software to create this fetcher
+    #
     def initialize(software)
       @software = software
     end
 
-    # @!group Methods for Subclasses to Implement
+    #
+    # @!group Abstract methods
+    #
+    # The following methods are all abstract and should be overriden in child
+    # classes.
+    # --------------------------------------------------
 
-    # @todo All extenders of this class override this method.  Since
-    #   this class appears to be intended as an abstract one, this
-    #   should raise a NotImplementedError
-    def description
-      # Not as pretty as we'd like, but it's a sane default:
-      inspect
-    end
-
-    # @todo All extenders of this class override this method.  Since
-    #   this class appears to be intended as an abstract one, this
-    #   should raise a NotImplementedError
+    #
+    # @abstract
+    #
     def fetch_required?
-      false
+      raise NotImplementedError
     end
 
-    # @todo Empty method is very suspicious; raise NotImplementedError instead.
+    #
+    # @abstract
+    #
     def clean
+      raise NotImplementedError
     end
 
-    # @todo Empty method is very suspicious; raise NotImplementedError instead.
+    #
+    # @abstract
+    #
     def fetch
+      raise NotImplementedError
     end
 
-    # @todo Empty method is very suspicious; raise NotImplementedError instead.
+    #
+    # @abstract
+    #
     def version_guid
+      raise NotImplementedError
     end
 
-    # Returns the version to be used during build caching.
-    # By default fetchers don't override the versions.
+    #
+    # @abstract
+    #
     def version_for_cache
-      nil
+      raise NotImplementedError
     end
 
+    #
+    # @!endgroup
+    # --------------------------------------------------
+
     private
 
+    #
+    # The "source" for this software, with applied overrides.
+    #
+    # @return [Hash]
+    #
+    def source
+      software.source
+    end
+
+    #
+    # The path where extracted software should live.
+    #
+    # @see Software#project_dir
+    #
+    # @return [String]
+    #
+    def project_dir
+      software.project_dir
+    end
+
+    #
+    # The version for this sfotware, with applied overrides.
+    #
+    # @return [String]
+    #
+    def version
+      software.version
+    end
+
+    #
+    # Override the +log_key+ for this fetcher to include the name of the
+    # software during the fetch.
+    #
+    # @return [String]
+    #
     def log_key
-      @log_key ||= "#{super}: #{@software.name}"
+      @log_key ||= "#{super}: #{software.name}"
     end
 
-    # !@endgroup
+
+    #
+    # Idempotently create the required directories for building/downloading.
+    # Fetchers should call this method before performing any operations that
+    # manipulate the filesystem.
+    #
+    # @return [void]
+    #
+    def create_required_directories
+      [
+        Config.cache_dir,
+        Config.source_dir,
+        software.build_dir,
+        software.project_dir,
+      ].each do |directory|
+        FileUtils.mkdir_p(directory) unless File.directory?(directory)
+      end
+    end
   end
 end