Don't download a file if a checksum is specified and we match

Author: ctennis

chef/lib/chef/provider/remote_file.rb

@@ -46,45 +46,48 @@ def do_remote_file(source, path)
         # The current files checksum
         current_checksum = self.checksum(path) if ::File.exists?(path)
 
-        begin
-          # The remote filehandle
-          raw_file = get_from_uri(source)    ||
-                     get_from_server(source, current_checksum) ||
-                     get_from_local_cookbook(source)
-        rescue Net::HTTPRetriableError => e
-          if e.response.kind_of?(Net::HTTPNotModified)
-            Chef::Log.debug("File #{path} is unchanged")
-            return false
-          else
-            raise e
+        unless (@new_resource.checksum && @new_resource.checksum == current_checksum)
+          begin
+            # The remote filehandle
+            raw_file = get_from_uri(source)    ||
+                       get_from_server(source, current_checksum) ||
+                       get_from_local_cookbook(source)
+          rescue Net::HTTPRetriableError => e
+            if e.response.kind_of?(Net::HTTPNotModified)
+              Chef::Log.debug("File #{path} is unchanged")
+              return false
+            else
+              raise e
+            end
           end
-        end
 
-        # If the file exists
-        if ::File.exists?(@new_resource.path)
-          # And it matches the checksum of the raw file
-          @new_resource.checksum(self.checksum(raw_file.path))
-          if @new_resource.checksum != @current_resource.checksum
-            # Updating target file, let's perform a backup!
-            Chef::Log.debug("#{@new_resource} changed from #{@current_resource.checksum} to #{@new_resource.checksum}")
-            Chef::Log.info("Updating #{@new_resource} at #{@new_resource.path}")
-            backup(@new_resource.path)
+          # If the file exists
+          if ::File.exists?(@new_resource.path)
+            # And it matches the checksum of the raw file
+            @new_resource.checksum(self.checksum(raw_file.path))
+            if @new_resource.checksum != @current_resource.checksum
+              # Updating target file, let's perform a backup!
+              Chef::Log.debug("#{@new_resource} changed from #{@current_resource.checksum} to #{@new_resource.checksum}")
+              Chef::Log.info("Updating #{@new_resource} at #{@new_resource.path}")
+              backup(@new_resource.path)
+             end
+          else
+            # We're creating a new file
+            Chef::Log.info("Creating #{@new_resource} at #{@new_resource.path}")
           end
-        else
-          # We're creating a new file
-          Chef::Log.info("Creating #{@new_resource} at #{@new_resource.path}")
-        end
 
-        FileUtils.cp(raw_file.path, @new_resource.path)
-        @new_resource.updated = true
-        
+          FileUtils.cp(raw_file.path, @new_resource.path)
+          @new_resource.updated = true
+
+          # We're done with the file, so make sure to close it if it was open.
+          raw_file.close 
+          true
+        end
+         
         set_owner if @new_resource.owner
         set_group if @new_resource.group
         set_mode  if @new_resource.mode
 
-        # We're done with the file, so make sure to close it if it was open.
-        raw_file.close 
-        true
       end
 
       def get_from_uri(source)

chef/lib/chef/resource/remote_file.rb

@@ -46,6 +46,15 @@ def cookbook(args=nil)
         )
       end
 
+      def checksum(args=nil)
+        set_or_return(
+          :checksum,
+          args,
+          :kind_of => String
+        )
+      end
+
+
     end
   end
 end

chef/spec/unit/provider/remote_file_spec.rb

@@ -65,10 +65,29 @@ def do_remote_file
   end
 
   describe "when given a URI source" do
-    it "should download the file from the remote URL" do
-      @resource.source("http://opscode.com/seattle.txt")
-      @rest.should_receive(:get_rest).with("http://opscode.com/seattle.txt", true).and_return(@tempfile)
-      do_remote_file
+    describe "and given a checksum" do
+      it "should not download the file if the checksum matches" do
+        @resource.checksum("0fd012fdc96e96f8f7cf2046522a54aed0ce470224513e45da6bc1a17a4924aa")
+        @resource.source("http://opscode.com/seattle.txt")
+        @rest.should_not_receive(:get_rest).with("http://opscode.com/seattle.txt", true).and_return(@tempfile)
+        do_remote_file
+      end
+
+      it "should download the file if the checksum matches" do
+        @resource.checksum("this hash doesn't match")
+        @resource.source("http://opscode.com/seattle.txt")
+        @rest.should_receive(:get_rest).with("http://opscode.com/seattle.txt", true).and_return(@tempfile)
+        do_remote_file
+      end
+    end
+
+    describe "and not given a checksum" do
+      it "should download the file from the remote URL" do
+        @resource.checksum(nil)
+        @resource.source("http://opscode.com/seattle.txt")
+        @rest.should_receive(:get_rest).with("http://opscode.com/seattle.txt", true).and_return(@tempfile)
+        do_remote_file
+      end
     end
   end
 

chef/spec/unit/resource/remote_file_spec.rb

@@ -49,5 +49,16 @@
       @resource.cookbook.should == nil
     end
   end
+
+  describe "checksum" do
+    it "should accept a string for the checksum object" do
+      @resource.checksum "asdf"
+      @resource.checksum.should eql("asdf")
+    end
+
+    it "should default to nil" do
+      @resource.checksum.should == nil
+    end
+  end
 
-end
+end