(BKR-1484) Packaging platform overrides for puppet5 install utils

Allows the environment variable BEAKER_PACKAGING_PLATFORMS to override
the default packaging platforms specified for hosts by
beaker-hostgenerator in `host_urls`. BEAKER_PACKAGING_PLATFORMS should
be a comma-separated list with entries of the format
`<platform-name>=<packaging-platform-name>`.

Author: caseywilliams

lib/beaker-puppet/install_utils/puppet5.rb

@@ -27,7 +27,29 @@ def fetch_build_details(sha_yaml_url)
         return sha_yaml_folder_url, file_hash[:platform_data]
       end
 
-      # gets the artifact & repo_config URLs for this host in the build
+      # Get the host's packaging platform, based on beaker-hostgenerator's
+      # osinfo hash and the environment. Set ENV['BEAKER_PACKAGING_PLATFORMS']
+      # to override the default packaging platform specified by
+      # beaker-hostgenerator. This should be a comma-separated string with
+      # entries of the format `<host-platform>=<override-platform>`
+      #
+      # @param [Host] host Host whose packaging platform to determine
+      # @return [String] The packaging platform
+      def host_packaging_platform(host)
+        packaging_platform = host[:packaging_platform]
+        if ENV['BEAKER_PACKAGING_PLATFORMS']
+          overrides = Hash[ENV['BEAKER_PACKAGING_PLATFORMS'].split(',').map { |e| e.split('=') }]
+          logger.debug("Found packaging platform overrides: #{overrides}")
+          if overrides[host[:platform]]
+            platform = overrides[host[:platform]]
+            logger.debug("Default beaker packaging platform '#{host[:packaging_platform]}' for '#{host[:platform]}' overridden as '#{platform}'")
+            packaging_platform = platform
+          end
+        end
+        packaging_platform
+      end
+
+      # Gets the artifact & repo_config URLs for this host in the build.
       #
       # @param [Host] host Host to get artifact URL for
       # @param [Hash] build_details Details of the build in a hash
@@ -36,7 +58,7 @@ def fetch_build_details(sha_yaml_url)
       # @return [String, String] URL to the build artifact, URL to the repo_config
       #   (nil if there is no repo_config for this platform for this build)
       def host_urls(host, build_details, build_url)
-        packaging_platform = host[:packaging_platform]
+        packaging_platform = host_packaging_platform(host)
         if packaging_platform.nil?
           message = <<-EOF
             :packaging_platform not provided for host '#{host}', platform '#{host[:platform]}'

spec/beaker-puppet/install_utils/puppet5_spec.rb

@@ -78,6 +78,10 @@ def logger
       details
     }
 
+    before :each do
+      allow( subject ).to receive( :host_packaging_platform ) { packaging_platform }
+    end
+
     it 'fails if there\'s no artifact value for the given platform' do
       allow( artifact_path ).to receive( :nil? ) { true }
       expect {
@@ -135,6 +139,41 @@ def logger
 
   end
 
+  describe "#host_packaging_platform" do
+    let( :default_platform ) { 'default-platform' }
+    let( :overridden_platform ) { 'overridden-platform' }
+    let( :overrides ) { 'default-platform=overridden-platform' || @overrides }
+    let( :host ) {
+      host = hosts[0]
+      allow( host ).to receive( :[] ).with( :packaging_platform ) { default_platform }
+      allow( host ).to receive( :[] ).with( :platform ) { default_platform }
+      host
+    }
+
+    before :each do
+      @original_platforms = ENV['BEAKER_PACKAGING_PLATFORMS']
+    end
+
+    after :each do
+      ENV['BEAKER_PACKAGING_PLATFORMS'] = @original_platforms
+    end
+
+    it "applies an override to a platform" do
+      ENV['BEAKER_PACKAGING_PLATFORMS'] = overrides
+      expect(subject.host_packaging_platform(host)).to eq(overridden_platform)
+    end
+
+    it "applies a list of overrides to a platform" do
+      ENV['BEAKER_PACKAGING_PLATFORMS'] = "aix-7.1-power=aix-6.1-power,#{overrides}"
+      expect(subject.host_packaging_platform(host)).to eq(overridden_platform)
+    end
+
+    it "doesn't apply overrides if the current host's platform isn't overridden" do
+      ENV['BEAKER_PACKAGING_PLATFORMS'] = "aix-7.1-power=aix-6.1-power"
+      expect(subject.host_packaging_platform(host)).to eq(default_platform)
+    end
+  end
+
   describe '#install_artifact_on' do
 
     let( :artifact_url ) { 'url://in/the/jungle/lies/the/prize.pnc' }