Implement strip_component source feature

CHANGELOG.mkd

@@ -4,6 +4,8 @@ CHANGELOG
 Unreleased
 ----------
 
+- Add 'strip\_component' environment source configuration setting, to allow deploying Git branches named like "env/production" as Puppet environments named like "production". [#1128](https://github.com/puppetlabs/r10k/pull/1128)
+
 3.8.0
 -----
 

doc/dynamic-environments/configuration.mkd

@@ -394,6 +394,23 @@ sources:
 * if `false` (default) environment folder will not be prefixed
 * if `String` environment folder will be prefixed with the `prefix` value.
 
+### strip\_component
+
+The 'strip\_component' setting allows parts of environment names from a source to have a transformation applied, removing a part of the name before turning them into Puppet environments. This is primarily useful for VCS sources (e.g.  Git), because it allows branch names to use prefixes or organizing name components such as "env/production", "env/development", but deploy Puppet environments from these branches named without the leading "env/" component. E.g. "production", "development".
+
+```yaml
+---
+sources:
+  mysource:
+    basedir: '/etc/puppet/environments'
+    strip_component: 'env/'
+```
+
+#### strip\_component behaviour
+
+* if `string` environment names will have this prefix removed, if the prefix is present. Note that when string values are used, names can only have prefix components removed.
+* if `/regex/` the regex will be matched against environment names and if a match is found, the matching name component will be removed.
+
 ### ignore_branch_prefixes
 
 The 'ignore_branch_prefixes' setting causes environments to be ignored which match in part or whole

lib/r10k/environment/name.rb

@@ -12,13 +12,13 @@ class Name
       INVALID_CHARACTERS = %r[\W]
 
       def initialize(name, opts)
-        @name   = name
-        @opts   = opts
-
         @source  = opts[:source]
         @prefix  = opts[:prefix]
         @invalid = opts[:invalid]
 
+        @name = derive_name(name, opts[:strip_component])
+        @opts = opts
+
         case @invalid
         when 'correct_and_warn'
           @validate = true
@@ -71,8 +71,24 @@ def dirname
 
       private
 
-      def derive_prefix(source,prefix)
+      def derive_name(name, strip_component)
+        if strip_component == nil
+          name
+        elsif %r{^/.*/$}.match(strip_component)
+          regex = Regexp.new(strip_component[1..-2])
+          name.gsub(regex, '')
+        elsif name.start_with?(strip_component)
+          name[strip_component.size..-1]
+        else
+          name
+        end
+      rescue TypeError, NoMethodError
+        raise _('Improper configuration value given for strip_component setting in %{src} source. ' \
+                'Value must be a string, a /regex/, or omitted. Got "%{val}" (%{type})' \
+                % {src: @source, val: strip_component, type: strip_component.class})
+      end
 
+      def derive_prefix(source,prefix)
         if prefix == true
           "#{source}_"
         elsif prefix.is_a? String

lib/r10k/source/base.rb

@@ -31,10 +31,15 @@ class R10K::Source::Base
   # @option options [Boolean, String] :prefix If a String this becomes the prefix.
   #   If true, will use the source name as the prefix. All sources should respect this option.
   #   Defaults to false for no environment prefix.
+  # @option options [String] :strip_component If a string, this value will be
+  #   removed from the beginning of each generated environment's name, if
+  #   present. If the string is contained within two "/" characters, it will
+  #   be treated as a regular expression.
   def initialize(name, basedir, options = {})
     @name    = name
     @basedir = Pathname.new(basedir).cleanpath.to_s
     @prefix  = options.delete(:prefix)
+    @strip_component = options.delete(:strip_component)
     @puppetfile_name = options.delete(:puppetfile_name)
     @options = options
   end

lib/r10k/source/git.rb

@@ -145,7 +145,10 @@ def filter_branches_by_command(branches, command)
   private
 
   def branch_names
-    opts = {:prefix => @prefix, :invalid => @invalid_branches, :source => @name}
+    opts = {prefix: @prefix,
+            invalid: @invalid_branches,
+            source: @name,
+            strip_component: @strip_component}
     branches = @cache.branches
     if @ignore_branch_prefixes && !@ignore_branch_prefixes.empty?
       branches = filter_branches_by_regexp(branches, @ignore_branch_prefixes)

lib/r10k/source/hash.rb

@@ -152,8 +152,10 @@ def set_environments_hash(hash)
       R10K::Util::SymbolizeKeys.symbolize_keys!(opts)
       memo.merge({ 
         name => opts.merge({
-          :basedir => @basedir,
-          :dirname => R10K::Environment::Name.new(name, {prefix: @prefix, source: @name}).dirname
+          basedir: @basedir,
+          dirname: R10K::Environment::Name.new(name, {prefix: @prefix,
+                                                      source: @name,
+                                                      strip_component: @strip_component}).dirname
         })
       })
     end

lib/r10k/source/svn.rb

@@ -121,7 +121,11 @@ def filter_branches(branches, ignore_prefixes)
 
   def names_and_paths
     branches = []
-    opts = {:prefix => @prefix, :correct => false, :validate => false, :source => @name}
+    opts = {prefix: @prefix,
+            correct: false,
+            validate: false,
+            source: @name,
+            strip_component: @strip_component}
     branches << [R10K::Environment::Name.new('production', opts), "#{@remote}/trunk"]
     additional_branch_names = @svn_remote.branches
     if @ignore_branch_prefixes && !@ignore_branch_prefixes.empty?

spec/unit/environment/name_spec.rb

@@ -2,6 +2,34 @@
 require 'r10k/environment/name'
 
 describe R10K::Environment::Name do
+  describe "strip_component" do
+    it "does not modify the given name when no strip_component is given" do
+      bn = described_class.new('myenv', source: 'source', prefix: false)
+      expect(bn.dirname).to eq 'myenv'
+    end
+
+    it "removes the first occurance of a regex match when a regex is given" do
+      bn = described_class.new('myenv', source: 'source', prefix: false, strip_component: '/env/')
+      expect(bn.dirname).to eq 'my'
+    end
+
+    it "does not modify the given name when there is no regex match" do
+      bn = described_class.new('myenv', source: 'source', prefix: false, strip_component: '/bar/')
+      expect(bn.dirname).to eq 'myenv'
+    end
+
+    it "removes the given name's prefix when it matches strip_component" do
+      bn = described_class.new('env/prod', source: 'source', prefix: false, strip_component: 'env/')
+      expect(bn.dirname).to eq 'prod'
+    end
+
+    it "raises an error when given an integer" do
+      expect {
+        described_class.new('env/prod', source: 'source', prefix: false, strip_component: 4)
+      }.to raise_error(%r{Improper.*"4"})
+    end
+  end
+
   describe "prefixing" do
     it "uses the branch name as the dirname when prefixing is off" do
       bn = described_class.new('mybranch', :source => 'source', :prefix => false)