[puppetlabs#1058] Serially deploy modules that share a cachedir

When we raised the default threadpool for deploying modules above 1, we
began to see issues when caching a remote locally if that remote/cache
was shared by multiple modules within the Puppetfile.

To resolve this, when we create the module we group it with any other
module that may share its cachedir. We then pull modules by cachedir off
of the queue and serially process those.

lib/r10k/git/cache.rb

@@ -99,10 +99,8 @@ def reset!
 
   alias cached? exist?
 
-  private
-
   # Reformat the remote name into something that can be used as a directory
   def sanitized_dirname
-    @remote.gsub(/[^@\w\.-]/, '-')
+    @sanitized_dirname ||= @remote.gsub(/[^@\w\.-]/, '-')
   end
 end

lib/r10k/puppetfile.rb

@@ -42,6 +42,11 @@ class Puppetfile
   #   @return [Boolean] Overwrite any locally made changes
   attr_accessor :force
 
+  # @!attribute [r] modules_by_vcs_cachedir
+  #   @api private Only exposed for testing purposes
+  #   @return [Hash{:none, String => Array<R10K::Module>}]
+  attr_reader :modules_by_vcs_cachedir
+
   # @param [String] basedir
   # @param [String] moduledir The directory to install the modules, default to #{basedir}/modules
   # @param [String] puppetfile_path The path to the Puppetfile, default to #{basedir}/Puppetfile
@@ -58,6 +63,7 @@ def initialize(basedir, moduledir = nil, puppetfile_path = nil, puppetfile_name
 
     @modules = []
     @managed_content = {}
+    @modules_by_vcs_cachedir = Hash.new { [] }
     @forge   = 'forgeapi.puppetlabs.com'
 
     @loaded = false
@@ -137,6 +143,7 @@ def add_module(name, args)
     mod.origin = 'Puppetfile'
 
     @managed_content[install_path] << mod.name
+    @modules_by_vcs_cachedir[module_vcs_cachedir(mod)] << mod
     @modules << mod
   end
 
@@ -180,6 +187,19 @@ def accept(visitor)
 
   private
 
+  def module_vcs_cachedir(mod)
+    if mod.respond_to? :repo
+      repo = mod.repo
+      if repo.respond_to? :cache
+        cache = repo.cache
+        if cache.respond_to? :sanitized_dirname
+          return cache.sanitized_dirname
+        end
+      end
+    end
+    :none
+  end
+
   def serial_accept(visitor)
     visitor.visit(:puppetfile, self) do
       modules.each do |mod|
@@ -212,15 +232,21 @@ def concurrent_accept(visitor, pool_size)
   def modules_queue(visitor)
     Queue.new.tap do |queue|
       visitor.visit(:puppetfile, self) do
-        modules.each { |mod| queue << mod }
+        modules_by_cachedir = modules_by_vcs_cachedir.clone
+        modules_without_vcs_cachedir = modules_by_cachedir.delete(:none) || []
+
+        modules_without_vcs_cachedir.each {|mod| queue << Array(mod) }
+        modules_by_cachedir.values.each {|mods| queue << mods }
       end
     end
   end
 
   def visitor_thread(visitor, mods_queue)
     Thread.new do
       begin
-        while mod = mods_queue.pop(true) do mod.accept(visitor) end
+        while mods = mods_queue.pop(true) do
+          mods.each {|mod| mod.accept(visitor) }
+        end
       rescue ThreadError => e
         logger.debug _("Module thread %{id} exiting: %{message}") % {message: e.message, id: Thread.current.object_id}
         Thread.exit

spec/unit/action/deploy/module_spec.rb

@@ -70,8 +70,8 @@
 
       before do
         allow(subject).to receive(:visit_environment).and_wrap_original do |original, environment, &block|
-          expect(environment.puppetfile).to receive(:modules).and_return(
-            [R10K::Module::Local.new(environment.name, '/fakedir', [], environment)]
+          expect(environment.puppetfile).to receive(:modules_by_vcs_cachedir).and_return(
+            {none: [R10K::Module::Local.new(environment.name, '/fakedir', [], environment)]}
           )
           original.call(environment, &block)
         end

spec/unit/action/puppetfile/install_spec.rb

@@ -27,6 +27,7 @@ def installer(opts = {}, argv = [], settings = {})
     before do
       allow(puppetfile).to receive(:purge!)
       allow(puppetfile).to receive(:modules).and_return(modules)
+      allow(puppetfile).to receive(:modules_by_vcs_cachedir).and_return({none: modules})
     end
 
     it "syncs each module in the Puppetfile" do

spec/unit/puppetfile_spec.rb

@@ -268,7 +268,7 @@ def expect_wrapped_error(orig, pf_path, wrapped_error)
       mod2 = spy('module')
       expect(mod2).to receive(:accept).with(visitor)
 
-      expect(subject).to receive(:modules).and_return([mod1, mod2])
+      expect(subject).to receive(:modules_by_vcs_cachedir).and_return({none: [mod1, mod2]})
       subject.accept(visitor)
     end
 
@@ -289,7 +289,7 @@ def expect_wrapped_error(orig, pf_path, wrapped_error)
       mod2 = spy('module')
       expect(mod2).to receive(:accept).with(visitor)
 
-      expect(subject).to receive(:modules).and_return([mod1, mod2])
+      expect(subject).to receive(:modules_by_vcs_cachedir).and_return({none: [mod1, mod2]})
 
       expect(Thread).to receive(:new).exactly(pool_size).and_call_original
       expect(Queue).to receive(:new).and_call_original