(PUP-5120) Add supported_checksum_types setting

Adds a `supported_checksum_types` setting for reporting supported
checksum types to a master for use with file resources in a static
catalog. The `checksum_type` catalog request query parameter will be set
to a dot-separated munging of the list specified in
`supported_checksum_types`.

api/docs/http_catalog.md

@@ -40,7 +40,8 @@ doubly-escaped (it should just be singly-escaped).  To keep backward compatibili
 escaping is still used/supported.
 - `transaction_uuid`: a transaction uuid identifying the entire transaction (shows up in the report as well)
 - `static_catalog`: a boolean requesting a static catalog if available; should always be `true`
-- `checksum_type`: a checksum type supported by the agent, for use in file resources of a static catalog.
+- `checksum_type`: a dot-separated list of checksum types supported by the agent, for use in file resources of a static
+catalog. The order signifies preference, highest first.
 
 An optional parameter can be provided to the POST or GET to notify a node classifier that the client requested a specific
 environment, which might differ from what the client believes is its current environment:
@@ -53,7 +54,7 @@ environment, which might differ from what the client believes is its current env
 
     POST /puppet/v3/catalog/elmo.mydomain.com
 
-    environment=env&configured_environment=canary_env&facts_format=pson&facts=%7B%22name%22%3A%22elmo.mydomain.com%22%2C%22values%22%3A%7B%22architecture%22%3A%22x86_64%22%7D&transaction_uuid=aff261a2-1a34-4647-8c20-ff662ec11c4c&static_catalog=true&checksum_type=md5
+    environment=env&configured_environment=canary_env&facts_format=pson&facts=%7B%22name%22%3A%22elmo.mydomain.com%22%2C%22values%22%3A%7B%22architecture%22%3A%22x86_64%22%7D&transaction_uuid=aff261a2-1a34-4647-8c20-ff662ec11c4c&static_catalog=true&checksum_type=md5.sha256
 
     HTTP 200 OK
     Content-Type: text/pson

lib/puppet/configurer.rb

@@ -51,7 +51,7 @@ def initialize(factory = Puppet::Configurer::DownloaderFactory.new)
     @environment = Puppet[:environment]
     @transaction_uuid = SecureRandom.uuid
     @static_catalog = true
-    @checksum_type = Puppet[:digest_algorithm]
+    @checksum_type = Puppet[:supported_checksum_types]
     @handler = Puppet::Configurer::PluginHandler.new(factory)
   end
 
@@ -115,7 +115,10 @@ def prepare_and_retrieve_catalog(options, query_options)
     options[:report].host = Puppet[:node_name_value]
     query_options[:transaction_uuid] = @transaction_uuid
     query_options[:static_catalog] = @static_catalog
-    query_options[:checksum_type] = @checksum_type
+
+    # Query params don't enforce ordered evaluation, so munge this list into a
+    # dot-separated string.
+    query_options[:checksum_type] = @checksum_type.join('.')
 
     unless catalog = (options.delete(:catalog) || retrieve_catalog(query_options))
       Puppet.err "Could not retrieve catalog; skipping run"

lib/puppet/defaults.rb

@@ -786,6 +786,20 @@ def self.default_diffargs
         :values => ["md5", "sha256"],
         :desc     => 'Which digest algorithm to use for file resources and the filebucket.
                       Valid values are md5, sha256. Default is md5.',
+    },
+    :supported_checksum_types => {
+      :default => ['md5', 'sha256'],
+      :type    => :array,
+      :desc    => 'Checksum types supported by this agent for use in file resources of a static
+        catalog. Valid types are md5, md5lite, sha256, sha256lite, sha1, sha1lite, mtime, ctime.',
+      :hook    => proc do |value|
+        values = munge(value)
+        valid   = ['md5', 'md5lite', 'sha256', 'sha256lite', 'sha1', 'sha1lite', 'mtime', 'ctime']
+        invalid = values.reject {|alg| valid.include?(alg)}
+        if not invalid.empty?
+          raise ArgumentError, "Unrecognized checksum types #{invalid} are not supported. Valid values are #{valid}."
+        end
+      end
     }
   )
 

spec/unit/configurer_spec.rb

@@ -388,21 +388,22 @@
       @agent.run
     end
 
-    it "sets the checksum_type query param to the default digest_algorithm in a catalog request" do
-      Puppet::Resource::Catalog.indirection.expects(:find).with(anything, has_entries(:checksum_type => 'md5'))
+    it "sets the checksum_type query param to the default supported_checksum_types in a catalog request" do
+      Puppet::Resource::Catalog.indirection.expects(:find).with(anything,
+        has_entries(:checksum_type => 'md5.sha256'))
       @agent.run
     end
 
-    it "sets the checksum_type query param to the digest_algorithm setting in a catalog request" do
+    it "sets the checksum_type query param to the supported_checksum_types setting in a catalog request" do
       # Regenerate the agent to pick up the new setting
-      Puppet[:digest_algorithm] = 'sha256'
+      Puppet[:supported_checksum_types] = ['sha256']
       @agent = Puppet::Configurer.new
       @agent.stubs(:init_storage)
       @agent.stubs(:download_plugins)
       @agent.stubs(:send_report)
       @agent.stubs(:save_last_run_summary)
 
-      Puppet::Resource::Catalog.indirection.expects(:find).with(anything, has_entries(:checksum_type => Puppet[:digest_algorithm]))
+      Puppet::Resource::Catalog.indirection.expects(:find).with(anything, has_entries(:checksum_type => 'sha256'))
       @agent.run
     end
 

spec/unit/defaults_spec.rb

@@ -71,4 +71,19 @@
     end
 
   end
+
+  describe 'supported_checksum_types' do
+    it 'should default to md5,sha256' do
+      expect(Puppet.settings[:supported_checksum_types]).to eq(['md5', 'sha256'])
+    end
+
+    it 'should raise an error on an unsupported checksum type' do
+      expect { Puppet.settings[:supported_checksum_types] = ['md5', 'foo'] }.to raise_exception ArgumentError, 'Unrecognized checksum types ["foo"] are not supported. Valid values are ["md5", "md5lite", "sha256", "sha256lite", "sha1", "sha1lite", "mtime", "ctime"].'
+    end
+
+    it 'should not raise an error on setting a valid list of checksum types' do
+      Puppet.settings[:supported_checksum_types] = ['sha256', 'md5lite', 'mtime']
+      expect(Puppet.settings[:supported_checksum_types]).to eq(['sha256', 'md5lite', 'mtime'])
+    end
+  end
 end

spec/unit/type/file/checksum_spec.rb

@@ -76,4 +76,10 @@
       expect(sum).to eq("something")
     end
   end
+
+  it 'should use values allowed by the supported_checksum_types setting' do
+    values = checksum.value_collection.values.reject {|v| v == :none}.map {|v| v.to_s}
+    Puppet.settings[:supported_checksum_types] = values
+    expect(Puppet.settings[:supported_checksum_types]).to eq(values)
+  end
 end