Introduce support for v3 PuppetDB API for fact retrieval

Author: Kevin Paulisse

lib/octocatalog-diff/facts/puppetdb.rb

@@ -6,6 +6,12 @@ module OctocatalogDiff
   class Facts
     # Deal with facts in PuppetDB
     class PuppetDB
+      # Supporting multiple versions of the PuppetDB API.
+      PUPPETDB_QUERY_FACTS_URL = {
+        '3' => '/v3/nodes/<NODE>/facts',
+        '4' => '/pdb/query/v4/nodes/<NODE>/facts'
+      }.freeze
+
       # Retrieve facts from PuppetDB for a specified node.
       # @param :puppetdb_url [String|Array] => URL to PuppetDB
       # @param :retry [Fixnum] => Retry after timeout (default 0 retries, can be more)
@@ -15,7 +21,8 @@ def self.fact_retriever(options = {}, node)
         # Set up some variables from options
         raise ArgumentError, 'puppetdb_url is required' unless options[:puppetdb_url].is_a?(String)
         raise ArgumentError, 'node must be a non-empty string' unless node.is_a?(String) && node != ''
-        uri = "/pdb/query/v4/nodes/#{node}/facts"
+        puppetdb_api_version = options.fetch(:puppetdb_api_version, 4)
+        uri = PUPPETDB_QUERY_FACTS_URL.fetch(puppetdb_api_version.to_s).gsub('<NODE>', node)
         retries = options.fetch(:retry, 0).to_i
 
         # Construct puppetdb object and options

spec/octocatalog-diff/tests/facts/puppetdb_spec.rb

@@ -30,6 +30,48 @@
     end
   end
 
+  context 'PuppetDB API compatibility layer' do
+    before(:each) do
+      clazz = double('OctocatalogDiff::PuppetDB')
+      allow(clazz).to receive(:get) { |args| [{ 'certname' => 'foo.bar.com', 'name' => 'uri', 'value' => args }] }
+      allow(OctocatalogDiff::PuppetDB).to receive(:new).and_return(clazz)
+    end
+
+    it 'should use the correct URL for API v3' do
+      opts = {
+        puppetdb_api_version: 3,
+        puppetdb_url: 'https://foo.bar.baz:8081'
+      }
+      result = OctocatalogDiff::Facts::PuppetDB.fact_retriever(opts, 'foo.bar.com')
+      expect(result).to eq('name' => 'foo.bar.com', 'values' => { 'uri' => '/v3/nodes/foo.bar.com/facts' })
+    end
+
+    it 'should use the correct URL for API v4' do
+      opts = {
+        puppetdb_api_version: 4,
+        puppetdb_url: 'https://foo.bar.baz:8081'
+      }
+      result = OctocatalogDiff::Facts::PuppetDB.fact_retriever(opts, 'foo.bar.com')
+      expect(result).to eq('name' => 'foo.bar.com', 'values' => { 'uri' => '/pdb/query/v4/nodes/foo.bar.com/facts' })
+    end
+
+    it 'should default to API v4' do
+      opts = {
+        puppetdb_url: 'https://foo.bar.baz:8081'
+      }
+      result = OctocatalogDiff::Facts::PuppetDB.fact_retriever(opts, 'foo.bar.com')
+      expect(result).to eq('name' => 'foo.bar.com', 'values' => { 'uri' => '/pdb/query/v4/nodes/foo.bar.com/facts' })
+    end
+
+    it 'should fail if an unrecognized API version is provided' do
+      opts = {
+        puppetdb_api_version: 9000,
+        puppetdb_url: 'https://foo.bar.baz:8081'
+      }
+      expect { OctocatalogDiff::Facts::PuppetDB.fact_retriever(opts, 'foo.bar.com') }.to raise_error(KeyError)
+    end
+  end
+
   context 'mocking methods for error testing' do
     describe '#fact_retriever' do
       let(:opts) { { puppetdb_url: 'https://mocked-puppetdb.somedomain.xyz:8081', node: 'valid-facts' } }