[#4055] Add CouchDB terminus for facts

Implements an abstract CouchDB terminus and a concrete CouchDB terminus
used to store node facts. Node facts are stored in a "node" document as
the "facts" attribute. This node document may also be used by other
couchdb termini that store node-related information. It is recommended
to use a separate document (or documents) to store large data structures
like catalogs, linking them to their related node document using
embedded ids.

This implementation depends on the "couchrest" gem.

* Add Puppet.features.couchdb?
* Add Puppet[:couchdb_url] setting
* Add Puppet::Node::Facts#== for testing
* Add PuppetSpec::FIXTURE_DIR for easy access to fixture files
* Add CouchDB Terminus
* Add Facts::CouchDB terminus
  * Stores facts inside a "node" document
  * Use key (hostname) as _id for node document
  * #find returns nil if document cannot be found
  * #save finds and updates existing document OR creates new doc  [1]
  * Store facts in "facts" attribute of node document

5 files changed, 111 insertions, 0 deletions

diff --git a/lib/puppet/defaults.rb b/lib/puppet/defaults.rb
index 78f4cd52e..9de73f526 100644
--- a/lib/puppet/defaults.rb
+++ b/lib/puppet/defaults.rb
@@ -680,6 +680,10 @@ module Puppet
             and other environments normally use ``debug``."]
     )
 
+    setdefaults(:couchdb,
+        :couchdb_url => ["http://127.0.0.1:5984/puppet", "The url where the puppet couchdb database will be created"]
+    )
+
     setdefaults(:transaction,
         :tags => ["", "Tags to use to find resources.  If this is set, then
             only resources tagged with the specified tags will be applied.
diff --git a/lib/puppet/feature/base.rb b/lib/puppet/feature/base.rb
index 8a21fd30f..0ca408ce4 100644
--- a/lib/puppet/feature/base.rb
+++ b/lib/puppet/feature/base.rb
@@ -45,3 +45,6 @@ end
 Puppet.features.add(:win32, :libs => ["sys/admin", "win32/process", "win32/dir"])
 
 raise Puppet::Error "Cannot determine basic system flavour" unless Puppet.features.posix? or Puppet.features.win32?
+
+# We have CouchDB
+Puppet.features.add(:couchdb, :libs => ["couchrest"])
diff --git a/lib/puppet/indirector/couch.rb b/lib/puppet/indirector/couch.rb
new file mode 100644
index 000000000..b328f5cb7
--- /dev/null
+++ b/lib/puppet/indirector/couch.rb
@@ -0,0 +1,68 @@
+require 'couchrest'
+class Puppet::Indirector::Couch < Puppet::Indirector::Terminus
+
+    # The CouchRest database instance. One database instance per Puppet runtime
+    # should be sufficient.
+    #
+    def self.db
+        @db ||= CouchRest.database! Puppet[:couchdb_url]
+    end
+
+    def db; self.class.db end
+
+    def find(request)
+        attributes_of db.get(id_for(request))
+    rescue RestClient::ResourceNotFound
+        Puppet.debug "No couchdb document with id: #{id_for(request)}"
+        return nil
+    end
+
+    # Create or update the couchdb document with the request's data hash.
+    #
+    # RKH:TODO: Do not depend on error handling, check if the document exists
+    # first. (Does couchrest support this?)
+    #
+    def save(request)
+        raise ArgumentError, "PUT does not accept options" unless request.options.empty?
+
+        # Try to find an existing document.
+        doc = db.get(id_for(request))
+        doc.merge(hash_from(request))
+        doc.save
+    rescue RestClient::ResourceNotFound
+        # Document does not yet exist, create it
+        db.save_doc hash_from(request)
+    end
+
+    private
+
+    # The attributes hash that is serialized to CouchDB as JSON. It includes
+    # metadata that is used to help aggregate data in couchdb. Add
+    # model-specific attributes in subclasses.
+    #
+    def hash_from(request)
+        {
+            "_id"         => id_for(request),
+            "puppet_type" => document_type_for(request)
+        }
+    end
+
+    # The couchdb response stripped of metadata, used to instantiate the model
+    # instance that is returned by save.
+    #
+    def attributes_of(response)
+        response.reject{|k,v| k =~ /^(_rev|puppet_)/ }
+    end
+
+    def document_type_for(request)
+        request.indirection_name
+    end
+
+    # The id used to store the object in couchdb. Implemented in subclasses.
+    #
+    def id_for(request)
+        raise NotImplementedError
+    end
+
+end
+
diff --git a/lib/puppet/indirector/facts/couch.rb b/lib/puppet/indirector/facts/couch.rb
new file mode 100644
index 000000000..522fe3350
--- /dev/null
+++ b/lib/puppet/indirector/facts/couch.rb
@@ -0,0 +1,31 @@
+require 'puppet/node/facts'
+require 'puppet/indirector/couch'
+class Puppet::Node::Facts::Couch < Puppet::Indirector::Couch
+
+    # Return the facts object or nil if there is no document
+    def find(request)
+        doc = super
+        doc ? model.new(doc['_id'], doc['facts']) : nil
+    end
+
+    private
+
+    # Facts values are stored to the document's 'facts' attribute. Hostname is
+    # stored to 'name'
+    #
+    def hash_from(request)
+        super.merge('facts' => request.instance.values)
+    end
+
+    # Facts are stored to the 'node' document.
+    def document_type_for(request)
+        'node'
+    end
+
+    # The id used to store the object in couchdb.
+    def id_for(request)
+        request.key.to_s
+    end
+
+end
+
diff --git a/lib/puppet/node/facts.rb b/lib/puppet/node/facts.rb
index 2b086afea..0b9fc5879 100755
--- a/lib/puppet/node/facts.rb
+++ b/lib/puppet/node/facts.rb
@@ -49,6 +49,11 @@ class Puppet::Node::Facts
         end
     end
 
+    def ==(other)
+        return false unless self.name == other.name
+        strip_internal == other.send(:strip_internal)
+    end
+
     private
 
     # Add internal data to the facts for storage.