add a #nodes api to the job adapters

lib/ood_core/job/adapter.rb

@@ -213,6 +213,14 @@ def accounts
       def queues
         []
       end
+
+      # Return the list of nodes for this scheduler.
+      #
+      # Subclasses that do not implement this will return empty arrays.
+      # @return [Array<NodeInfo>]
+      def nodes
+        []
+      end
     end
   end
 end

lib/ood_core/job/adapters/slurm.rb

@@ -332,6 +332,30 @@ def queues
             end
           end
 
+          def all_sinfo_node_fields
+            {
+              procs: '%c',
+              name: '%n',
+              features: '%f'
+            }
+          end
+
+          def nodes
+            args = all_sinfo_node_fields.values.join(UNIT_SEPARATOR)
+            output = call('sinfo', '-ho', "#{RECORD_SEPARATOR}#{args}")
+
+            output.each_line(RECORD_SEPARATOR).map do |line|
+              values = line.chomp(RECORD_SEPARATOR).strip.split(UNIT_SEPARATOR)
+
+              next if values.empty?
+
+              data = Hash[all_sinfo_node_fields.keys.zip(values)]
+              data[:name] = data[:name].to_s.split(',').first
+              data[:features] = data[:features].to_s.split(',')
+              NodeInfo.new(**data)
+            end.compact
+          end
+
           private
             def str_to_acct_info(line)
               hsh = line.split(' ').map do |token|
@@ -669,6 +693,10 @@ def queues
           @slurm.queues
         end
 
+        def nodes
+          @slurm.nodes
+        end
+
         private
           # Convert duration to seconds
           def duration_in_seconds(time)

lib/ood_core/job/node_info.rb

@@ -10,17 +10,26 @@ class NodeInfo
       # @return [Integer, nil] number of procs
       attr_reader :procs
 
+      # The features associated with this node.
+      # @return [Array<String>, []]
+      attr_reader :features
+
       # @param name [#to_s] node name
       # @param procs [#to_i, nil] number of procs
-      def initialize(name:, procs: nil, **_)
+      # @param features [#to_a, []] list of features
+      def initialize(name:, procs: nil, features: [], **_)
         @name  = name.to_s
         @procs = procs && procs.to_i
+        @features = features.to_a
       end
 
       # Convert object to hash
       # @return [Hash] object as hash
       def to_h
-        { name: name, procs: procs }
+        instance_variables.map do |var|
+          name = var.to_s.gsub('@', '').to_sym
+          [name, send(name)]
+        end.to_h
       end
 
       # The comparison operator