Fixes #36715 - Add methods to speed up host fact retrieval

app/models/host/base.rb

@@ -47,6 +47,10 @@ class Base < ApplicationRecord
 
     default_scope -> { where(taxonomy_conditions) }
 
+    def self.with_facts
+      includes(:fact_names, :fact_values)
+    end
+
     def self.taxonomy_conditions
       conditions = {}
       if Organization.current.nil? && User.current.present? && !User.current.admin?
@@ -228,6 +232,31 @@ def facts_hash
     end
     alias_method :facts, :facts_hash
 
+    apipie :method, 'List only specific facts about the host.' do
+      desc 'Same as +facts+ macro, but only returns facts with given names.
+            If fact_names and fact_values are already loaded via :includes, this macro will not perform any additional queries.'
+      returns Hash, desc: 'A hash of facts, keys are fact names, values are fact values'
+      example '@host.facts_with_names([\'dmi::memory::size\', \'net::interface::eth0\']) # => { "dmi::memory::size"=>"16 GB", "net::interface::eth0"=>"00:50:56:8a:5c:3c" }', desc: 'Getting specific facts'
+    end
+    def facts_with_names(names_query = [])
+      filtered_names = Set.new(names_query)
+      result = {}
+      names = {} # { fact_name_id => fact_name_name}
+      fact_names.each do |fact_name|
+        next unless filtered_names.empty? || filtered_names.include?(fact_name.name)
+        names[fact_name.id] = fact_name.name
+      end
+      f_values = {} # { fact_name_id => fact_value_value}
+      fact_values.each do |fact_value|
+        next unless names[fact_value.fact_name_id]
+        f_values[fact_value.fact_name_id] = fact_value.value
+      end
+      names.each do |id, name|
+        result[name] = f_values[id]
+      end
+      result
+    end
+
     def ==(comparison_object)
       super ||
         comparison_object.is_a?(Host::Base) &&

app/models/host/managed.rb

@@ -169,7 +169,7 @@ class Jail < ::Safemode::Jail
       :model, :certname, :capabilities, :provider, :subnet, :subnet6, :token, :location, :organization, :provision_method,
       :image_build?, :pxe_build?, :otp, :realm, :nil?, :indent, :primary_interface,
       :provision_interface, :interfaces, :bond_interfaces, :bridge_interfaces, :interfaces_with_identifier,
-      :managed_interfaces, :facts, :facts_hash, :root_pass, :sp_name, :sp_ip, :sp_mac, :sp_subnet, :use_image,
+      :managed_interfaces, :facts, :facts_hash, :facts_with_names, :root_pass, :sp_name, :sp_ip, :sp_mac, :sp_subnet, :use_image,
       :multiboot, :jumpstart_path, :install_path, :miniroot, :medium, :bmc_nic, :templates_used, :owner, :owner_type,
       :ssh_authorized_keys, :pxe_loader, :global_status, :global_status_label, :get_status, :puppetca_token, :last_report, :build?, :smart_proxies, :host_param,
       :virtual, :ram, :sockets, :cores, :params, :pxe_loader_efi?, :comment

app/services/foreman/renderer/scope/macros/loaders.rb

@@ -70,6 +70,11 @@ module Loaders
             end
           end
 
+          def load_hosts_with_facts(fact_names:, search:, permission:, batch: 1_000, includes: nil, limit: nil, select: nil, joins: nil, where: nil, preload: nil)
+            incl = [:fact_values, :fact_names] + (includes || [])
+            load_hosts(search: search, permission: permission, batch: batch, includes: incl, limit: limit, select: select, joins: joins, where: where, preload: preload)
+          end
+
           private
 
           # returns a batched relation, use either

test/models/host_jail_test.rb

@@ -6,7 +6,7 @@ def test_jail_should_include_these_methods
                :organization, :url_for_boot, :hostgroup, :compute_resource, :domain, :ip, :mac, :shortname, :architecture,
                :model, :certname, :capabilities, :provider, :subnet, :token, :location, :organization, :provision_method, :image_build?,
                :pxe_build?, :otp, :realm, :nil?, :indent, :sp_name, :sp_ip, :sp_mac, :sp_subnet, :facts,
-               :facts_hash, :bmc_nic, :templates_used, :owner, :owner_type, :ssh_authorized_keys, :last_report]
+               :facts_with_names, :facts_hash, :bmc_nic, :templates_used, :owner, :owner_type, :ssh_authorized_keys, :last_report]
 
     allowed.each do |m|
       assert Host::Managed::Jail.allowed?(m), "Method #{m} is not available in Host::Managed::Jail while should be allowed."