feat: add before_sideload hook (#371)

* Add before_sideload hook to allow restoration of global state in sideload threads, .e.g. setting current tenant for sideloads

Co-authored-by: Jeff Keen <[email protected]>

lib/graphiti/configuration.rb

@@ -15,6 +15,7 @@ class Configuration
     attr_accessor :pagination_links
     attr_accessor :typecast_reads
     attr_accessor :raise_on_missing_sidepost
+    attr_accessor :before_sideload
 
     attr_reader :debug, :debug_models
 

lib/graphiti/scope.rb

@@ -43,6 +43,7 @@ def resolve_sideloads(results)
         parent_resource = @resource
         graphiti_context = Graphiti.context
         resolve_sideload = -> {
+          Graphiti.config.before_sideload&.call(graphiti_context)
           Graphiti.context = graphiti_context
           sideload.resolve(results, q, parent_resource)
           @resource.adapter.close if concurrent

spec/scope_spec.rb

@@ -94,14 +94,24 @@
       end
 
       context "with concurrency" do
+        let(:before_sideload) { double("BeforeSideload", call: nil) }
+
         before { allow(Graphiti.config).to receive(:concurrency).and_return(true) }
+        before { allow(Graphiti.config).to receive(:before_sideload).and_return(before_sideload) }
 
         it "closes db connections" do
           allow(sideload).to receive(:resolve).and_return(sideload)
 
           expect(resource.adapter).to receive(:close)
           instance.resolve_sideloads(results)
         end
+
+        it "calls configiration.before_sideload with context" do
+          Graphiti.context[:tenant_id] = 1
+          allow(sideload).to receive(:resolve).and_return(sideload)
+          expect(before_sideload).to receive(:call).with(hash_including(tenant_id: 1))
+          instance.resolve_sideloads(results)
+        end
       end
 
       context "without concurrency" do