Introduce renderers; allow them to recurse.

render/render.go

@@ -0,0 +1,51 @@
+package render
+
+import (
+	"github.com/weaveworks/scope/report"
+)
+
+// Renderer is something that can render a report to a set of RenderableNodes
+type Renderer interface {
+	Render(report.Report) report.RenderableNodes
+	AggregateMetadata(rpt report.Report, localID, remoteID string) report.AggregateMetadata
+}
+
+// Reduce renderer is a Renderer which merges together the output of several
+// other renderers
+type Reduce []Renderer
+
+// Render produces a set of RenderableNodes given a Report
+func (r Reduce) Render(rpt report.Report) report.RenderableNodes {
+	result := report.RenderableNodes{}
+	for _, renderer := range r {
+		result.Merge(renderer.Render(rpt))
+	}
+	return result
+}
+
+// AggregateMetadata produces an AggregateMetadata for a given edge
+func (r Reduce) AggregateMetadata(rpt report.Report, localID, remoteID string) report.AggregateMetadata {
+	metadata := report.AggregateMetadata{}
+	for _, renderer := range r {
+		metadata.Merge(renderer.AggregateMetadata(rpt, localID, remoteID))
+	}
+	return metadata
+}
+
+// Map is a Renderer which produces a set of RendererNodes by using a
+// Mapper functions and topology selector.
+type Map struct {
+	Selector report.TopologySelector
+	Mapper   report.MapFunc
+	Pseudo   report.PseudoFunc
+}
+
+// Render produces a set of RenderableNodes given a Report
+func (m Map) Render(rpt report.Report) report.RenderableNodes {
+	return m.Selector(rpt).RenderBy(m.Mapper, m.Pseudo)
+}
+
+// AggregateMetadata produces an AggregateMetadata for a given edge
+func (m Map) AggregateMetadata(rpt report.Report, localID, remoteID string) report.AggregateMetadata {
+	return m.Selector(rpt).EdgeMetadata(m.Mapper, localID, remoteID).Transform()
+}

render/render_test.go

@@ -0,0 +1,49 @@
+package render_test
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/weaveworks/scope/render"
+	"github.com/weaveworks/scope/report"
+)
+
+type mockRenderer struct {
+	report.RenderableNodes
+	aggregateMetadata report.AggregateMetadata
+}
+
+func (m mockRenderer) Render(rpt report.Report) report.RenderableNodes {
+	return m.RenderableNodes
+}
+func (m mockRenderer) AggregateMetadata(rpt report.Report, localID, remoteID string) report.AggregateMetadata {
+	return m.aggregateMetadata
+}
+
+func TestReduceRender(t *testing.T) {
+	renderer := render.Reduce([]render.Renderer{
+		mockRenderer{RenderableNodes: report.RenderableNodes{"foo": {ID: "foo"}}},
+		mockRenderer{RenderableNodes: report.RenderableNodes{"bar": {ID: "bar"}}},
+	})
+
+	want := report.RenderableNodes{"foo": {ID: "foo"}, "bar": {ID: "bar"}}
+	have := renderer.Render(report.MakeReport())
+
+	if !reflect.DeepEqual(want, have) {
+		t.Errorf("want %+v, have %+v", want, have)
+	}
+}
+
+func TestReduceEdge(t *testing.T) {
+	renderer := render.Reduce([]render.Renderer{
+		mockRenderer{aggregateMetadata: report.AggregateMetadata{"foo": 1}},
+		mockRenderer{aggregateMetadata: report.AggregateMetadata{"bar": 2}},
+	})
+
+	want := report.AggregateMetadata{"foo": 1, "bar": 2}
+	have := renderer.AggregateMetadata(report.MakeReport(), "", "")
+
+	if !reflect.DeepEqual(want, have) {
+		t.Errorf("want %+v, have %+v", want, have)
+	}
+}