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()
+}