From cc79b7631ee8efdd4e58a93951f8d63aef672e78 Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Wed, 18 Jul 2018 08:58:07 +0000
Subject: [PATCH] Propagate multiple container values at once

This is more efficient than repeatedly inserting a single value.
---
 render/container.go   |  8 +++-----
 render/render.go      |  7 -------
 report/map_helpers.go | 13 +++++++++++++
 3 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/render/container.go b/render/container.go
index 5228136df..d2f9a6657 100644
--- a/render/container.go
+++ b/render/container.go
@@ -143,11 +143,9 @@ func (r containerWithImageNameRenderer) Render(rpt report.Report) Nodes {
 		imageNameWithoutTag := docker.ImageNameWithoutTag(imageName)
 		imageNodeID := report.MakeContainerImageNodeID(imageNameWithoutTag)
 
-		c = propagateLatest(docker.ImageName, image, c)
-		c = propagateLatest(docker.ImageTag, image, c)
-		c = propagateLatest(docker.ImageSize, image, c)
-		c = propagateLatest(docker.ImageVirtualSize, image, c)
-		c = propagateLatest(docker.ImageLabelPrefix+"works.weave.role", image, c)
+		c.Latest = c.Latest.Propagate(image.Latest, docker.ImageName, docker.ImageTag,
+			docker.ImageSize, docker.ImageVirtualSize, docker.ImageLabelPrefix+"works.weave.role")
+
 		c.Parents = c.Parents.
 			Delete(report.ContainerImage).
 			Add(report.ContainerImage, report.MakeStringSet(imageNodeID))
diff --git a/render/render.go b/render/render.go
index eb3b6c8a2..ee2429d61 100644
--- a/render/render.go
+++ b/render/render.go
@@ -115,13 +115,6 @@ func (m Map) Render(rpt report.Report) Nodes {
 	return output.result(input)
 }
 
-func propagateLatest(key string, from, to report.Node) report.Node {
-	if value, timestamp, ok := from.Latest.LookupEntry(key); ok {
-		to.Latest = to.Latest.Set(key, timestamp, value)
-	}
-	return to
-}
-
 // Condition is a predecate over the entire report that can evaluate to true or false.
 type Condition func(report.Report) bool
 
diff --git a/report/map_helpers.go b/report/map_helpers.go
index 359785465..5339dc6c0 100644
--- a/report/map_helpers.go
+++ b/report/map_helpers.go
@@ -173,3 +173,16 @@ func (m StringLatestMap) addMapEntries(ts time.Time, n map[string]string) String
 	out.fixup()
 	return out
 }
+
+// Propagate a set of latest values from one set to another.
+func (m StringLatestMap) Propagate(from StringLatestMap, keys ...string) StringLatestMap {
+	out := make(StringLatestMap, len(m), len(m)+len(keys))
+	copy(out, m)
+	for _, k := range keys {
+		if v, ts, ok := from.LookupEntry(k); ok {
+			out = append(out, stringLatestEntry{key: k, Value: v, Timestamp: ts})
+		}
+	}
+	out.fixup()
+	return out
+}