From 009af5be0cb5f3a5e8e03250bdb097c254b28383 Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Tue, 5 Jun 2018 14:20:23 +0000
Subject: [PATCH] Probe: remove backwards-compatibility code when publishing
 reports

Removed to reduce CPU and memory usage in probes.

This code was added in August 2016 so that newer probes could be used
with older apps. Since then we have adopted the stance that new apps
will accept reports from old probes but not vice-versa, on a version
change.
---
 probe/probe.go        |  2 +-
 report/report.go      | 29 -----------------------------
 report/report_test.go | 23 -----------------------
 3 files changed, 1 insertion(+), 53 deletions(-)

diff --git a/probe/probe.go b/probe/probe.go
index 80d1bf458..a9139fc4d 100644
--- a/probe/probe.go
+++ b/probe/probe.go
@@ -200,7 +200,7 @@ ForLoop:
 		}
 	}
 
-	if err := p.publisher.Publish(rpt.BackwardCompatible()); err != nil {
+	if err := p.publisher.Publish(rpt); err != nil {
 		log.Infof("publish: %v", err)
 	}
 }
diff --git a/report/report.go b/report/report.go
index 3542f3b18..7604ac502 100644
--- a/report/report.go
+++ b/report/report.go
@@ -6,7 +6,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/weaveworks/common/mtime"
 	"github.com/weaveworks/scope/common/xfer"
 )
 
@@ -503,34 +502,6 @@ func (r Report) upgradeDNSRecords() Report {
 	return r
 }
 
-// BackwardCompatible returns a new backward-compatible report.
-//
-// This for now creates node's Controls from LatestControls.
-func (r Report) BackwardCompatible() Report {
-	now := mtime.Now()
-	cp := r.Copy()
-	cp.WalkTopologies(func(topology *Topology) {
-		n := Nodes{}
-		for name, node := range topology.Nodes {
-			var controls []string
-			node.LatestControls.ForEach(func(k string, _ time.Time, v NodeControlData) {
-				if !v.Dead {
-					controls = append(controls, k)
-				}
-			})
-			if len(controls) > 0 {
-				node.Controls = NodeControls{
-					Timestamp: now,
-					Controls:  MakeStringSet(controls...),
-				}
-			}
-			n[name] = node
-		}
-		topology.Nodes = n
-	})
-	return cp
-}
-
 // Sampling describes how the packet data sources for this report were
 // sampled. It can be used to calculate effective sample rates. We can't
 // just put the rate here, because that can't be accurately merged. Counts
diff --git a/report/report_test.go b/report/report_test.go
index a87ca74d8..b701a8ef5 100644
--- a/report/report_test.go
+++ b/report/report_test.go
@@ -72,29 +72,6 @@ func TestNode(t *testing.T) {
 	}
 }
 
-func TestReportBackwardCompatibility(t *testing.T) {
-	mtime.NowForce(time.Now())
-	defer mtime.NowReset()
-	rpt := report.MakeReport()
-	controls := map[string]report.NodeControlData{
-		"dead": {
-			Dead: true,
-		},
-		"alive": {
-			Dead: false,
-		},
-	}
-	node := report.MakeNode("foo").WithLatestControls(controls)
-	expectedNode := node.WithControls("alive")
-	rpt.Pod.AddNode(node)
-	expected := report.MakeReport()
-	expected.Pod.AddNode(expectedNode)
-	got := rpt.BackwardCompatible()
-	if !s_reflect.DeepEqual(expected, got) {
-		t.Error(test.Diff(expected, got))
-	}
-}
-
 func TestReportUpgrade(t *testing.T) {
 	mtime.NowForce(time.Now())
 	defer mtime.NowReset()