Add build constraint on Linux-only features

Split Reporter into Linux and non-Linux parts, and stubbed it out for
non-Linux targets.

probe/endpoint/connection_tracker.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package endpoint
 
 import (

probe/endpoint/conntrack.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package endpoint
 
 import (

probe/endpoint/ebpf.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package endpoint
 
 import (

probe/endpoint/ebpf_test.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package endpoint
 
 import (

probe/endpoint/nat.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package endpoint
 
 import (

probe/endpoint/nat_internal_test.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package endpoint
 
 import (

probe/endpoint/reporter.go

@@ -31,13 +31,6 @@ type ReporterConfig struct {
 	DNSSnooper   *DNSSnooper
 }
 
-// Reporter generates Reports containing the Endpoint topology.
-type Reporter struct {
-	conf              ReporterConfig
-	connectionTracker connectionTracker
-	natMapper         natMapper
-}
-
 // SpyDuration is an exported prometheus metric
 var SpyDuration = prometheus.NewSummaryVec(
 	prometheus.SummaryOpts{
@@ -50,40 +43,5 @@ var SpyDuration = prometheus.NewSummaryVec(
 	[]string{},
 )
 
-// NewReporter creates a new Reporter that invokes procspy.Connections to
-// generate a report.Report that contains every discovered (spied) connection
-// on the host machine, at the granularity of host and port. That information
-// is stored in the Endpoint topology. It optionally enriches that topology
-// with process (PID) information.
-func NewReporter(conf ReporterConfig) *Reporter {
-	return &Reporter{
-		conf:              conf,
-		connectionTracker: newConnectionTracker(conf),
-		natMapper:         makeNATMapper(newConntrackFlowWalker(conf.UseConntrack, conf.ProcRoot, conf.BufferSize, true /* natOnly */)),
-	}
-}
-
 // Name of this reporter, for metrics gathering
 func (Reporter) Name() string { return "Endpoint" }
-
-// Stop stop stop
-func (r *Reporter) Stop() {
-	r.connectionTracker.Stop()
-	r.natMapper.stop()
-	if r.conf.Scanner != nil {
-		r.conf.Scanner.Stop()
-	}
-}
-
-// Report implements Reporter.
-func (r *Reporter) Report() (report.Report, error) {
-	defer func(begin time.Time) {
-		SpyDuration.WithLabelValues().Observe(time.Since(begin).Seconds())
-	}(time.Now())
-
-	rpt := report.MakeReport()
-
-	r.connectionTracker.ReportConnections(&rpt)
-	r.natMapper.applyNAT(rpt, r.conf.HostID)
-	return rpt, nil
-}

probe/endpoint/reporter_linux.go

@@ -0,0 +1,51 @@
+// +build linux
+
+package endpoint
+
+import (
+	"time"
+
+	"github.com/weaveworks/scope/report"
+)
+
+// Reporter generates Reports containing the Endpoint topology.
+type Reporter struct {
+	conf              ReporterConfig
+	connectionTracker connectionTracker
+	natMapper         natMapper
+}
+
+// NewReporter creates a new Reporter that invokes procspy.Connections to
+// generate a report.Report that contains every discovered (spied) connection
+// on the host machine, at the granularity of host and port. That information
+// is stored in the Endpoint topology. It optionally enriches that topology
+// with process (PID) information.
+func NewReporter(conf ReporterConfig) *Reporter {
+	return &Reporter{
+		conf:              conf,
+		connectionTracker: newConnectionTracker(conf),
+		natMapper:         makeNATMapper(newConntrackFlowWalker(conf.UseConntrack, conf.ProcRoot, conf.BufferSize, true /* natOnly */)),
+	}
+}
+
+// Stop stop stop
+func (r *Reporter) Stop() {
+	r.connectionTracker.Stop()
+	r.natMapper.stop()
+	if r.conf.Scanner != nil {
+		r.conf.Scanner.Stop()
+	}
+}
+
+// Report implements Reporter.
+func (r *Reporter) Report() (report.Report, error) {
+	defer func(begin time.Time) {
+		SpyDuration.WithLabelValues().Observe(time.Since(begin).Seconds())
+	}(time.Now())
+
+	rpt := report.MakeReport()
+
+	r.connectionTracker.ReportConnections(&rpt)
+	r.natMapper.applyNAT(rpt, r.conf.HostID)
+	return rpt, nil
+}

probe/endpoint/reporter_other.go

@@ -0,0 +1,21 @@
+// +build !linux
+
+package endpoint
+
+import "github.com/weaveworks/scope/report"
+
+// Reporter dummy
+type Reporter struct{}
+
+// NewReporter makes a dummy
+func NewReporter(conf ReporterConfig) *Reporter {
+	return &Reporter{}
+}
+
+// Stop dummy
+func (r *Reporter) Stop() {}
+
+// Report implements Reporter.
+func (r *Reporter) Report() (report.Report, error) {
+	return report.MakeReport(), nil
+}