Fix enumeration of local interface IPs (#8)

* Extract only the local IPs and set log flags with shortfile name
* Assign bigquery names based on top level columns
* Log all annotation errors
* Add helper to find local IPs with unit tests

annotator/annotator.go

@@ -20,9 +20,10 @@ var (
 
 // Annotations contains the standard columns we would like to add as annotations for every UUID.
 type Annotations struct {
-	UUID           string
-	Timestamp      time.Time
-	Server, Client api.Annotations
+	UUID      string
+	Timestamp time.Time
+	Server    api.Annotations `bigquery:"server"` // Use Standard Top-Level Column names.
+	Client    api.Annotations `bigquery:"client"` // Use Standard Top-Level Column names.
 }
 
 // Annotator is the interface that all systems that want to add metadata should implement.

handler/handler.go

@@ -69,6 +69,7 @@ func (h *handler) annotateAndSave(j *job) {
 	for _, ann := range h.annotators {
 		err := ann.Annotate(j.id, annotations)
 		if err != nil {
+			log.Println(err)
 			metrics.AnnotationErrors.Inc()
 		}
 	}

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"flag"
+	"log"
 	"net"
 	"net/url"
 	"sync"
@@ -40,6 +41,22 @@ var (
 	mainCtx, mainCancel = context.WithCancel(context.Background())
 )
 
+func init() {
+	log.SetFlags(log.LstdFlags | log.LUTC | log.Lshortfile)
+}
+
+func findLocalIPs(localAddrs []net.Addr) []net.IP {
+	localIPs := []net.IP{}
+	for _, addr := range localAddrs {
+		// By default, addr.String() includes the netblock suffix. By casting to
+		// the underlying net.IPNet we can extract just the IP.
+		if a, ok := addr.(*net.IPNet); ok {
+			localIPs = append(localIPs, a.IP)
+		}
+	}
+	return localIPs
+}
+
 func main() {
 	flag.Parse()
 	rtx.Must(flagx.ArgsFromEnv(flag.CommandLine), "Could not get args from environment variables")
@@ -59,11 +76,8 @@ func main() {
 
 	// Set up IP annotation, first by loading the initial config.
 	localAddrs, err := net.InterfaceAddrs()
-	localIPs := []net.IP{}
-	for _, addr := range localAddrs {
-		localIPs = append(localIPs, net.ParseIP(addr.String()))
-	}
 	rtx.Must(err, "Could not read local addresses")
+	localIPs := findLocalIPs(localAddrs)
 	u, err := url.Parse(*maxmindurl)
 	rtx.Must(err, "Could not parse URL")
 	p, err := zipfile.FromURL(mainCtx, u)

main_test.go

@@ -3,13 +3,14 @@ package main
 import (
 	"context"
 	"io/ioutil"
+	"net"
 	"os"
+	"reflect"
 	"testing"
 	"time"
 
-	"github.com/m-lab/tcp-info/eventsocket"
-
 	"github.com/m-lab/go/rtx"
+	"github.com/m-lab/tcp-info/eventsocket"
 )
 
 func TestMainSmokeTest(t *testing.T) {
@@ -37,3 +38,46 @@ func TestMainSmokeTest(t *testing.T) {
 	// Run main. Full coverage, no crash, and return == success!
 	main()
 }
+
+func Test_findLocalIPs(t *testing.T) {
+	tests := []struct {
+		name  string
+		local []net.Addr
+		want  []net.IP
+	}{
+		{
+			name: "success",
+			local: []net.Addr{
+				&net.IPNet{
+					IP:   net.ParseIP("127.0.0.1"),
+					Mask: net.CIDRMask(24, 32),
+				},
+				&net.IPNet{
+					IP:   net.ParseIP("2001:1900:2100:2d::75"),
+					Mask: net.CIDRMask(64, 128),
+				},
+			},
+			want: []net.IP{
+				net.ParseIP("127.0.0.1"),
+				net.ParseIP("2001:1900:2100:2d::75"),
+			},
+		},
+		{
+			name: "skip-all-return-empty",
+			local: []net.Addr{
+				&net.UnixAddr{
+					Name: "fake-unix",
+					Net:  "unix",
+				},
+			},
+			want: []net.IP{},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := findLocalIPs(tt.local); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("findLocalIPs() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}