Dedupe probe POSTs

app/main.go

@@ -16,8 +16,13 @@ import (
 	"github.com/weaveworks/scope/xfer"
 )
 
-// Set during buildtime.
-var version = "dev"
+var (
+	// Set at buildtime.
+	version = "dev"
+
+	// Set at runtime.
+	uniqueID = "0"
+)
 
 func main() {
 	var (
@@ -33,8 +38,8 @@ func main() {
 	}
 
 	rand.Seed(time.Now().UnixNano())
-	id := strconv.FormatInt(rand.Int63(), 16)
-	log.Printf("app starting, version %s, ID %s", version, id)
+	uniqueID = strconv.FormatInt(rand.Int63(), 16)
+	log.Printf("app starting, version %s, ID %s", version, uniqueID)
 
 	c := xfer.NewCollector(*window)
 	http.Handle("/", Router(c))

app/router.go

@@ -121,11 +121,12 @@ func captureTopology(rep xfer.Reporter, f func(xfer.Reporter, topologyView, http
 
 // APIDetails are some generic details that can be fetched from /api
 type APIDetails struct {
+	ID      string `json:"id"`
 	Version string `json:"version"`
 }
 
 func apiHandler(w http.ResponseWriter, r *http.Request) {
-	respondWith(w, http.StatusOK, APIDetails{Version: version})
+	respondWith(w, http.StatusOK, APIDetails{ID: uniqueID, Version: version})
 }
 
 // Topology option labels should tell the current state. The first item must

common/sanitize/sanitize.go

@@ -0,0 +1,39 @@
+package sanitize
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"net/url"
+	"strings"
+)
+
+// URL returns a function that sanitizes a URL string. It lets underspecified
+// strings to be converted to usable URLs via some default arguments.
+func URL(scheme string, port int, path string) func(string) string {
+	if scheme == "" {
+		scheme = "http://"
+	}
+	return func(s string) string {
+		if s == "" {
+			return s // can't do much here
+		}
+		if !strings.HasPrefix(s, "http") {
+			s = scheme + s
+		}
+		u, err := url.Parse(s)
+		if err != nil {
+			log.Printf("%q: %v", s, err)
+			return s // oh well
+		}
+		if port > 0 {
+			if _, _, err = net.SplitHostPort(u.Host); err != nil {
+				u.Host += fmt.Sprintf(":%d", port)
+			}
+		}
+		if path != "" && u.Path != path {
+			u.Path = path
+		}
+		return u.String()
+	}
+}

common/sanitize/sanitize_test.go

@@ -0,0 +1,34 @@
+package sanitize_test
+
+import (
+	"testing"
+
+	"github.com/weaveworks/scope/common/sanitize"
+)
+
+func TestSanitizeURL(t *testing.T) {
+	for _, input := range []struct {
+		scheme string
+		port   int
+		path   string
+		input  string
+		want   string
+	}{
+		{"", 0, "", "", ""},
+		{"", 0, "", "foo", "http://foo"},
+		{"", 80, "", "foo", "http://foo:80"},
+		{"", 0, "some/path", "foo", "http://foo/some/path"},
+		{"", 0, "/some/path", "foo", "http://foo/some/path"},
+		{"https://", 0, "", "foo", "https://foo"},
+		{"https://", 80, "", "foo", "https://foo:80"},
+		{"https://", 0, "some/path", "foo", "https://foo/some/path"},
+		{"https://", 0, "", "http://foo", "http://foo"}, // specified scheme beats default...
+		{"", 9999, "", "foo:80", "http://foo:80"},       // specified port beats default...
+		{"", 0, "/bar", "foo/baz", "http://foo/bar"},    // ...but default path beats specified!
+	} {
+		if want, have := input.want, sanitize.URL(input.scheme, input.port, input.path)(input.input); want != have {
+			t.Errorf("sanitize.URL(%q, %d, %q)(%q): want %q, have %q", input.scheme, input.port, input.path, input.input, want, have)
+			continue
+		}
+	}
+}

experimental/demoprobe/main.go

@@ -23,7 +23,7 @@ func main() {
 	)
 	flag.Parse()
 
-	publisher, err := xfer.NewHTTPPublisher(*publish, "demoprobe", "demoprobe")
+	_, publisher, err := xfer.NewHTTPPublisher(*publish, "demoprobe", "demoprobe")
 	if err != nil {
 		log.Fatal(err)
 	}

experimental/fixprobe/main.go

@@ -34,7 +34,7 @@ func main() {
 	}
 	f.Close()
 
-	publisher, err := xfer.NewHTTPPublisher(*publish, "fixprobe", "fixprobe")
+	_, publisher, err := xfer.NewHTTPPublisher(*publish, "fixprobe", "fixprobe")
 	if err != nil {
 		log.Fatal(err)
 	}

probe/main.go

@@ -80,16 +80,16 @@ func main() {
 		log.Printf("warning: process reporting enabled, but that requires root to find everything")
 	}
 
-	publisherFactory := func(target string) (xfer.Publisher, error) {
-		publisher, err := xfer.NewHTTPPublisher(target, *token, probeID)
+	factory := func(endpoint string) (string, xfer.Publisher, error) {
+		id, publisher, err := xfer.NewHTTPPublisher(endpoint, *token, probeID)
 		if err != nil {
-			return nil, err
+			return "", nil, err
 		}
-		return xfer.NewBackgroundPublisher(publisher), nil
+		return id, xfer.NewBackgroundPublisher(publisher), nil
 	}
-	publishers := xfer.NewMultiPublisher(publisherFactory)
+	publishers := xfer.NewMultiPublisher(factory)
 	defer publishers.Stop()
-	resolver := newStaticResolver(targets, publishers.Add)
+	resolver := newStaticResolver(targets, publishers.Set)
 	defer resolver.Stop()
 
 	addrs, err := net.InterfaceAddrs()
@@ -133,10 +133,7 @@ func main() {
 	}
 
 	if *weaveRouterAddr != "" {
-		weave, err := overlay.NewWeave(hostID, *weaveRouterAddr)
-		if err != nil {
-			log.Fatalf("failed to start Weave tagger: %v", err)
-		}
+		weave := overlay.NewWeave(hostID, *weaveRouterAddr)
 		tickers = append(tickers, weave)
 		taggers = append(taggers, weave)
 		reporters = append(reporters, weave)

probe/overlay/weave.go

@@ -5,14 +5,13 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
-	"net"
 	"net/http"
-	"net/url"
 	"regexp"
 	"strings"
 	"sync"
 
 	"github.com/weaveworks/scope/common/exec"
+	"github.com/weaveworks/scope/common/sanitize"
 	"github.com/weaveworks/scope/probe/docker"
 	"github.com/weaveworks/scope/report"
 )
@@ -68,15 +67,11 @@ type weaveStatus struct {
 
 // NewWeave returns a new Weave tagger based on the Weave router at
 // address. The address should be an IP or FQDN, no port.
-func NewWeave(hostID, weaveRouterAddress string) (*Weave, error) {
-	s, err := sanitize("http://", 6784, "/report")(weaveRouterAddress)
-	if err != nil {
-		return nil, err
-	}
+func NewWeave(hostID, weaveRouterAddress string) *Weave {
 	return &Weave{
-		url:    s,
+		url:    sanitize.URL("http://", 6784, "/report")(weaveRouterAddress),
 		hostID: hostID,
-	}, nil
+	}
 }
 
 // Tick implements Ticker
@@ -202,25 +197,3 @@ func (w *Weave) Report() (report.Report, error) {
 	}
 	return r, nil
 }
-
-func sanitize(scheme string, port int, path string) func(string) (string, error) {
-	return func(s string) (string, error) {
-		if s == "" {
-			return "", fmt.Errorf("no host")
-		}
-		if !strings.HasPrefix(s, "http") {
-			s = scheme + s
-		}
-		u, err := url.Parse(s)
-		if err != nil {
-			return "", err
-		}
-		if _, _, err = net.SplitHostPort(u.Host); err != nil {
-			u.Host += fmt.Sprintf(":%d", port)
-		}
-		if u.Path != path {
-			u.Path = path
-		}
-		return u.String(), nil
-	}
-}

probe/overlay/weave_test.go

@@ -25,11 +25,7 @@ func TestWeaveTaggerOverlayTopology(t *testing.T) {
 	s := httptest.NewServer(http.HandlerFunc(mockWeaveRouter))
 	defer s.Close()
 
-	w, err := overlay.NewWeave(mockHostID, s.URL)
-	if err != nil {
-		t.Fatal(err)
-	}
-
+	w := overlay.NewWeave(mockHostID, s.URL)
 	w.Tick()
 
 	{

probe/resolver.go

@@ -16,92 +16,96 @@ var (
 )
 
 type staticResolver struct {
-	quit  chan struct{}
-	add   func(string)
-	peers []peer
+	set     func(string, []string)
+	targets []target
+	quit    chan struct{}
 }
 
-type peer struct {
-	hostname string
-	port     string
-}
+type target struct{ host, port string }
+
+func (t target) String() string { return net.JoinHostPort(t.host, t.port) }
 
-// NewResolver starts a new resolver that periodically
-// tries to resolve peers and the calls add() with all the
-// resolved IPs.  It explictiy supports hostnames which
-// resolve to multiple IPs; it will repeatedly call
-// add with the same IP, expecting the target to dedupe.
-func newStaticResolver(peers []string, add func(string)) staticResolver {
+// newStaticResolver periodically resolves the targets, and calls the set
+// function with all the resolved IPs. It explictiy supports targets which
+// resolve to multiple IPs.
+func newStaticResolver(targets []string, set func(target string, endpoints []string)) staticResolver {
 	r := staticResolver{
-		quit:  make(chan struct{}),
-		add:   add,
-		peers: prepareNames(peers),
+		targets: prepare(targets),
+		set:     set,
+		quit:    make(chan struct{}),
 	}
 	go r.loop()
 	return r
 }
 
-func prepareNames(strs []string) []peer {
-	var results []peer
-	for _, s := range strs {
-		var (
-			hostname string
-			port     string
-		)
-
-		if strings.Contains(s, ":") {
-			var err error
-			hostname, port, err = net.SplitHostPort(s)
-			if err != nil {
-				log.Printf("invalid address %s: %v", s, err)
-				continue
-			}
-		} else {
-			hostname, port = s, strconv.Itoa(xfer.AppPort)
-		}
-
-		results = append(results, peer{hostname, port})
-	}
-	return results
-}
-
 func (r staticResolver) loop() {
-	r.resolveHosts()
+	r.resolve()
 	t := tick(time.Minute)
 	for {
 		select {
 		case <-t:
-			r.resolveHosts()
-
+			r.resolve()
 		case <-r.quit:
 			return
 		}
 	}
 }
 
-func (r staticResolver) resolveHosts() {
-	for _, peer := range r.peers {
-		var addrs []net.IP
-		if addr := net.ParseIP(peer.hostname); addr != nil {
-			addrs = []net.IP{addr}
-		} else {
+func (r staticResolver) Stop() {
+	close(r.quit)
+}
+
+func prepare(strs []string) []target {
+	var targets []target
+	for _, s := range strs {
+		var host, port string
+		if strings.Contains(s, ":") {
 			var err error
-			addrs, err = lookupIP(peer.hostname)
+			host, port, err = net.SplitHostPort(s)
 			if err != nil {
+				log.Printf("invalid address %s: %v", s, err)
 				continue
 			}
+		} else {
+			host, port = s, strconv.Itoa(xfer.AppPort)
 		}
+		targets = append(targets, target{host, port})
+	}
+	return targets
+}
 
-		for _, addr := range addrs {
-			// For now, ignore IPv6
-			if addr.To4() == nil {
-				continue
-			}
-			r.add(net.JoinHostPort(addr.String(), peer.port))
-		}
+func (r staticResolver) resolve() {
+	for t, endpoints := range resolveMany(r.targets) {
+		r.set(t.String(), endpoints)
 	}
 }
 
-func (r staticResolver) Stop() {
-	close(r.quit)
+func resolveMany(targets []target) map[target][]string {
+	result := map[target][]string{}
+	for _, t := range targets {
+		result[t] = resolveOne(t)
+	}
+	return result
+}
+
+func resolveOne(t target) []string {
+	var addrs []net.IP
+	if addr := net.ParseIP(t.host); addr != nil {
+		addrs = []net.IP{addr}
+	} else {
+		var err error
+		addrs, err = lookupIP(t.host)
+		if err != nil {
+			return []string{}
+		}
+	}
+	endpoints := make([]string, 0, len(addrs))
+	for _, addr := range addrs {
+		// For now, ignore IPv6
+		if addr.To4() == nil {
+			continue
+		}
+		endpoints = append(endpoints, net.JoinHostPort(addr.String(), t.port))
+	}
+	return endpoints
 }