common/sanitize + relevant updates

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

@@ -81,7 +81,7 @@ func main() {
 	}
 
 	publisherFactory := func(target string) (xfer.Publisher, error) {
-		publisher, err := xfer.NewHTTPPublisher(target, *token, probeID)
+		_, publisher, err := xfer.NewHTTPPublisher(target, *token, probeID)
 		if err != nil {
 			return nil, err
 		}
@@ -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

@@ -5,13 +5,13 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
-	"net"
 	"net/http"
-	"net/url"
 	"regexp"
 	"strings"
 	"sync"
 
+	"github.com/weaveworks/scope/common/sanitize"
+
 	"github.com/weaveworks/scope/common/exec"
 	"github.com/weaveworks/scope/probe/docker"
 	"github.com/weaveworks/scope/report"
@@ -68,15 +68,11 @@ 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 +198,3 @@ 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()
 
 	{

xfer/publisher.go

@@ -2,13 +2,15 @@ package xfer
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"log"
 	"net/http"
-	"net/url"
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/weaveworks/scope/common/sanitize"
 )
 
 const (
@@ -17,7 +19,7 @@ const (
 )
 
 // Publisher is something which can send a buffered set of data somewhere,
-// probably to a collector.
+// probably to a remote collector.
 type Publisher interface {
 	Publish(*bytes.Buffer) error
 	Stop()
@@ -25,9 +27,9 @@ type Publisher interface {
 
 // HTTPPublisher publishes reports by POST to a fixed endpoint.
 type HTTPPublisher struct {
-	url   string
-	token string
-	id    string
+	url     string
+	token   string
+	probeID string
 }
 
 // ScopeProbeIDHeader is the header we use to carry the probe's unique ID. The
@@ -37,21 +39,23 @@ type HTTPPublisher struct {
 const ScopeProbeIDHeader = "X-Scope-Probe-ID"
 
 // NewHTTPPublisher returns an HTTPPublisher ready for use.
-func NewHTTPPublisher(target, token, id string) (*HTTPPublisher, error) {
-	if !strings.HasPrefix(target, "http") {
-		target = "http://" + target
-	}
-	u, err := url.Parse(target)
+func NewHTTPPublisher(target, token, probeID string) (string, *HTTPPublisher, error) {
+	targetAPI := sanitize.URL("http://", 0, "/api")(target)
+	resp, err := http.Get(targetAPI)
 	if err != nil {
-		return nil, err
+		return "", nil, err
 	}
-	if u.Path == "" {
-		u.Path = "/api/report"
+	defer resp.Body.Close()
+	var apiResponse struct {
+		ID string `json:"id"`
 	}
-	return &HTTPPublisher{
-		url:   u.String(),
-		token: token,
-		id:    id,
+	if err := json.NewDecoder(resp.Body).Decode(&apiResponse); err != nil {
+		return "", nil, err
+	}
+	return apiResponse.ID, &HTTPPublisher{
+		url:     sanitize.URL("http://", 0, "/api/report")(target),
+		token:   token,
+		probeID: probeID,
 	}, nil
 }
 
@@ -65,9 +69,8 @@ func (p HTTPPublisher) Publish(buf *bytes.Buffer) error {
 	if err != nil {
 		return err
 	}
-
 	req.Header.Set("Authorization", AuthorizationHeader(p.token))
-	req.Header.Set(ScopeProbeIDHeader, p.id)
+	req.Header.Set(ScopeProbeIDHeader, p.probeID)
 	req.Header.Set("Content-Encoding", "gzip")
 	// req.Header.Set("Content-Type", "application/binary") // TODO: we should use http.DetectContentType(..) on the gob'ed
 

xfer/publisher_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"compress/gzip"
 	"encoding/gob"
+	"encoding/json"
 	"net/http"
 	"net/http/httptest"
 	"reflect"
@@ -27,6 +28,11 @@ func TestHTTPPublisher(t *testing.T) {
 	)
 
 	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/api" {
+			json.NewEncoder(w).Encode(map[string]string{"id": "irrelevant"})
+			return
+		}
+
 		if want, have := xfer.AuthorizationHeader(token), r.Header.Get("Authorization"); want != have {
 			t.Errorf("want %q, have %q", want, have)
 		}
@@ -61,7 +67,7 @@ func TestHTTPPublisher(t *testing.T) {
 	s := httptest.NewServer(handlers.CompressHandler(handler))
 	defer s.Close()
 
-	p, err := xfer.NewHTTPPublisher(s.URL, token, id)
+	_, p, err := xfer.NewHTTPPublisher(s.URL, token, id)
 	if err != nil {
 		t.Fatal(err)
 	}