etcdserver: stop using addScheme

This standardizes the flags to use a list of URLs everywhere. The next
step is to enforce the scheme based on TLS settings and support compat
flags.

pkg/flags/urls.go

@@ -0,0 +1,46 @@
+package flags
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+// URLs implements the flag.Value interface to allow users to define multiple
+// URLs on the command-line
+type URLs []url.URL
+
+// Set parses a command line set of URLs formatted like:
+// http://127.0.0.1:7001,http://10.1.1.2:80
+func (us *URLs) Set(s string) error {
+	strs := strings.Split(s, ",")
+	all := make([]url.URL, len(strs))
+	if len(all) == 0 {
+		return errors.New("no valid URLs given")
+	}
+	for _, in := range strs {
+		in = strings.TrimSpace(in)
+		u, err := url.Parse(in)
+		if err != nil {
+			return err
+		}
+		if u.Scheme != "http" && u.Scheme != "https" {
+			return fmt.Errorf("URL scheme must be http or https: %s", s)
+		}
+		if u.Path != "" {
+			return fmt.Errorf("URL must not contain a path: %s", s)
+		}
+		all = append(all, *u)
+	}
+	*us = all
+	return nil
+}
+
+func (us *URLs) String() string {
+	all := make([]string, len(*us))
+	for i, u := range *us {
+		all[i] = u.String()
+	}
+	return strings.Join(all, ",")
+}

pkg/flags/urls_test.go

@@ -0,0 +1,45 @@
+package flags
+
+import (
+	"testing"
+)
+
+func TestValidateURLsBad(t *testing.T) {
+	tests := []string{
+		// bad IP specification
+		":4001",
+		"127.0:8080",
+		"123:456",
+		// bad port specification
+		"127.0.0.1:foo",
+		"127.0.0.1:",
+		// unix sockets not supported
+		"unix://",
+		"unix://tmp/etcd.sock",
+		// bad strings
+		"somewhere",
+		"234#$",
+		"file://foo/bar",
+		"http://hello/asdf",
+	}
+	for i, in := range tests {
+		u := URLs{}
+		if err := u.Set(in); err == nil {
+			t.Errorf(`#%d: unexpected nil error for in=%q`, i, in)
+		}
+	}
+}
+
+func TestValidateURLsGood(t *testing.T) {
+	tests := []string{
+		"https://1.2.3.4:8080",
+		"http://10.1.1.1:80",
+		"http://10.1.1.1",
+	}
+	for i, in := range tests {
+		u := URLs{}
+		if err := u.Set(in); err != nil {
+			t.Errorf("#%d: err=%v, want nil for in=%q", i, err, in)
+		}
+	}
+}