Add a helper for generating Consul's user-agent string

agent/retry_join.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/hashicorp/consul/lib"
 	discover "github.com/hashicorp/go-discover"
 )
 
@@ -67,7 +68,11 @@ func (r *retryJoiner) retryJoin() error {
 		return nil
 	}
 
-	disco := discover.Discover{}
+	disco, err := discover.New(discover.WithUserAgent(lib.UserAgent()))
+	if err != nil {
+		return err
+	}
+
 	r.logger.Printf("[INFO] agent: Retry join %s is supported for: %s", r.cluster, strings.Join(disco.Names(), " "))
 	r.logger.Printf("[INFO] agent: Joining %s cluster...", r.cluster)
 	attempt := 0

agent/retry_join_test.go

@@ -8,7 +8,10 @@ import (
 )
 
 func TestGoDiscoverRegistration(t *testing.T) {
-	d := discover.Discover{}
+	d, err := discover.New()
+	if err != nil {
+		t.Fatal(err)
+	}
 	got := d.Names()
 	want := []string{"aliyun", "aws", "azure", "digitalocean", "gce", "os", "scaleway", "softlayer", "triton"}
 	if !reflect.DeepEqual(got, want) {

lib/useragent.go

@@ -0,0 +1,29 @@
+package lib
+
+import (
+	"fmt"
+	"runtime"
+
+	"github.com/hashicorp/consul/version"
+)
+
+var (
+	// projectURL is the project URL.
+	projectURL = "https://www.consul.io/"
+
+	// rt is the runtime - variable for tests.
+	rt = runtime.Version()
+
+	// versionFunc is the func that returns the current version. This is a
+	// function to take into account the different build processes and distinguish
+	// between enterprise and oss builds.
+	versionFunc = func() string {
+		return version.GetHumanVersion()
+	}
+)
+
+// UserAgent returns the consistent user-agent string for Consul.
+func UserAgent() string {
+	return fmt.Sprintf("Consul/%s (+%s; %s)",
+		versionFunc(), projectURL, rt)
+}

lib/useragent_test.go

@@ -0,0 +1,18 @@
+package lib
+
+import (
+	"testing"
+)
+
+func TestUserAgent(t *testing.T) {
+	projectURL = "https://consul-test.com"
+	rt = "go5.0"
+	versionFunc = func() string { return "1.2.3" }
+
+	act := UserAgent()
+
+	exp := "Consul/1.2.3 (+https://consul-test.com; go5.0)"
+	if exp != act {
+		t.Errorf("expected %q to be %q", act, exp)
+	}
+}