Add plugin user-agent helper (#5039)

helper/useragent/useragent.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"runtime"
 
+	"github.com/hashicorp/vault/logical"
 	"github.com/hashicorp/vault/version"
 )
 
@@ -23,7 +24,24 @@ var (
 )
 
 // String returns the consistent user-agent string for Vault.
+//
+// e.g. Vault/0.10.4 (+https://www.vaultproject.io/; go1.10.1)
 func String() string {
 	return fmt.Sprintf("Vault/%s (+%s; %s)",
 		versionFunc(), projectURL, rt)
 }
+
+// PluginString is usable by plugins to return a user-agent string reflecting
+// the running Vault version and an optional plugin name.
+//
+// e.g. Vault/0.10.4 (+https://www.vaultproject.io/; azure-auth; go1.10.1)
+func PluginString(env *logical.PluginEnvironment, pluginName string) string {
+	var name string
+
+	if pluginName != "" {
+		name = pluginName + "; "
+	}
+
+	return fmt.Sprintf("Vault/%s (+%s; %s%s)",
+		env.VaultVersion, projectURL, name, rt)
+}

helper/useragent/useragent_test.go

@@ -2,6 +2,8 @@ package useragent
 
 import (
 	"testing"
+
+	"github.com/hashicorp/vault/logical"
 )
 
 func TestUserAgent(t *testing.T) {
@@ -16,3 +18,27 @@ func TestUserAgent(t *testing.T) {
 		t.Errorf("expected %q to be %q", act, exp)
 	}
 }
+
+func TestUserAgentPlugin(t *testing.T) {
+	projectURL = "https://vault-test.com"
+	rt = "go5.0"
+	env := &logical.PluginEnvironment{
+		VaultVersion: "1.2.3",
+	}
+	pluginName := "azure-auth"
+
+	act := PluginString(env, pluginName)
+
+	exp := "Vault/1.2.3 (+https://vault-test.com; azure-auth; go5.0)"
+	if exp != act {
+		t.Errorf("expected %q to be %q", act, exp)
+	}
+
+	pluginName = ""
+	act = PluginString(env, pluginName)
+
+	exp = "Vault/1.2.3 (+https://vault-test.com; go5.0)"
+	if exp != act {
+		t.Errorf("expected %q to be %q", act, exp)
+	}
+}