Make setting app info more extensible

pkg/secrethub/client.go

@@ -4,6 +4,7 @@ package secrethub
 
 import (
 	"os"
+	"regexp"
 	"runtime"
 	"strings"
 
@@ -52,6 +53,13 @@ type ClientInterface interface {
 
 var (
 	errClient = errio.Namespace("client")
+
+	whitelistAppInfoName = regexp.MustCompile("^[a-zA-Z0-9_-]*$")
+)
+
+// Errors
+var (
+	ErrInvalidAppInfoName = errClient.Code("invalid_app_info_name").Error("name must be set and can only contain alphanumeric, underscore (_), and dash (-) characters")
 )
 
 // Client is a client for the SecretHub HTTP API.
@@ -72,7 +80,7 @@ type Client struct {
 	// These are cached
 	repoIndexKeys map[api.RepoPath]*crypto.SymmetricKey
 
-	appInfo   *AppInfo
+	appInfo   []*AppInfo
 	ConfigDir *configdir.Dir
 }
 
@@ -83,14 +91,23 @@ type AppInfo struct {
 	Version string
 }
 
-func (i AppInfo) userAgentSuffix() string {
+func (i AppInfo) userAgentComponent() string {
 	res := i.Name
 	if i.Version != "" {
 		res += "/" + strings.TrimPrefix(i.Version, "v")
 	}
 	return res
 }
 
+// ValidateName returns an error if the provided app name is not set or doesn't match alphanumeric, underscore (_), and dash (-) characters.
+func (i AppInfo) ValidateName() error {
+	if i.Name == "" || !whitelistAppInfoName.MatchString(i.Name) {
+		return ErrInvalidAppInfoName
+	}
+
+	return nil
+}
+
 // NewClient creates a new SecretHub client. Provided options are applied to the client.
 //
 // If no WithCredentials() option is provided, the client tries to find a key credential at the following locations (in order):
@@ -102,6 +119,7 @@ func NewClient(with ...ClientOption) (*Client, error) {
 	client := &Client{
 		httpClient:    http.NewClient(),
 		repoIndexKeys: make(map[api.RepoPath]*crypto.SymmetricKey),
+		appInfo:       []*AppInfo{},
 	}
 	err := client.with(with...)
 	if err != nil {
@@ -139,6 +157,19 @@ func NewClient(with ...ClientOption) (*Client, error) {
 		}
 	}
 
+	appName := os.Getenv("SECRETHUB_APP_INFO_NAME")
+	if appName != "" {
+		appVersion := os.Getenv("SECRETHUB_APP_INFO_VERSION")
+		topLevelAppInfo := &AppInfo{
+			Name:    appName,
+			Version: appVersion,
+		}
+		// Ignore app info from environment variable if name is invalid
+		if err = topLevelAppInfo.ValidateName(); err == nil {
+			client.appInfo = append(client.appInfo, topLevelAppInfo)
+		}
+	}
+
 	userAgent := client.userAgent()
 
 	client.httpClient.Options(http.WithUserAgent(userAgent))
@@ -235,8 +266,8 @@ func (c *Client) DefaultCredential() credentials.Reader {
 
 func (c *Client) userAgent() string {
 	userAgent := userAgentPrefix
-	if c.appInfo != nil {
-		userAgent += " " + c.appInfo.userAgentSuffix()
+	for _, info := range c.appInfo {
+		userAgent += " " + info.userAgentComponent()
 	}
 	osName, err := operatingsystem.GetOperatingSystem()
 	if err != nil {

pkg/secrethub/client_options.go

@@ -1,7 +1,6 @@
 package secrethub
 
 import (
-	"errors"
 	"net/http"
 	"net/url"
 	"time"
@@ -51,10 +50,10 @@ func WithTransport(transport http.RoundTripper) ClientOption {
 // WithAppInfo sets the AppInfo to be used for identifying the application that is using the SecretHub Client.
 func WithAppInfo(appInfo *AppInfo) ClientOption {
 	return func(c *Client) error {
-		if appInfo.Name == "" {
-			return errors.New("name must be set for AppInfo")
+		if err := appInfo.ValidateName(); err != nil {
+			return err
 		}
-		c.appInfo = appInfo
+		c.appInfo = append(c.appInfo, appInfo)
 		return nil
 	}
 }

pkg/secrethub/client_test.go

@@ -0,0 +1,74 @@
+package secrethub
+
+import (
+	"os"
+	"regexp"
+	"testing"
+
+	"github.com/secrethub/secrethub-go/internals/assert"
+)
+
+func TestClient_userAgent(t *testing.T) {
+	cases := map[string]struct {
+		appInfo       []*AppInfo
+		envAppName    string
+		envAppVersion string
+		expected      string
+		err           error
+	}{
+		"default": {},
+		"multiple app info layers": {
+			appInfo: []*AppInfo{
+				{Name: "secrethub-xgo", Version: "0.1.0"},
+				{Name: "secrethub-java", Version: "0.2.0"},
+			},
+			expected: "secrethub-xgo/0.1.0 secrethub-java/0.2.0",
+		},
+		"top level app info from environment": {
+			appInfo: []*AppInfo{
+				{Name: "secrethub-cli", Version: "0.37.0"},
+			},
+			envAppName:    "secrethub-circleci-orb",
+			envAppVersion: "1.0.0",
+			expected:      "secrethub-cli/0.37.0 secrethub-circleci-orb/1.0.0",
+		},
+		"invalid app name": {
+			appInfo: []*AppInfo{
+				{Name: "illegal-name*%!@", Version: "0.1.0"},
+			},
+			err: ErrInvalidAppInfoName,
+		},
+		"ignore faulty environment variable": {
+			appInfo: []*AppInfo{
+				{Name: "secrethub-cli", Version: "0.37.0"},
+			},
+			envAppName: "illegal-name*%!@",
+			expected:   "secrethub-cli/0.37.0",
+		},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			os.Setenv("SECRETHUB_APP_INFO_NAME", tc.envAppName)
+			os.Setenv("SECRETHUB_APP_INFO_VERSION", tc.envAppVersion)
+
+			var opts []ClientOption
+			for _, info := range tc.appInfo {
+				opts = append(opts, WithAppInfo(info))
+			}
+			client, err := NewClient(opts...)
+			assert.Equal(t, err, tc.err)
+			if err != nil {
+				return
+			}
+
+			userAgent := client.userAgent()
+			pattern := tc.expected + " \\(.*\\)"
+			matched, err := regexp.MatchString(pattern, userAgent)
+			assert.OK(t, err)
+			if !matched {
+				t.Errorf("user agent '%s' doesn't match pattern '%s'", userAgent, pattern)
+			}
+		})
+	}
+}