Add go-libipni user-agent header with version to HTTTP announce (#60)

- Replaces #58
- Fixes #59

announce/httpsender/option.go

@@ -4,13 +4,16 @@ import (
 	"fmt"
 	"net/http"
 	"time"
+
+	"github.com/ipni/go-libipni"
 )
 
 const defaultTimeout = time.Minute
 
 type config struct {
-	timeout time.Duration
-	client  *http.Client
+	timeout   time.Duration
+	client    *http.Client
+	userAgent string
 }
 
 // Option is a function that sets a value in a config.
@@ -19,7 +22,8 @@ type Option func(*config) error
 // getOpts creates a config and applies Options to it.
 func getOpts(opts []Option) (config, error) {
 	cfg := config{
-		timeout: defaultTimeout,
+		timeout:   defaultTimeout,
+		userAgent: "go-libipni/" + libipni.Release,
 	}
 	for i, opt := range opts {
 		if err := opt(&cfg); err != nil {
@@ -44,3 +48,11 @@ func WithClient(c *http.Client) Option {
 		return nil
 	}
 }
+
+// WithUserAgent sets the value used for the User-Agent header.
+func WithUserAgent(userAgent string) Option {
+	return func(cfg *config) error {
+		cfg.userAgent = userAgent
+		return nil
+	}
+}

announce/httpsender/sender.go

@@ -23,6 +23,7 @@ type Sender struct {
 	announceURLs []string
 	client       *http.Client
 	peerID       peer.ID
+	userAgent    string
 }
 
 // New creates a new Sender that sends announce messages over HTTP. Announce
@@ -69,6 +70,7 @@ func New(announceURLs []*url.URL, peerID peer.ID, options ...Option) (*Sender, e
 		announceURLs: urls,
 		client:       client,
 		peerID:       peerID,
+		userAgent:    opts.userAgent,
 	}, nil
 }
 
@@ -165,6 +167,7 @@ func (s *Sender) sendAnnounce(ctx context.Context, announceURL string, buf *byte
 	if err != nil {
 		return err
 	}
+	req.Header.Set("User-Agent", s.userAgent)
 	if js {
 		req.Header.Set("Content-Type", "application/json")
 	} else {

announce/httpsender/sender_test.go

@@ -52,6 +52,9 @@ func init() {
 func TestSend(t *testing.T) {
 	var count int
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Check for expected User-Agent
+		require.True(t, strings.HasPrefix(r.UserAgent(), "go-libipni/"))
+
 		// Decode CID and originator addresses from message.
 		an := message.Message{}
 		err := an.UnmarshalCBOR(r.Body)

version.go

@@ -0,0 +1,41 @@
+package libipni
+
+import (
+	_ "embed"
+	"encoding/json"
+	"runtime/debug"
+)
+
+var (
+	// Release is the release version tag value, e.g. "v1.2.3"
+	Release string
+	// Revision is the git commit hash.
+	Revision string
+	// Version is the full version string: Release-Revision.
+	Version string
+)
+
+//go:embed version.json
+var versionJSON []byte
+
+func init() {
+	// Read version from embedded JSON file.
+	var verMap map[string]string
+	json.Unmarshal(versionJSON, &verMap)
+	Release = verMap["version"]
+
+	// If running from a module, try to get the build info.
+	bi, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+
+	// Append the revision to the version.
+	for i := range bi.Settings {
+		if bi.Settings[i].Key == "vcs.revision" {
+			Revision = bi.Settings[i].Value
+			Version = Release + "-" + Revision
+			break
+		}
+	}
+}