chore: set User-Agent on all outgoing HTTP requests (#10867)

It's only polite, and it enables better troubleshooting in situations
like weird-ass requests to the upgrades download service.

---------

Signed-off-by: Jakob Borg <jakob@kastelo.net>

cmd/infra/stupgrades/main.go

@@ -224,7 +224,7 @@ func filterForLatest(rels []upgrade.Release) []upgrade.Release {
 	return filtered
 }
 
-var userAgentOSArchExp = regexp.MustCompile(`^syncthing.*\(.+ (\w+)-(\w+)\)$`)
+var userAgentOSArchExp = regexp.MustCompile(`^[Ss]yncthing.*\(.+ (\w+)-(\w+)\)$`)
 
 func filterForCompatibility(rels []upgrade.Release, ua, osv string) []upgrade.Release {
 	osArch := userAgentOSArchExp.FindStringSubmatch(ua)

cmd/syncthing/cli/client.go

@@ -18,6 +18,7 @@ import (
 	"net/http"
 	"strings"
 
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/events"
 	"github.com/syncthing/syncthing/lib/locations"
@@ -115,6 +116,7 @@ func (c *apiClient) Endpoint() string {
 
 func (c *apiClient) Do(req *http.Request) (*http.Response, error) {
 	req.Header.Set("X-Api-Key", c.apikey)
+	req.Header.Set("User-Agent", build.UserAgent())
 	resp, err := c.Client.Do(req)
 	if err != nil {
 		return nil, err

cmd/syncthing/crash_reporting.go

@@ -20,6 +20,7 @@ import (
 	"time"
 
 	"github.com/syncthing/syncthing/internal/slogutil"
+	"github.com/syncthing/syncthing/lib/build"
 )
 
 const (
@@ -81,6 +82,7 @@ func uploadPanicLog(ctx context.Context, urlBase, file string) error {
 	if err != nil {
 		return err
 	}
+	headReq.Header.Set("User-Agent", build.UserAgent())
 
 	// Set a reasonable timeout on the HEAD request
 	headCtx, headCancel := context.WithTimeout(ctx, headRequestTimeout)
@@ -101,6 +103,7 @@ func uploadPanicLog(ctx context.Context, urlBase, file string) error {
 	if err != nil {
 		return err
 	}
+	putReq.Header.Set("User-Agent", build.UserAgent())
 
 	// Set a reasonable timeout on the PUT request
 	putCtx, putCancel := context.WithTimeout(ctx, putRequestTimeout)

cmd/syncthing/main.go

@@ -374,6 +374,7 @@ func upgradeViaRest() error {
 	target := u.String()
 	r, _ := http.NewRequest(http.MethodPost, target, nil)
 	r.Header.Set("X-Api-Key", cfg.GUI().APIKey)
+	r.Header.Set("User-Agent", build.UserAgent())
 
 	tr := &http.Transport{
 		DialContext:     dialer.DialContext,
@@ -955,6 +956,7 @@ func (c browserCmd) Run() error {
 		if err != nil {
 			return err
 		}
+		req.Header.Set("User-Agent", build.UserAgent())
 		_, err = http.DefaultClient.Do(req) //nolint:bodyclose // we're exiting in a millisecond
 		if err != nil {
 			slog.Error("GUI not available", slogutil.Error(err))