Send helpful User-Agent string with all requests

cmd/certspotter/main.go

@@ -25,6 +25,7 @@ import (
 	"syscall"
 	"time"
 
+	"software.sslmate.com/src/certspotter/ctclient"
 	"software.sslmate.com/src/certspotter/loglist"
 	"software.sslmate.com/src/certspotter/monitor"
 )
@@ -139,6 +140,7 @@ func appendFunc(slice *[]string) func(string) error {
 
 func main() {
 	loglist.UserAgent = fmt.Sprintf("certspotter/%s (%s; %s; %s)", certspotterVersion(), runtime.Version(), runtime.GOOS, runtime.GOARCH)
+	ctclient.UserAgent = fmt.Sprintf("certspotter/%s (+https://github.com/SSLMate/certspotter)", certspotterVersion())
 
 	var flags struct {
 		batchSize   bool

ctclient/client.go

@@ -24,6 +24,8 @@ import (
 	"time"
 )
 
+var UserAgent = "software.sslmate.com/src/certspotter"
+
 // Create an HTTP client suitable for communicating with CT logs.  dialContext, if non-nil, is used for dialing.
 func NewHTTPClient(dialContext func(context.Context, string, string) (net.Conn, error)) *http.Client {
 	return &http.Client{
@@ -61,7 +63,7 @@ func get(ctx context.Context, httpClient *http.Client, fullURL string) ([]byte,
 	if err != nil {
 		return nil, err
 	}
-	request.Header.Set("User-Agent", "") // Don't send a User-Agent to make life harder for malicious logs
+	request.Header.Set("User-Agent", UserAgent)
 
 	if httpClient == nil {
 		httpClient = defaultHTTPClient

loglist/load.go

@@ -21,7 +21,7 @@ import (
 	"time"
 )
 
-var UserAgent = "certspotter"
+var UserAgent = "software.sslmate.com/src/certspotter"
 
 type ModificationToken struct {
 	etag     string