update certpool at server runtime - go

Question

Hi I am interested in adding certificates to the certPool while the server is running, but it seems like it's not picked up. Do I need to relaunch the server for this to work?
package main
import (
"crypto/tls"
"crypto/x509"
"fmt"
"io/ioutil"
"log"
"net/http"
)
func main() {
handler := http.NewServeMux()
// verify the cert if given (or check for jwt token)
handler.HandleFunc("/auth", func(w http.ResponseWriter, r *http.Request) {
if certs := r.TLS.PeerCertificates; len(certs) > 0 {
cert := certs[0]
fmt.Println(cert.Subject.CommonName)
w.WriteHeader(http.StatusOK)
fmt.Fprintln(w, "Cert Valid")
return
}
// ...
})
// the cert pool that holds the client CAs
certPool := x509.NewCertPool()
// post a new CA and add it to the pool
handler.HandleFunc("/ca", func(rw http.ResponseWriter, r *http.Request) {
caCertFile, err := ioutil.ReadAll(r.Body)
if err != nil {
log.Printf("error reading CA certificate: %v", err)
rw.WriteHeader(http.StatusUnprocessableEntity)
return
}
certPool.AppendCertsFromPEM(caCertFile)
rw.WriteHeader(http.StatusCreated)
})
server := http.Server{
Addr: ":9090",
Handler: handler,
TLSConfig: &tls.Config{
ClientAuth: tls.VerifyClientCertIfGiven,
ClientCAs: certPool,
MinVersion: tls.VersionTLS12,
},
}
if err := server.ListenAndServeTLS("certs/server/tls.crt", "certs/server/tls.key"); err != nil {
log.Fatalf("error listening to port: %v", err)
}
}
I am posting the cert with curl
curl -k -X POST https://localhost:9090/ca -d #test-ca.pem
Based, on one comment, I have tried the below but it doesn't seem to work either.
certFile, err := ioutil.ReadFile("certs/server/tls.crt")
if err != nil {
log.Fatal(err)
}
keyFile, err := ioutil.ReadFile("certs/server/tls.key")
if err != nil {
log.Fatal(err)
}
cert, err := tls.X509KeyPair(certFile, keyFile)
if err != nil {
log.Fatal(err)
}
listener, err := tls.Listen("tcp", ":9090", &tls.Config{
ClientAuth: tls.VerifyClientCertIfGiven,
ClientCAs: certPool,
Certificates: []tls.Certificate{cert},
})
if err != nil {
log.Fatalf("error creating listener: %v", err)
}
if err = http.Serve(listener, handler); err != nil {
log.Fatalf("error serving: %v", err)
}