Adding check that domain is resolved locally for cert management

locales/en.json

@@ -253,6 +253,7 @@
     "certmanager_domain_http_not_working": "It seems that the domain {domain:s} cannot be accessed through HTTP. Please check your DNS and nginx configuration is okay",
     "certmanager_error_no_A_record": "No DNS 'A' record found for {domain:s}. You need to make your domain name point to your machine to be able to install a Let's Encrypt certificate! (If you know what you are doing, use --no-checks to disable those checks.)",
     "certmanager_domain_dns_ip_differs_from_public_ip": "The DNS 'A' record for domain {domain:s} is different from this server IP. If you recently modified your A record, please wait for it to propagate (some DNS propagation checkers are available online). (If you know what you are doing, use --no-checks to disable those checks.)",
+    "certmanager_domain_not_resolved_locally": "The domain {domain:s} cannot be resolved locally. This might happen if you recently modified your DNS record. If so, please wait a few hours for it to propagate. If the issue persists, consider adding {domain:s} to /etc/hosts. (If you know what you are doing, use --no-checks to disable those checks.)",
     "certmanager_cannot_read_cert": "Something wrong happened when trying to open current certificate for domain {domain:s} (file: {file:s}), reason: {reason:s}",
     "certmanager_cert_install_success_selfsigned": "Successfully installed a self-signed certificate for domain {domain:s}!",
     "certmanager_cert_install_success": "Successfully installed Let's Encrypt certificate for domain {domain:s}!",

src/yunohost/certificate.py

@@ -785,6 +785,13 @@ def _check_domain_is_ready_for_ACME(domain):
         raise MoulinetteError(errno.EINVAL, m18n.n(
             'certmanager_domain_http_not_working', domain=domain))
 
+    # Check if domain is resolved locally (Might happen despite the previous
+    # checks because of dns propagation ?... Acme-tiny won't work in that case,
+    # because it explicitly requests() the domain.)
+    if not _domain_is_resolved_locally(domain):
+        raise MoulinetteError(errno.EINVAL, m18n.n(
+            'certmanager_domain_not_resolved_locally', domain=domain))
+
 
 def _dns_ip_match_public_ip(public_ip, domain):
     try:
@@ -809,6 +816,15 @@ def _domain_is_accessible_through_HTTP(ip, domain):
     return True
 
 
+def _domain_is_resolved_locally(domain):
+    try:
+        requests.head("http://%s/" % domain)
+    except Exception:
+        return False
+
+    return True
+
+
 def _name_self_CA():
     ca_conf = os.path.join(SSL_DIR, "openssl.ca.cnf")