robustify nonce management by retry mechanismHEADmaster

1 files changed, 13 insertions, 4 deletions

diff --git a/acme_dns_tiny.py b/acme_dns_tiny.py
index 051e6ba..4903c63 100644
--- a/acme_dns_tiny.py
+++ b/acme_dns_tiny.py
@@ -177,17 +177,22 @@ class ACME:
         self.jwk_thumbprint = b64sha256(json.dumps(header['jwk'],
             sort_keys=True, separators=(',', ':')))
 
+    def request_new_nonce(self):
+        log.info('Request new nonce')
+        self.jws_header['nonce'] = requests.get(self.directory["newNonce"]
+                ).headers['Replay-Nonce']
+
     def init_sreqs(self, directory_url=None):
         self.generate_jws_header(self.account_key_path)
         log.info('Fetch information from the ACME directory.')
         self.directory = dirmap = requests.get(directory_url,
                 headers=self.dirheaders).json()
-        log.info('Request first nonce')
-        self.jws_header['nonce'] = requests.get(dirmap["newNonce"]
-                ).headers['Replay-Nonce']
+        self.request_new_nonce()
 
-    def sreq(self, url=None, payload=None, headers=None):
+    def sreq(self, url=None, payload=None, headers=None, max_retry=10):
         """Sends signed requests to ACME server."""
+        if max_retry < 0:
+            raise ValueError('max_retry exceeded')
         # POST-as-GET (payload=None != {}), payload64 is an empty string
         payload64   = '' if payload is None else b64json(payload)
         protected64 = b64json({**self.jws_header, 'url': url})
@@ -207,6 +212,10 @@ class ACME:
         with contextlib.suppress(ValueError):
             jmap = req.json()
         if req.status_code not in (200, 201):
+            if jmap['type'] == 'urn:ietf:params:acme:error:badNonce':
+                log.info('nonce expired or invalid, retry (left %d)', max_retry)
+                self.request_new_nonce()
+                return self.sreq(url, payload, headers, max_retry-1)
             raise ValueError(f'Request failed: {req.status_code} {jmap}, '
                 'hint: {sreq.headers.get("Link", "empty")}.')
         return collections.namedtuple('sreq', ['code', 'headers', 'map',