Workaround for random Exchange/Office365 Server Unavailable IMAP errors

CHANGELOG.md

@@ -13,6 +13,7 @@ system path
 - Fall back to plain text SMTP if `--outgoing-ssl` is not used and `STARTTLS` 
 is not supported by the server
 - Always use `\n` as the newline when generating CSVs
+- Workaround for random Exchange/Office365 `Server Unavailable` IMAP errors
 
 3.9.7
 -----

parsedmarc/__init__.py

@@ -1524,8 +1524,28 @@ def watch_inbox(host, username, password, callback, reports_folder="INBOX",
         server.idle()
 
     except imapclient.exceptions.IMAPClientError as error:
-        error = error.__str__().lstrip("b'").rstrip("'").rstrip(".")
-        raise IMAPError(error)
+        error = error.__str__().replace("b'", "").replace("'", "")
+        # Workaround for random Exchange/Office365 IMAP errors
+        if "Server Unavailable. 15" in error:
+            logger.debug("IMAP error: {0}".format(error))
+            logger.debug("Reconnecting watcher")
+            server = imapclient.IMAPClient(host)
+            server.login(username, password)
+            server.select_folder(rf)
+            idle_start_time = time.monotonic()
+            ms = "MOVE" in get_imap_capabilities(server)
+            res = get_dmarc_reports_from_inbox(connection=server,
+                                               move_supported=ms,
+                                               reports_folder=rf,
+                                               archive_folder=af,
+                                               delete=delete,
+                                               test=test,
+                                               nameservers=ns,
+                                               dns_timeout=dt)
+            callback(res)
+            server.idle()
+        else:
+            raise IMAPError(error)
     except socket.gaierror:
         raise IMAPError("DNS resolution failed")
     except ConnectionRefusedError:

parsedmarc/cli.py

@@ -227,8 +227,7 @@ def _main():
             forensic_reports += reports["forensic_reports"]
 
         except IMAPError as error:
-            error_str = error.__str__().replace("b'", "").lstrip("'")
-            logger.error("IMAP Error: {0}".format(error_str))
+            logger.error("IMAP Error: {0}".format(error.__str__()))
             exit(1)
 
     results = OrderedDict([("aggregate_reports", aggregate_reports),
@@ -264,8 +263,7 @@ def _main():
                         test=args.test, nameservers=args.nameservers,
                         dns_timeout=args.timeout)
         except IMAPError as error:
-            error_str = error.__str__().replace("b'", "").lstrip("'")
-            logger.error("IMAP Error: {0}".format(error_str))
+            logger.error("IMAP Error: {0}".format(error.__str__()))
             exit(1)