Add throttling data to message and API (#456)

* Add throttling data to message and API

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* workaround a false positive typing check

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

wlc/__init__.py

@@ -7,7 +7,7 @@
 import json
 import logging
 from copy import copy
-from typing import Any, ClassVar, Collection, Dict, Optional, Set, Tuple
+from typing import Any, ClassVar, Collection, Dict, Optional, Set, Tuple, cast
 from urllib.parse import urlencode, urlparse
 
 import dateutil.parser
@@ -37,6 +37,18 @@ def __init__(self, message: Optional[str] = None):
 class WeblateThrottlingError(WeblateException):
     """Throttling on the server."""
 
+    def __init__(self, limit: str, retry_after: str):
+        self.limit = limit
+        self.retry_after = retry_after
+        message_segments = [
+            cast(str, self.__doc__)
+        ]  # workaround for https://github.com/python/mypy/issues/15825
+        if limit:
+            message_segments.append(f"Limit is {limit} requests.")
+        if retry_after:
+            message_segments.append(f"Retry after {retry_after} seconds.")
+        super().__init__(" ".join(message_segments))
+
 
 class WeblatePermissionError(WeblateException):
     """You don't have permission to access this object."""
@@ -114,7 +126,10 @@ def process_error(self, error):
             status_code = error.response.status_code
 
             if status_code == 429:
-                raise WeblateThrottlingError
+                headers = error.response.headers
+                raise WeblateThrottlingError(
+                    headers.get("X-RateLimit-Limit"), headers.get("Retry-After")
+                )
             if status_code == 404:
                 raise WeblateException(
                     "Object not found on the server "

wlc/test_base.py

@@ -207,7 +207,11 @@ def register_uris():
         method=responses.POST,
         json={"detail": "Can not create components"},
     )
-    register_error("projects/throttled", 429)
+    register_error(
+        "projects/throttled",
+        429,
+        headers={"X-RateLimit-Limit": "100", "Retry-After": "81818"},
+    )
     register_error("projects/error", 500)
     register_error("projects/io", 500, callback=raise_error)
     register_error("projects/bug", 500, callback=raise_error)

wlc/test_wlc.py

@@ -50,7 +50,10 @@ def test_denied_json(self):
 
     def test_throttled(self):
         """Test listing projects."""
-        with self.assertRaisesRegex(WeblateException, "Throttling"):
+        with self.assertRaisesRegex(
+            WeblateException,
+            "Throttling.*Limit is 100 requests. Retry after 81818 seconds.",
+        ):
             Weblate().get_object("throttled")
 
     def test_error(self):