Add timeout & improve coverage

Looks like the NIST FTP server is not happy with urllib and it fails
(ugh!) by hanging for a long time. Maybe I'll have to delete it.
(it works with curl, which uses EPSV and not PASV. python uses PASV
for all ipv4 ftp and EPSV for ipv6, instead of trying EPSV first)

Set a reasonable timeout.

The format of `leapsecond sources` has been modified for better readability.

leapseconddata/__init__.py

@@ -260,6 +260,7 @@ class LeapSecondData:
         *,
         check_hash: bool = True,
         custom_sources: Sequence[str] = (),
+        timeout: float | None = 60,
     ) -> LeapSecondData:
         """Get the list of leap seconds from a standard source.
 
@@ -276,7 +277,7 @@ class LeapSecondData:
         for location in itertools.chain(custom_sources, cls.standard_file_sources, cls.standard_network_sources):
             logging.debug("Trying leap second data from %s", location)
             try:
-                candidate = cls.from_url(location, check_hash=check_hash)
+                candidate = cls.from_url(location, check_hash=check_hash, timeout=timeout)
             except InvalidHashError:
                 logging.warning("Invalid hash while reading %s", location)
                 continue
@@ -288,7 +289,7 @@ class LeapSecondData:
             if candidate.valid(when):
                 logging.info("Using leap second data from %s", location)
                 return candidate
-            logging.warning("Validity expired for %s", location)
+            logging.warning(f"Validity expired for {location} at {candidate.valid_until} (checking validity at {when})")
 
         raise ValidityError("No valid leap-second.list file could be found")
 
@@ -314,6 +315,7 @@ class LeapSecondData:
         url: str,
         *,
         check_hash: bool = True,
+        timeout: float | None = 60,
     ) -> LeapSecondData | None:
         """Retrieve the leap second list from a local file
 
@@ -321,7 +323,7 @@ class LeapSecondData:
         :param check_hash: Whether to check the embedded hash
         """
         try:
-            with urllib.request.urlopen(url) as open_file:
+            with urllib.request.urlopen(url, timeout=timeout) as open_file:
                 return cls.from_open_file(open_file, check_hash=check_hash)
         except urllib.error.URLError:  # pragma no cover
             return None

leapseconddata/__main__.py

@@ -166,27 +166,36 @@ def table(ctx: click.Context, *, start: datetime.datetime, end: datetime.datetim
 
 
 @cli.command
-def sources() -> None:
+@click.option("--timeout", type=float, default=12, metavar="[SECS]")
-    """Print information about leap-second.list data sources"""
+@click.argument("urls", type=str, nargs=-1)
+def sources(*, timeout: float, urls: list[str]) -> None:
+    """Print information about leap-second.list data sources
+
+    If no URLs are specified, print information about all standard sources.
+    If one or more URLs are specified, check them instead.
+    """
     first = True
-    for location in LeapSecondData.standard_file_sources + LeapSecondData.standard_network_sources:
+    locations = urls if urls else LeapSecondData.standard_file_sources + LeapSecondData.standard_network_sources
+    for location in locations:
         if not first:
             print()
         first = False
+        print(f"{location}:")
         try:
-            leap_second_data = LeapSecondData.from_url(location, check_hash=True)
+            leap_second_data = LeapSecondData.from_url(location, check_hash=True, timeout=timeout)
-        except InvalidHashError:  # pragma no coverage
+        except InvalidHashError as e:
-            print(f"{location}: Invalid hash")
+            print(f"    {e}")
-            leap_second_data = LeapSecondData.from_url(location, check_hash=False)
+            leap_second_data = LeapSecondData.from_url(location, check_hash=False, timeout=timeout)
-        except Exception as e:  # pragma no coverage # noqa: BLE001
+        except Exception as e:  # noqa: BLE001
-            print(f"{location}: {e}")
+            print(f"    {e}")
             leap_second_data = None
 
         if leap_second_data is not None:
-            print(f"{location}: Last updated {leap_second_data.last_updated}")
+            print(f"    Last updated {leap_second_data.last_updated}")
-            print(f"{location}: Valid until {leap_second_data.valid_until}")
+            print(f"    Valid until {leap_second_data.valid_until}")
+            print(f"    {len(leap_second_data.leap_seconds)} leap seconds")
         else:
-            print(f"{location}: Could not be read")
+            print("    Could not be read")
 
 
 if __name__ == "__main__":  # pragma no cover

testleapseconddata.py

@@ -18,10 +18,16 @@ import unittest
 import leapseconddata
 import leapseconddata.__main__
 
-db = leapseconddata.LeapSecondData.from_standard_source()
+db = leapseconddata.LeapSecondData.from_standard_source(timeout=8)
 
 GMT1 = datetime.timezone(datetime.timedelta(seconds=3600), "GMT1")
 
+bad_sources = [
+    "data:text/plain;base64,SGVsbG8sIFdvcmxkIQ==",
+    "data:text/plain,%23h%099dac5845%208acd32c0%202947d462%20daf4a943%20f58d9391%0A",
+    "file:///doesnotexist",
+]
+
 
 class LeapSecondDataTest(unittest.TestCase):
     def run_main(self, *args: str) -> None:
@@ -45,7 +51,8 @@ class LeapSecondDataTest(unittest.TestCase):
         self.run_main("next-leapsecond", "2100-2-2")
         self.run_main("previous-leapsecond", "2009-2-2")
         self.run_main("previous-leapsecond", "1960-2-2")
-        self.run_main("sources")
+        self.run_main("sources", "--timeout", "8")
+        self.run_main("sources", *bad_sources)
 
     def test_corrupt(self) -> None:
         self.assertRaises(
@@ -98,14 +105,7 @@ class LeapSecondDataTest(unittest.TestCase):
     def test_invalid2(self) -> None:
         when = datetime.datetime(datetime.MAXYEAR, 1, 1, tzinfo=datetime.timezone.utc) - datetime.timedelta(seconds=1)
         with self.assertRaises(leapseconddata.ValidityError):
-            leapseconddata.LeapSecondData.from_standard_source(
+            leapseconddata.LeapSecondData.from_standard_source(when, custom_sources=bad_sources, timeout=8)
-                when,
-                custom_sources=[
-                    "data:text/plain;base64,SGVsbG8sIFdvcmxkIQ==",
-                    "data:text/plain,%23h%099dac5845%208acd32c0%202947d462%20daf4a943%20f58d9391%0A",
-                    "file:///doesnotexist",
-                ],
-            )
 
     def test_tz(self) -> None:
         when = datetime.datetime(1999, 1, 1, tzinfo=datetime.timezone.utc) - datetime.timedelta(seconds=1)