feat: add Prefixer class to generate and parse resource names (#39)

test_utils/prefixer.py

@@ -0,0 +1,79 @@
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import datetime
+import random
+import re
+
+
+_RESOURCE_DATE_FORMAT = "%Y%m%d%H%M%S"
+_RESOURCE_DATE_LENGTH = 4 + 2 + 2 + 2 + 2 + 2
+_RE_SEPARATORS = re.compile(r"[/\-\\_]")
+
+
+def _common_prefix(repo, relative_dir, separator="_"):
+    repo = _RE_SEPARATORS.sub(separator, repo)
+    relative_dir = _RE_SEPARATORS.sub(separator, relative_dir)
+    return f"{repo}{separator}{relative_dir}"
+
+
+class Prefixer(object):
+    """Create/manage resource IDs for system testing.
+
+    Usage:
+
+    Creating resources:
+
+    >>> import test_utils.prefixer
+    >>> prefixer = test_utils.prefixer.Prefixer("python-bigquery", "samples/snippets")
+    >>> dataset_id = prefixer.create_prefix() + "my_sample"
+
+    Cleaning up resources:
+
+    >>> @pytest.fixture(scope="session", autouse=True)
+    ... def cleanup_datasets(bigquery_client: bigquery.Client):
+    ...     for dataset in bigquery_client.list_datasets():
+    ...         if prefixer.should_cleanup(dataset.dataset_id):
+    ...             bigquery_client.delete_dataset(
+    ...                 dataset, delete_contents=True, not_found_ok=True
+    """
+
+    def __init__(
+        self, repo, relative_dir, separator="_", cleanup_age=datetime.timedelta(days=1)
+    ):
+        self._separator = separator
+        self._cleanup_age = cleanup_age
+        self._prefix = _common_prefix(repo, relative_dir, separator=separator)
+
+    def create_prefix(self) -> str:
+        timestamp = datetime.datetime.utcnow().strftime(_RESOURCE_DATE_FORMAT)
+        random_string = hex(random.randrange(0x1000000))[2:]
+        return f"{self._prefix}{self._separator}{timestamp}{self._separator}{random_string}"
+
+    def _name_to_date(self, resource_name: str) -> datetime.datetime:
+        start_date = len(self._prefix) + len(self._separator)
+        date_string = resource_name[start_date : start_date + _RESOURCE_DATE_LENGTH]
+        try:
+            parsed_date = datetime.datetime.strptime(date_string, _RESOURCE_DATE_FORMAT)
+            return parsed_date
+        except ValueError:
+            return None
+
+    def should_cleanup(self, resource_name: str) -> bool:
+        yesterday = datetime.datetime.utcnow() - self._cleanup_age
+        if not resource_name.startswith(self._prefix):
+            return False
+
+        created_date = self._name_to_date(resource_name)
+        return created_date is not None and created_date < yesterday

tests/unit/test_prefixer.py

@@ -0,0 +1,89 @@
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import datetime
+import re
+
+import pytest
+
+import test_utils.prefixer
+
+
+class FakeDateTime(object):
+    """Fake datetime class since pytest can't monkeypatch attributes of
+    built-in/extension type.
+    """
+
+    def __init__(self, fake_now):
+        self._fake_now = fake_now
+
+    def utcnow(self):
+        return self._fake_now
+
+    strptime = datetime.datetime.strptime
+
+
+@pytest.mark.parametrize(
+    ("repo", "relative_dir", "separator", "expected"),
+    [
+        (
+            "python-bigquery",
+            "samples/snippets",
+            "_",
+            "python_bigquery_samples_snippets",
+        ),
+        ("python-storage", "samples\\snippets", "-", "python-storage-samples-snippets"),
+    ],
+)
+def test_common_prefix(repo, relative_dir, separator, expected):
+    got = test_utils.prefixer._common_prefix(repo, relative_dir, separator=separator)
+    assert got == expected
+
+
+def test_create_prefix(monkeypatch):
+    fake_datetime = FakeDateTime(datetime.datetime(2021, 6, 21, 3, 32, 0))
+    monkeypatch.setattr(datetime, "datetime", fake_datetime)
+
+    prefixer = test_utils.prefixer.Prefixer(
+        "python-test-utils", "tests/unit", separator="?"
+    )
+    got = prefixer.create_prefix()
+    parts = got.split("?")
+    assert len(parts) == 7
+    assert "?".join(parts[:5]) == "python?test?utils?tests?unit"
+    datetime_part = parts[5]
+    assert datetime_part == "20210621033200"
+    random_hex_part = parts[6]
+    assert re.fullmatch("[0-9a-f]+", random_hex_part)
+
+
+@pytest.mark.parametrize(
+    ("resource_name", "separator", "expected"),
+    [
+        ("test_utils_created_elsewhere", "_", False),
+        ("test_utils_20210620120000", "_", False),
+        ("test_utils_20210620120000_abcdef_my_name", "_", False),
+        ("test_utils_20210619120000", "_", True),
+        ("test_utils_20210619120000_abcdef_my_name", "_", True),
+        ("test?utils?created?elsewhere", "_", False),
+        ("test?utils?20210620120000", "?", False),
+        ("test?utils?20210619120000", "?", True),
+    ],
+)
+def test_should_cleanup(resource_name, separator, expected, monkeypatch):
+    fake_datetime = FakeDateTime(datetime.datetime(2021, 6, 21, 3, 32, 0))
+    monkeypatch.setattr(datetime, "datetime", fake_datetime)
+
+    prefixer = test_utils.prefixer.Prefixer("test", "utils", separator=separator)
+    assert prefixer.should_cleanup(resource_name) == expected