Allow for both a random schema name and a time-based one

Author: Photonios

docs/source/schemas.rst

@@ -73,14 +73,32 @@ Re-create if necessary with a custom name
    schema = PostgresSchema.drop_and_create("otherschema", cascade=True)
 
 
+With a time-based name
+**********************
+
+.. warning::
+
+   The time-based suffix is precise up to the second. If two threads or processes both try to create a time-based schema name with the same suffix in the same second, they will have conflicts.
+
+.. code-block:: python
+
+   for psqlextra.schema import PostgresSchema
+
+   # schema name will be "myprefix_<timestamp>"
+   schema = PostgresSchema.create_time_based("myprefix")
+   print(schema.name)
+
+
 With a random name
 ******************
 
+A 8 character suffix is appended. Entropy is dependent on your system. See :meth:`~os.urandom` for more information.
+
 .. code-block:: python
 
    for psqlextra.schema import PostgresSchema
 
-   # schema name will be "myprefix_<timestamp>"
+   # schema name will be "myprefix_<8 random characters>"
    schema = PostgresSchema.create_random("myprefix")
    print(schema.name)
 

psqlextra/schema.py

@@ -1,3 +1,5 @@
+import os
+
 from contextlib import contextmanager
 
 import wrapt
@@ -84,10 +86,14 @@ def create(
         return cls(name, using=using)
 
     @classmethod
-    def create_random(
+    def create_time_based(
         cls, prefix: str, *, using: str = DEFAULT_DB_ALIAS
     ) -> "PostgresSchema":
-        """Creates a new schema with a random (time-based) suffix.
+        """Creates a new schema with a time-based suffix.
+
+        The time is precise up to the second. Creating
+        multiple time based schema in the same second
+        WILL lead to conflicts.
 
         Arguments:
             prefix:
@@ -101,6 +107,24 @@ def create_random(
         name_suffix = timezone.now().strftime("%Y%m%d%H%m%s")
         return cls.create(f"{prefix}_{name_suffix}", using=using)
 
+    @classmethod
+    def create_random(
+        cls, prefix: str, *, using: str = DEFAULT_DB_ALIAS
+    ) -> "PostgresSchema":
+        """Creates a new schema with a random suffix.
+
+        Arguments:
+            prefix:
+                Name to prefix the final name with. The name plus
+                prefix cannot be longer than 63 characters.
+
+            using:
+                Name of the database connection to use.
+        """
+
+        name_suffix = os.urandom(4).hex()
+        return cls.create(f"{prefix}_{name_suffix}", using=using)
+
     @classmethod
     def delete_and_create(
         cls, name: str, *, cascade: bool = False, using: str = DEFAULT_DB_ALIAS

tests/test_schema.py

@@ -52,14 +52,24 @@ def test_postgres_schema_create_name_that_requires_escaping():
     assert _does_schema_exist("table")
 
 
-def test_postgres_schema_create_random():
+def test_postgres_schema_create_time_based():
     with freezegun.freeze_time("2023-04-07 13:37:00.0"):
-        schema = PostgresSchema.create_random("myprefix")
+        schema = PostgresSchema.create_time_based("myprefix")
 
     assert schema.name == "myprefix_2023040713041680892620"
     assert _does_schema_exist(schema.name)
 
 
+def test_postgres_schema_create_random():
+    schema = PostgresSchema.create_random("myprefix")
+
+    prefix, suffix = schema.name.split("_")
+    assert prefix == "myprefix"
+    assert len(suffix) == 8
+
+    assert _does_schema_exist(schema.name)
+
+
 def test_postgres_schema_delete_and_create():
     schema = PostgresSchema.create("test")
 
@@ -215,11 +225,12 @@ def test_postgres_schema_connection_no_delete_default():
 
 
 def test_postgres_temporary_schema():
-    with freezegun.freeze_time("2023-04-07 13:37:00.0"):
-        with postgres_temporary_schema("temp") as schema:
-            assert schema.name == "temp_2023040713041680892620"
+    with postgres_temporary_schema("temp") as schema:
+        name_prefix, name_suffix = schema.name.split("_")
+        assert name_prefix == "temp"
+        assert len(name_suffix) == 8
 
-            assert _does_schema_exist(schema.name)
+        assert _does_schema_exist(schema.name)
 
     assert not _does_schema_exist(schema.name)