feat(postgres): Remove SqlAlchemy dependency from postgres container

Create a new generic database subclass - DependencyFreeDbContainer
Remove test that was testing sqlalchemy support for driver types
Add tests for supported versions of Postgres
Modify the `get_connection_url` convenience method to support a
driverless url

Co-authored-by: Jason Turim <jason@opscanvas.com>
Co-authored-by: Jan Katins <jasc@gmx.net>

INDEX.rst

@@ -46,15 +46,31 @@ Getting Started
     >>> import sqlalchemy
 
     >>> with PostgresContainer("postgres:9.5") as postgres:
-    ...     engine = sqlalchemy.create_engine(postgres.get_connection_url())
+    ...     psql_url = postgres.get_connection_url()
+    ...     engine = sqlalchemy.create_engine(psql_url)
     ...     with engine.begin() as connection:
     ...         result = connection.execute(sqlalchemy.text("select version()"))
     ...         version, = result.fetchone()
     >>> version
-    'PostgreSQL 9.5...'
+    'PostgreSQL ......'
 
 The snippet above will spin up a postgres database in a container. The :code:`get_connection_url()` convenience method returns a :code:`sqlalchemy` compatible url we use to connect to the database and retrieve the database version.
 
+.. doctest::
+
+    >>> import asyncpg
+    >>> from testcontainers.postgres import PostgresContainer
+
+    >>> with PostgresContainer("postgres:9.5", driver=None) as postgres:
+    ...     psql_url = container.get_connection_url()
+    ...     with asyncpg.create_pool(dsn=psql_url,server_settings={"jit": "off"}) as pool:
+    ...         conn = await pool.acquire()
+    ...         ret = await conn.fetchval("SELECT 1")
+    ...         assert ret == 1
+
+This snippet does the same, however the driver is set to None, to influence the :code:`get_connection_url()` convenience method. Note, that the :code:`sqlalchemy` package is no longer a dependency to launch the Postgres container, so your project must provide support for the specified driver.
+
+
 Installation
 ------------
 

core/testcontainers/core/generic.py

@@ -26,6 +26,46 @@
     pass
 
 
+class DependencyFreeDbContainer(DockerContainer):
+    """
+    A generic database without any package dependencies
+    """
+
+    def start(self) -> "DbContainer":
+        self._configure()
+        super().start()
+        self._verify_status()
+        return self
+
+    def _verify_status(self) -> "DependencyFreeDbContainer":
+        """override this method to ensure the database is running and accepting connections"""
+        raise NotImplementedError
+
+    def _configure(self) -> None:
+        raise NotImplementedError
+
+    def _create_connection_url(
+        self,
+        dialect: str,
+        username: str,
+        password: str,
+        host: Optional[str] = None,
+        port: Optional[int] = None,
+        dbname: Optional[str] = None,
+        **kwargs,
+    ) -> str:
+        if raise_for_deprecated_parameter(kwargs, "db_name", "dbname"):
+            raise ValueError(f"Unexpected arguments: {','.join(kwargs)}")
+        if self._container is None:
+            raise ContainerStartException("container has not been started")
+        host = host or self.get_container_host_ip()
+        port = self.get_exposed_port(port)
+        url = f"{dialect}://{username}:{password}@{host}:{port}"
+        if dbname:
+            url = f"{url}/{dbname}"
+        return url
+
+
 class DbContainer(DockerContainer):
     """
     Generic database container.

modules/postgres/testcontainers/postgres/__init__.py

@@ -11,13 +11,16 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 import os
+from time import sleep
 from typing import Optional
 
-from testcontainers.core.generic import DbContainer
+from testcontainers.core.config import MAX_TRIES, SLEEP_TIME
+from testcontainers.core.generic import DependencyFreeDbContainer
 from testcontainers.core.utils import raise_for_deprecated_parameter
+from testcontainers.core.waiting_utils import wait_container_is_ready, wait_for_logs
 
 
-class PostgresContainer(DbContainer):
+class PostgresContainer(DependencyFreeDbContainer):
     """
     Postgres database container.
 
@@ -31,7 +34,7 @@ class PostgresContainer(DbContainer):
             >>> from testcontainers.postgres import PostgresContainer
             >>> import sqlalchemy
 
-            >>> postgres_container = PostgresContainer("postgres:9.5")
+            >>> postgres_container = PostgresContainer("postgres:16")
             >>> with postgres_container as postgres:
             ...     engine = sqlalchemy.create_engine(postgres.get_connection_url())
             ...     with engine.begin() as connection:
@@ -48,16 +51,16 @@ def __init__(
         username: Optional[str] = None,
         password: Optional[str] = None,
         dbname: Optional[str] = None,
-        driver: str = "psycopg2",
+        driver: str | None = "psycopg2",
         **kwargs,
     ) -> None:
         raise_for_deprecated_parameter(kwargs, "user", "username")
-        super().__init__(image=image, **kwargs)
-        self.username = username or os.environ.get("POSTGRES_USER", "test")
-        self.password = password or os.environ.get("POSTGRES_PASSWORD", "test")
-        self.dbname = dbname or os.environ.get("POSTGRES_DB", "test")
+        super(PostgresContainer, self).__init__(image=image, **kwargs)
+        self.username: str = username or os.environ.get("POSTGRES_USER", "test")
+        self.password: str = password or os.environ.get("POSTGRES_PASSWORD", "test")
+        self.dbname: str = dbname or os.environ.get("POSTGRES_DB", "test")
         self.port = port
-        self.driver = driver
+        self.driver = f"+{driver}" if driver else ""
 
         self.with_exposed_ports(self.port)
 
@@ -68,10 +71,25 @@ def _configure(self) -> None:
 
     def get_connection_url(self, host=None) -> str:
         return super()._create_connection_url(
-            dialect=f"postgresql+{self.driver}",
+            dialect=f"postgresql{self.driver}",
             username=self.username,
             password=self.password,
             dbname=self.dbname,
             host=host,
             port=self.port,
         )
+
+    @wait_container_is_ready()
+    def _verify_status(self) -> None:
+        wait_for_logs(self, ".*database system is ready to accept connections.*", MAX_TRIES, SLEEP_TIME)
+
+        count = 0
+        while count < MAX_TRIES:
+            status, _ = self.exec(f"pg_isready -hlocalhost -p{self.port} -U{self.username}")
+            if status == 0:
+                return
+
+            sleep(SLEEP_TIME)
+            count += 1
+
+        raise RuntimeError("Postgres could not get into a ready state")

modules/postgres/tests/test_postgres.py

@@ -1,21 +1,14 @@
-import sqlalchemy
-
 from testcontainers.postgres import PostgresContainer
 
 
 def test_docker_run_postgres():
-    postgres_container = PostgresContainer("postgres:9.5")
-    with postgres_container as postgres:
-        engine = sqlalchemy.create_engine(postgres.get_connection_url())
-        with engine.begin() as connection:
-            result = connection.execute(sqlalchemy.text("select version()"))
-            for row in result:
-                assert row[0].lower().startswith("postgresql 9.5")
+    # https://www.postgresql.org/support/versioning/
+    supported_versions = ["12", "13", "14", "15", "16", "latest"]
 
+    for version in supported_versions:
+        postgres_container = PostgresContainer(f"postgres:{version}")
+        with postgres_container as postgres:
+            status, msg = postgres.exec(f"pg_isready -hlocalhost -p{postgres.port} -U{postgres.username}")
 
-def test_docker_run_postgres_with_driver_pg8000():
-    postgres_container = PostgresContainer("postgres:9.5", driver="pg8000")
-    with postgres_container as postgres:
-        engine = sqlalchemy.create_engine(postgres.get_connection_url())
-        with engine.begin() as connection:
-            connection.execute(sqlalchemy.text("select 1=1"))
+            assert msg.decode("utf-8").endswith("accepting connections\n")
+            assert status == 0

pyproject.toml

@@ -102,7 +102,7 @@ neo4j = ["neo4j"]
 nginx = []
 opensearch = ["opensearch-py"]
 oracle = ["sqlalchemy", "cx_Oracle"]
-postgres = ["sqlalchemy", "psycopg2-binary"]
+postgres = []
 rabbitmq = ["pika"]
 redis = ["redis"]
 selenium = ["selenium"]