fix: Add memcached container (testcontainers#322)

Adding [Memcached](https://memcached.org/) container.

You have implemented a new container and would like to contribute it?
Great! Here are the necessary steps.

- [x] Create a new feature directory and populate it with the package
structure [described in the
documentation](https://testcontainers-python.readthedocs.io/en/latest/#package-structure).
Copying one of the existing features is likely the best way to get
started.
- [x] Implement the new feature (typically in `__init__.py`) and
corresponding tests.
- [x] Add a line `-e file:[feature name]` to `requirements.in` and run
`make requirements`. This command will find any new requirements and
generate lock files to ensure reproducible builds (see the [pip-tools
documentation](https://pip-tools.readthedocs.io/en/latest/) for
details). Then run `pip install -r requirements/[your python
version].txt` to install the new requirements.
- [x] Update the feature `README.rst` and add it to the table of
contents (`toctree` directive) in the top-level `README.rst`.
- [x] Add a line `[feature name]` to the list of components in the
GitHub Action workflow in `.github/workflows/main.yml` to run tests,
build, and publish your package when pushed to the `master` branch.
- [x] Rebase your development branch on `master` (or merge `master` into
your development branch).

Author: romulojales

index.rst

@@ -27,6 +27,7 @@ testcontainers-python facilitates the use of Docker containers for functional an
     modules/kafka/README
     modules/keycloak/README
     modules/localstack/README
+    modules/memcached/README
     modules/minio/README
     modules/mongodb/README
     modules/mssql/README

modules/memcached/README.rst

@@ -0,0 +1 @@
+.. autoclass:: testcontainers.memcached.MemcachedContainer

modules/memcached/setup.py

@@ -0,0 +1,17 @@
+from setuptools import find_namespace_packages, setup
+
+description = "Memcached component of testcontainers-python."
+
+setup(
+    name="testcontainers-memcached",
+    version="0.0.1rc1",
+    packages=find_namespace_packages(),
+    description=description,
+    long_description=description,
+    long_description_content_type="text/x-rst",
+    url="https://github.com/testcontainers/testcontainers-python",
+    install_requires=[
+        "testcontainers-core",
+    ],
+    python_requires=">=3.7",
+)

modules/memcached/testcontainers/memcached/__init__.py

@@ -0,0 +1,59 @@
+#
+#    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 socket
+
+from testcontainers.core.container import DockerContainer
+from testcontainers.core.waiting_utils import wait_container_is_ready
+
+
+class MemcachedNotReady(Exception):
+    pass
+
+
+class MemcachedContainer(DockerContainer):
+    """
+    Test container for Memcached. The example below spins up a Memcached server
+
+    Example:
+
+        .. doctest::
+
+            >>> from testcontainers.memcached import MemcachedContainer
+
+            >>> with MemcachedContainer() as memcached_container:
+            ...    host, port = memcached_container.get_host_and_port()
+    """
+
+    def __init__(self, image="memcached:1", port_to_expose=11211, **kwargs):
+        super().__init__(image, **kwargs)
+        self.port_to_expose = port_to_expose
+        self.with_exposed_ports(port_to_expose)
+
+    @wait_container_is_ready(MemcachedNotReady)
+    def _connect(self):
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+            host = self.get_container_host_ip()
+            port = int(self.get_exposed_port(self.port_to_expose))
+            s.connect((host, port))
+            s.sendall(b"stats\n\r")
+            data = s.recv(1024)
+            if len(data) == 0:
+                raise MemcachedNotReady("Memcached not ready yet")
+
+    def start(self):
+        super().start()
+        self._connect()
+        return self
+
+    def get_host_and_port(self):
+        return self.get_container_host_ip(), int(self.get_exposed_port(self.port_to_expose))

modules/memcached/tests/test_memcached.py

@@ -0,0 +1,28 @@
+import socket
+
+from testcontainers.memcached import MemcachedContainer
+
+import pytest
+
+
+def test_memcached_host_and_exposed_port():
+    with MemcachedContainer("memcached:1.6-alpine") as memcached:
+        host, port = memcached.get_host_and_port()
+        assert host == "localhost"
+        assert port != 11211
+
+
+@pytest.mark.parametrize("image", ["memcached:1.6-bookworm", "memcached:1.6-alpine"])
+def test_memcached_can_connect_and_retrieve_data(image):
+    with MemcachedContainer(image) as memcached:
+        host, port = memcached.get_host_and_port()
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+            s.connect((host, port))
+            s.sendall(b"stats\n\r")
+            data = s.recv(1024)
+            assert len(data) > 0, "We should have received some data from memcached"
+
+        pid_stat, uptime_stat, *_ = data.decode().split("\r\n")
+
+        assert pid_stat.startswith("STAT pid")
+        assert uptime_stat.startswith("STAT uptime")

poetry.lock

@@ -40,6 +40,7 @@ packages = [
     { include = "testcontainers", from = "modules/kafka" },
     { include = "testcontainers", from = "modules/keycloak" },
     { include = "testcontainers", from = "modules/localstack" },
+    { include = "testcontainers", from = "modules/memcached" },
     { include = "testcontainers", from = "modules/minio" },
     { include = "testcontainers", from = "modules/mongodb" },
     { include = "testcontainers", from = "modules/mssql" },
@@ -111,6 +112,7 @@ k3s = ["kubernetes", "pyyaml"]
 kafka = []
 keycloak = ["python-keycloak"]
 localstack = ["boto3"]
+memcached = []
 minio = ["minio"]
 mongodb = ["pymongo"]
 mssql = ["sqlalchemy", "pymssql"]