NO-JIRA: chore(tests/containers): improve docker socket detection, reducing the need for TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE

Author: jiridanek

tests/containers/conftest.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING
+import os
+from typing import Iterable, TYPE_CHECKING
 
 import testcontainers.core.config
 import testcontainers.core.container
@@ -11,6 +12,9 @@
 if TYPE_CHECKING:
     from pytest import ExitCode, Session, Parser, Metafunc
 
+SECURITY_OPTION_ROOTLESS = "name=rootless"
+TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE = "TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE"
+
 SHUTDOWN_RYUK = False
 
 # NOTE: Configure Testcontainers through `testcontainers.core.config` and not through env variables.
@@ -26,11 +30,13 @@
 testcontainers.core.config.testcontainers_config.ryuk_privileged = True
 
 
+# https://docs.pytest.org/en/latest/reference/reference.html#pytest.hookspec.pytest_addoption
 def pytest_addoption(parser: Parser) -> None:
     parser.addoption("--image", action="append", default=[],
                      help="Image to use, can be specified multiple times")
 
 
+# https://docs.pytest.org/en/latest/reference/reference.html#pytest.hookspec.pytest_generate_tests
 def pytest_generate_tests(metafunc: Metafunc) -> None:
     if image.__name__ in metafunc.fixturenames:
         metafunc.parametrize(image.__name__, metafunc.config.getoption("--image"))
@@ -43,17 +49,42 @@ def image(request):
     yield request.param
 
 
+# https://docs.pytest.org/en/latest/reference/reference.html#pytest.hookspec.pytest_sessionstart
 def pytest_sessionstart(session: Session) -> None:
     # first preflight check: ping the Docker API
     client = testcontainers.core.docker_client.DockerClient()
     assert client.client.ping(), "Failed to connect to Docker"
 
+    # determine the local socket path
+    # NOTE: this will not work for remote docker, but we will cross the bridge when we come to it
+    socket_path = the_one(adapter.socket_path for adapter in client.client.api.adapters.values())
+
+    # set that socket path for ryuk's use, unless user overrode that
+    if TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE not in os.environ:
+        testcontainers.core.config.testcontainers_config.ryuk_docker_socket = socket_path
+
     # second preflight check: start the Reaper container
-    assert testcontainers.core.container.Reaper.get_instance() is not None, "Failed to start Reaper container"
+    if not testcontainers.core.config.testcontainers_config.ryuk_disabled:
+        assert testcontainers.core.container.Reaper.get_instance() is not None, "Failed to start Reaper container"
 
 
 # https://docs.pytest.org/en/latest/reference/reference.html#pytest.hookspec.pytest_sessionfinish
 def pytest_sessionfinish(session: Session, exitstatus: int | ExitCode) -> None:
     # resolves a shutdown resource leak warning that would be otherwise reported
     if SHUTDOWN_RYUK:
         testcontainers.core.container.Reaper.delete_instance()
+
+
+# https://docs.python.org/3/library/functions.html#iter
+def the_one[T](iterable: Iterable[T]) -> T:
+    """Checks that there is exactly one element in the iterable, and returns it."""
+    it = iter(iterable)
+    try:
+        v = next(it)
+    except StopIteration:
+        raise ValueError("No elements in iterable")
+    try:
+        next(it)
+    except StopIteration:
+        return v
+    raise ValueError("More than one element in iterable")