Add property extra_entrypoint_args to support appending arguments to …

…the container launch command

This fixes #168

CHANGELOG.rst

@@ -14,6 +14,9 @@ Breaking changes:
 
 Improvements and new features:
 
+- Add property
+  :py:attr:`~pytest_container.container.ContainerBase.extra_entrypoint_args` to
+  support appending arguments to the container launch command
 
 Documentation:
 

pytest_container/container.py

@@ -447,10 +447,21 @@ class ContainerBase:
     custom_entry_point: Optional[str] = None
 
     #: List of additional flags that will be inserted after
-    #: `docker/podman run -d`. The list must be properly escaped, e.g. as
-    #: created by `shlex.split`
+    #: `docker/podman run -d` and before the image name (i.e. these arguments
+    #: are not passed to the entrypoint or ``CMD``). The list must be properly
+    #: escaped, e.g. as created by ``shlex.split``.
     extra_launch_args: List[str] = field(default_factory=list)
 
+    #: List of additional arguments that are passed to the ``CMD`` or
+    #: entrypoint. These arguments are inserted after the :command:`docker/podman
+    #: run -d $image` on launching the image.
+    #: The list must be properly escaped, e.g. by passing the string through
+    #: ``shlex.split``.
+    #: The arguments must not cause the container to exit early. It must remain
+    #: active in the background, otherwise this library will not function
+    #: properly.
+    extra_entrypoint_args: List[str] = field(default_factory=list)
+
     #: Time for the container to become healthy (the timeout is ignored
     #: when the container image defines no ``HEALTHCHECK`` or when the timeout
     #: is below zero).
@@ -571,6 +582,8 @@ def get_launch_cmd(
         else:  # pragma: no cover
             assert False, "This branch must be unreachable"  # pragma: no cover
 
+        cmd.extend(self.extra_entrypoint_args)
+
         return cmd
 
     @property

source/usage.rst

@@ -394,8 +394,8 @@ follows:
    :command:`podman`.
 
 
-Entrypoint and stop signal handling
------------------------------------
+Entrypoint, launch command and stop signal handling
+---------------------------------------------------
 
 ``pytest_container`` will by default (when
 :py:attr:`~pytest_container.container.ContainerBase.entry_point` is set to
@@ -419,6 +419,14 @@ image without specifying one
 (:py:attr:`~pytest_container.container.EntrypointSelection.IMAGE`).
 
 
+The container under test is launched by default with no further
+arguments. Additional arguments can be passed to the entrypoint via the
+parameter
+:py:attr:`~pytest_container.container.ContainerBase.extra_entrypoint_args`. The
+list of arguments/parameters is appended to the container launch command line
+after the container image.
+
+
 Changing the container entrypoint can have a catch with respect to the
 ``STOPSIGNAL`` defined by a container image. Container images that have
 non-shell entry points sometimes use a different signal for stopping the main

tests/test_launcher.py

@@ -44,6 +44,16 @@
     custom_entry_point="/bin/sh",
 )
 
+PYTHON_LEAP = DerivedContainer(
+    base=LEAP,
+    containerfile="""
+RUN set -euxo pipefail; zypper -n ref; zypper -n in python3 curl;
+
+ENTRYPOINT ["/usr/bin/python3"]
+CMD ["-m", "http.server"]
+""",
+)
+
 
 def _test_func(con: Any) -> None:
     sleep(5)
@@ -268,3 +278,28 @@ def try_launch():
     assert not Path(
         tempfile.gettempdir(), container_with_wrong_url.filelock_filename
     ).exists()
+
+
+@pytest.mark.parametrize(
+    "container,port_num",
+    [
+        (
+            DerivedContainer(
+                base=PYTHON_LEAP,
+                extra_entrypoint_args=[
+                    "-m",
+                    "http.server",
+                    "8080"
+                ],
+            ),
+            8080,
+        ),
+        (PYTHON_LEAP, 8000),
+    ],
+    indirect=["container"],
+)
+def test_extra_command_args(container: ContainerData, port_num: int) -> None:
+    print(id(container.container))
+    assert container.connection.check_output(
+        f"curl http://localhost:{port_num}"
+    )