Fix gunicorn "Control server error" on kubernetes

CHANGES/7574.bugfix

@@ -0,0 +1,4 @@
+Added option to `pulpcore-content` to configure the gunicorn control socket path.
+The default path could cause permission errors on certain deployments setups.
+
+This feature was added in gunicorn>=25.1 and is ignored for lower version.

pulpcore/app/entrypoint.py

@@ -146,7 +146,7 @@ def load(self):
 
 
 @click.option(
-    "--bind", "-b", default=[f"{ '[::]' if has_ipv6() else '0.0.0.0' }:24817"], multiple=True
+    "--bind", "-b", default=[f"{'[::]' if has_ipv6() else '0.0.0.0'}:24817"], multiple=True
 )
 @click.option("--workers", "-w", type=int)
 # @click.option("--threads", "-w", type=int)  # We don't use a threaded worker...

pulpcore/content/entrypoint.py

@@ -1,6 +1,7 @@
 import sys
 
 import click
+from importlib.metadata import version as pkg_version
 from pulpcore.app.netutil import has_ipv6
 from pulpcore.app.pulpcore_gunicorn_application import PulpcoreGunicornApplication
 from django.conf import settings
@@ -22,8 +23,23 @@ def load(self):
         return pulpcore.content.server
 
 
+def _handle_control_interface_feature(options):
+    """Drop control_socket from options if gunicorn<25.1, which introduced the feature."""
+    # TODO: remove this function when gunicorn lowerbound>=25.1
+    if options.get("control_socket") is None:
+        return
+
+    gunicorn_version = tuple(int(x) for x in pkg_version("gunicorn").split(".")[:2])
+    if gunicorn_version < (25, 1):
+        sys.stderr.write(
+            "Warning: --control-socket requires gunicorn>=25.1, ignoring "
+            f"(installed: {'.'.join(str(x) for x in gunicorn_version)}).\n"
+        )
+        options["control_socket"] = None
+
+
 @click.option(
-    "--bind", "-b", default=[f"{ '[::]' if has_ipv6() else '0.0.0.0' }:24816"], multiple=True
+    "--bind", "-b", default=[f"{'[::]' if has_ipv6() else '0.0.0.0'}:24816"], multiple=True
 )
 @click.option("--workers", "-w", type=int)
 # @click.option("--threads", "-w", type=int)  # We don't use a threaded worker...
@@ -50,6 +66,11 @@ def load(self):
 @click.option("--chdir")
 @click.option("--user", "-u")
 @click.option("--group", "-g")
+@click.option(
+    "--control-socket",
+    "control_socket",
+    help="Path to the gunicorn control socket (requires gunicorn>=25.1).",
+)
 @click.option(
     "--name-template",
     type=str,
@@ -61,5 +82,6 @@ def main(bind, name_template, **options):
     if name_template:
         settings.set("WORKER_NAME_TEMPLATE", name_template)
     options["bind"] = list(bind)
+    _handle_control_interface_feature(options)
     sys.argv = sys.argv[:1]
     PulpcoreContentApplication(options).run()