Add support for ulimit in addon config (#6206)

* Add support for ulimit in addon config

Similar to docker-compose, this adds support for setting ulimits
for addons via the addon config. This is useful e.g. for InfluxDB
which on its own does not support setting higher open file descriptor
limits, but recommends increasing limits on the host.

* Make soft and hard limit mandatory if ulimit is a dict

tests/docker/test_addon.py

@@ -503,3 +503,93 @@ async def test_addon_new_device_no_haos(
     await install_addon_ssh.stop()
     assert coresys.resolution.issues == []
     assert coresys.resolution.suggestions == []
+
+
+async def test_ulimits_integration(
+    coresys: CoreSys,
+    install_addon_ssh: Addon,
+):
+    """Test ulimits integration with Docker addon."""
+    docker_addon = DockerAddon(coresys, install_addon_ssh)
+
+    # Test default case (no ulimits, no realtime)
+    assert docker_addon.ulimits is None
+
+    # Test with realtime enabled (should have built-in ulimits)
+    install_addon_ssh.data["realtime"] = True
+    ulimits = docker_addon.ulimits
+    assert ulimits is not None
+    assert len(ulimits) == 2
+    # Check for rtprio limit
+    rtprio_limit = next((u for u in ulimits if u.name == "rtprio"), None)
+    assert rtprio_limit is not None
+    assert rtprio_limit.soft == 90
+    assert rtprio_limit.hard == 99
+    # Check for memlock limit
+    memlock_limit = next((u for u in ulimits if u.name == "memlock"), None)
+    assert memlock_limit is not None
+    assert memlock_limit.soft == 128 * 1024 * 1024
+    assert memlock_limit.hard == 128 * 1024 * 1024
+
+    # Test with configurable ulimits (simple format)
+    install_addon_ssh.data["realtime"] = False
+    install_addon_ssh.data["ulimits"] = {"nofile": 65535, "nproc": 32768}
+    ulimits = docker_addon.ulimits
+    assert ulimits is not None
+    assert len(ulimits) == 2
+
+    nofile_limit = next((u for u in ulimits if u.name == "nofile"), None)
+    assert nofile_limit is not None
+    assert nofile_limit.soft == 65535
+    assert nofile_limit.hard == 65535
+
+    nproc_limit = next((u for u in ulimits if u.name == "nproc"), None)
+    assert nproc_limit is not None
+    assert nproc_limit.soft == 32768
+    assert nproc_limit.hard == 32768
+
+    # Test with configurable ulimits (detailed format)
+    install_addon_ssh.data["ulimits"] = {
+        "nofile": {"soft": 20000, "hard": 40000},
+        "memlock": {"soft": 67108864, "hard": 134217728},
+    }
+    ulimits = docker_addon.ulimits
+    assert ulimits is not None
+    assert len(ulimits) == 2
+
+    nofile_limit = next((u for u in ulimits if u.name == "nofile"), None)
+    assert nofile_limit is not None
+    assert nofile_limit.soft == 20000
+    assert nofile_limit.hard == 40000
+
+    memlock_limit = next((u for u in ulimits if u.name == "memlock"), None)
+    assert memlock_limit is not None
+    assert memlock_limit.soft == 67108864
+    assert memlock_limit.hard == 134217728
+
+    # Test mixed format and realtime (realtime + custom ulimits)
+    install_addon_ssh.data["realtime"] = True
+    install_addon_ssh.data["ulimits"] = {
+        "nofile": 65535,
+        "core": {"soft": 0, "hard": 0},  # Disable core dumps
+    }
+    ulimits = docker_addon.ulimits
+    assert ulimits is not None
+    assert (
+        len(ulimits) == 4
+    )  # rtprio, memlock (from realtime) + nofile, core (from config)
+
+    # Check realtime limits still present
+    rtprio_limit = next((u for u in ulimits if u.name == "rtprio"), None)
+    assert rtprio_limit is not None
+
+    # Check custom limits added
+    nofile_limit = next((u for u in ulimits if u.name == "nofile"), None)
+    assert nofile_limit is not None
+    assert nofile_limit.soft == 65535
+    assert nofile_limit.hard == 65535
+
+    core_limit = next((u for u in ulimits if u.name == "core"), None)
+    assert core_limit is not None
+    assert core_limit.soft == 0
+    assert core_limit.hard == 0