feat(filters): add active_docker_container_count filter and use it for fair resource splits

Compute per-container CPU/RAM shares based on active services (web-/svc-*, enabled=true or undefined). Cast host facts to numbers, add safe min=1, and output compose-ready values. Include robust unit test.

Also: include resource.yml.j2 in base template and minor formatting tidy-up.

https://chatgpt.com/share/68d2d96c-9bf4-800f-bbec-d4f2c0051c06

filter_plugins/active_docker.py

@@ -0,0 +1,79 @@
+# -*- coding: utf-8 -*-
+"""
+Ansible filter to count active docker services for current host.
+
+Active means:
+- application key is in group_names
+- application key matches prefix regex (default: ^(web-|svc-).* )
+- under applications[app]['docker']['services'] each service is counted if:
+  - 'enabled' is True, OR
+  - 'enabled' is missing/undefined  (treated as active)
+
+Returns an integer. If ensure_min_one=True, returns at least 1.
+"""
+
+import re
+from typing import Any, Dict, Mapping, Iterable
+
+
+def _is_mapping(x: Any) -> bool:
+    # be liberal: Mapping covers dict-like; fallback to dict check
+    try:
+        return isinstance(x, Mapping)
+    except Exception:
+        return isinstance(x, dict)
+
+
+def active_docker_container_count(applications: Mapping[str, Any],
+                                  group_names: Iterable[str],
+                                  prefix_regex: str = r'^(web-|svc-).*',
+                                  ensure_min_one: bool = False) -> int:
+    if not _is_mapping(applications):
+        return 1 if ensure_min_one else 0
+
+    group_set = set(group_names or [])
+    try:
+        pattern = re.compile(prefix_regex)
+    except re.error:
+        pattern = re.compile(r'^(web-|svc-).*')  # fallback
+
+    count = 0
+
+    for app_key, app_val in applications.items():
+        # host selection + name prefix
+        if app_key not in group_set:
+            continue
+        if not pattern.match(str(app_key)):
+            continue
+
+        docker = app_val.get('docker') if _is_mapping(app_val) else None
+        services = docker.get('services') if _is_mapping(docker) else None
+        if not _is_mapping(services):
+            # sometimes roles define a single service name string; ignore
+            continue
+
+        for _svc_name, svc_cfg in services.items():
+            if not _is_mapping(svc_cfg):
+                # allow shorthand like: service: {} or image string -> counts as enabled
+                count += 1
+                continue
+            enabled = svc_cfg.get('enabled', True)
+            if isinstance(enabled, bool):
+                if enabled:
+                    count += 1
+            else:
+                # non-bool enabled -> treat "truthy" as enabled
+                if bool(enabled):
+                    count += 1
+
+    if ensure_min_one and count < 1:
+        return 1
+    return count
+
+
+class FilterModule(object):
+    def filters(self):
+        return {
+            # usage: {{ applications | active_docker_container_count(group_names) }}
+            'active_docker_container_count': active_docker_container_count,
+        }

group_vars/all/18_resource.yml

@@ -0,0 +1,41 @@
+# Host resources
+RESOURCE_HOST_CPUS:  "{{ ansible_processor_vcpus | int }}"
+RESOURCE_HOST_MEM:   "{{ (ansible_memtotal_mb | int) // 1024 }}"
+
+# Reserve for OS
+RESOURCE_HOST_RESERVE_CPU: 2
+RESOURCE_HOST_RESERVE_MEM: 4
+
+# Available for apps
+RESOURCE_AVAIL_CPUS: "{{ (RESOURCE_HOST_CPUS | int) - (RESOURCE_HOST_RESERVE_CPU | int) }}"
+RESOURCE_AVAIL_MEM:  "{{ (RESOURCE_HOST_MEM  | int) - (RESOURCE_HOST_RESERVE_MEM | int) }}"
+
+# Count active docker services (only roles starting with web- or svc-; service counts if enabled==true OR enabled is undefined)
+RESOURCE_ACTIVE_DOCKER_CONTAINER_COUNT: >-
+  {{
+    applications
+    | active_docker_container_count(group_names, '^(web-|svc-).*', ensure_min_one=True)
+  }}
+
+# Per-container fair share (numbers!), later we append 'g' only for the string fields in compose
+RESOURCE_CPUS_NUM: >-
+  {{
+    ((RESOURCE_AVAIL_CPUS | float) / (RESOURCE_ACTIVE_DOCKER_CONTAINER_COUNT | float))
+    | round(2)
+  }}
+RESOURCE_MEM_RESERVATION_NUM: >-
+  {{
+    (((RESOURCE_AVAIL_MEM  | float) / (RESOURCE_ACTIVE_DOCKER_CONTAINER_COUNT | float)) * 0.7)
+    | round(1)
+  }}
+RESOURCE_MEM_LIMIT_NUM: >-
+  {{
+    (((RESOURCE_AVAIL_MEM  | float) / (RESOURCE_ACTIVE_DOCKER_CONTAINER_COUNT | float)) * 1.0)
+    | round(1)
+  }}
+
+# Final strings with units for compose defaults (keep numbers above for math elsewhere if needed)
+RESOURCE_CPUS:            "{{ RESOURCE_CPUS_NUM }}"
+RESOURCE_MEM_RESERVATION: "{{ RESOURCE_MEM_RESERVATION_NUM }}g"
+RESOURCE_MEM_LIMIT:       "{{ RESOURCE_MEM_LIMIT_NUM }}g"
+RESOURCE_PIDS_LIMIT: 512

roles/docker-container/templates/base.yml.j2

@@ -7,5 +7,5 @@
 {% endif %}
     logging:
       driver: journald
-
+    {{ lookup('template', 'roles/docker-container/templates/resource.yml.j2') | indent(4) }}
 {{ "\n" }}

roles/docker-container/templates/resource.yml.j2

@@ -0,0 +1,4 @@
+cpus:               {{ applications | get_app_conf( application_id,  [ 'docker', 'services', service_name|default(application_id | get_entity_name ), 'cpus'            ] |join('.'), False, RESOURCE_CPUS) }}
+mem_reservation:    {{ applications | get_app_conf( application_id,  [ 'docker', 'services', service_name|default(application_id | get_entity_name ), 'mem_reservation' ] |join('.'), False, RESOURCE_MEM_RESERVATION) }}
+mem_limit:          {{ applications | get_app_conf( application_id,  [ 'docker', 'services', service_name|default(application_id | get_entity_name ), 'mem_limit'       ] |join('.'), False, RESOURCE_MEM_LIMIT) }}
+pids_limit:         {{ applications | get_app_conf( application_id,  [ 'docker', 'services', service_name|default(application_id | get_entity_name ), 'pids_limit'      ] |join('.'), False, RESOURCE_PIDS_LIMIT) }}

tests/unit/filter_plugins/test_active_docker.py

@@ -0,0 +1,158 @@
+# tests/unit/filter_plugins/test_active_docker.py
+import os
+import sys
+import unittest
+from pathlib import Path
+
+# Ensure repository root is on sys.path so "filter_plugins" can be imported
+ROOT = Path(__file__).resolve().parents[3]  # .../tests/unit/filter_plugins -> repo root
+sys.path.insert(0, str(ROOT))
+
+from filter_plugins.active_docker import (
+    active_docker_container_count,
+    FilterModule,
+)
+
+
+class TestActiveDockerFilter(unittest.TestCase):
+    def setUp(self):
+        # default group_names simulating current host membership
+        self.group_names = [
+            "web-app-jira",
+            "web-app-confluence",
+            "svc-db-postgres",
+            "svc-ai-ollama",
+            "web-svc-cdn",
+            "unrelated-group",
+        ]
+
+        # a representative applications structure
+        self.apps = {
+            # counted (prefix web-/svc- AND in group_names)
+            "web-app-jira": {
+                "docker": {
+                    "services": {
+                        "jira": {"enabled": True},
+                        "proxy": {},  # enabled undefined -> counts
+                        "debug": {"enabled": False},  # should NOT count
+                    }
+                }
+            },
+            "web-app-confluence": {
+                "docker": {
+                    "services": {
+                        "confluence": {"enabled": True},
+                    }
+                }
+            },
+            "svc-db-postgres": {
+                "docker": {
+                    "services": {
+                        "postgres": {"enabled": True},
+                        "backup": {"enabled": False},  # no
+                    }
+                }
+            },
+            "svc-ai-ollama": {
+                "docker": {
+                    "services": {
+                        # non-dict service cfg (string) -> should count as "enabled"
+                        "ollama": "ghcr.io/ollama/ollama:latest",
+                    }
+                }
+            },
+            "web-svc-cdn": {
+                "docker": {
+                    "services": {
+                        # weird truthy value -> treated as enabled
+                        "cdn": {"enabled": "yes"},
+                    }
+                }
+            },
+
+            # NOT counted: wrong prefix
+            "db-core-mariadb": {
+                "docker": {"services": {"mariadb": {"enabled": True}}}
+            },
+            # NOT counted: not in group_names
+            "web-app-gitlab": {
+                "docker": {"services": {"gitlab": {"enabled": True}}}
+            },
+            # NOT counted: missing docker/services
+            "web-app-empty": {},
+        }
+
+    def test_basic_count(self):
+        # Expected counted services:
+        # web-app-jira: jira(True) + proxy(undefined) = 2
+        # web-app-confluence: confluence(True) = 1
+        # svc-db-postgres: postgres(True) = 1
+        # svc-ai-ollama: ollama(string) = 1
+        # web-svc-cdn: cdn("yes") -> truthy = 1
+        # Total = 6
+        cnt = active_docker_container_count(self.apps, self.group_names)
+        self.assertEqual(cnt, 6)
+
+    def test_filter_module_registration(self):
+        fm = FilterModule().filters()
+        self.assertIn("active_docker_container_count", fm)
+        cnt = fm["active_docker_container_count"](self.apps, self.group_names)
+        self.assertEqual(cnt, 6)
+
+    def test_prefix_regex_override(self):
+        # Only count svc-* prefixed apps in group_names
+        cnt = active_docker_container_count(
+            self.apps, self.group_names, prefix_regex=r"^svc-.*"
+        )
+        # svc-db-postgres (1) + svc-ai-ollama (1) = 2
+        self.assertEqual(cnt, 2)
+
+    def test_not_in_group_names_excluded(self):
+        # Add a matching app but omit from group_names → should not count
+        apps = dict(self.apps)
+        apps["web-app-pixelfed"] = {"docker": {"services": {"pix": {"enabled": True}}}}
+        cnt = active_docker_container_count(apps, self.group_names)
+        # stays 6
+        self.assertEqual(cnt, 6)
+
+    def test_missing_services_and_non_mapping(self):
+        # If applications is not a mapping, returns 0/1 based on ensure_min_one
+        self.assertEqual(active_docker_container_count(None, self.group_names), 0)
+        self.assertEqual(
+            active_docker_container_count(None, self.group_names, ensure_min_one=True),
+            1,
+        )
+
+        # App with no docker/services should be ignored (already in fixture)
+        cnt = active_docker_container_count(self.apps, self.group_names)
+        self.assertEqual(cnt, 6)
+
+    def test_enabled_false_excluded(self):
+        # Ensure explicit false is excluded
+        apps = dict(self.apps)
+        apps["web-app-jira"]["docker"]["services"]["only_false"] = {"enabled": False}
+        cnt = active_docker_container_count(apps, self.group_names)
+        self.assertEqual(cnt, 6)  # unchanged
+
+    def test_enabled_truthy_string_included(self):
+        # Already covered by web-svc-cdn ("yes"), but verify explicitly
+        apps = dict(self.apps)
+        apps["web-app-confluence"]["docker"]["services"]["extra"] = {"enabled": "true"}
+        cnt = active_docker_container_count(apps, self.group_names)
+        self.assertEqual(cnt, 7)
+
+    def test_ensure_min_one(self):
+        # Construct inputs that produce zero
+        apps = {
+            "web-app-foo": {"docker": {"services": {"s": {"enabled": False}}}},
+        }
+        cnt0 = active_docker_container_count(apps, ["web-app-foo"])
+        cnt1 = active_docker_container_count(
+            apps, ["web-app-foo"], ensure_min_one=True
+        )
+        self.assertEqual(cnt0, 0)
+        self.assertEqual(cnt1, 1)
+
+
+if __name__ == "__main__":
+    unittest.main()