docker_swarm_service: Add placement_preferences option (#51082)

* Add placement_preferences option

* Add changelog fragment

* Python 2.6 compat

Python 2.6 compat

* Cleaner check

* Better description

* Don’t compare placement_preferences if None

* Add placement_preferences example

changelogs/fragments/51082-docker_swarm_service-placement-preferences-option.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - "docker_swarm_service - Added support for ``placement_preferences`` parameter."

lib/ansible/modules/cloud/docker/docker_swarm_service.py

@@ -47,6 +47,13 @@ options:
     description:
     - List of the service constraints.
     - Maps docker service --constraint option.
+  placement_preferences:
+    required: false
+    type: list
+    description:
+    - List of the placement preferences as key value pairs.
+    - Maps docker service C(--placement-pref) option.
+    version_added: 2.8
   hostname:
     required: false
     default: ""
@@ -495,6 +502,12 @@ EXAMPLES = '''
     docker_swarm_service:
         name: myservice
         state: absent
+-   name: set placement preferences
+    docker_swarm_service:
+        name: myservice
+        image: alpine:edge
+        placement_preferences:
+          - spread: "node.labels.mylabel"
 '''
 
 import time
@@ -518,7 +531,6 @@ except Exception:
 class DockerService(DockerBaseClass):
     def __init__(self):
         super(DockerService, self).__init__()
-        self.constraints = []
         self.image = ""
         self.args = []
         self.endpoint_mode = "vip"
@@ -545,6 +557,8 @@ class DockerService(DockerBaseClass):
         self.constraints = []
         self.networks = []
         self.publish = []
+        self.constraints = []
+        self.placement_preferences = None
         self.replicas = -1
         self.service_id = False
         self.service_version = False
@@ -577,6 +591,7 @@ class DockerService(DockerBaseClass):
             'log_driver_options': self.log_driver_options,
             'publish': self.publish,
             'constraints': self.constraints,
+            'placement_preferences': self.placement_preferences,
             'labels': self.labels,
             'container_labels': self.container_labels,
             'mode': self.mode,
@@ -601,6 +616,7 @@ class DockerService(DockerBaseClass):
     def from_ansible_params(ap, old_service):
         s = DockerService()
         s.constraints = ap['constraints']
+        s.placement_preferences = ap['placement_preferences']
         s.image = ap['image']
         s.args = ap['args']
         s.endpoint_mode = ap['endpoint_mode']
@@ -726,6 +742,8 @@ class DockerService(DockerBaseClass):
             differences.add('args', parameter=self.args, active=os.args)
         if self.constraints != os.constraints:
             differences.add('constraints', parameter=self.constraints, active=os.constraints)
+        if self.placement_preferences is not None and self.placement_preferences != os.placement_preferences:
+            differences.add('placement_preferences', parameter=self.placement_preferences, active=os.placement_preferences)
         if self.labels != os.labels:
             differences.add('labels', parameter=self.labels, active=os.labels)
         if self.limit_cpu != os.limit_cpu:
@@ -864,7 +882,14 @@ class DockerService(DockerBaseClass):
 
         log_driver = types.DriverConfig(name=self.log_driver, options=self.log_driver_options)
 
-        placement = types.Placement(constraints=self.constraints)
+        placement = types.Placement(
+            constraints=self.constraints,
+            preferences=[
+                {key.title(): {"SpreadDescriptor": value}}
+                for preference in self.placement_preferences
+                for key, value in preference.items()
+            ] if self.placement_preferences else None,
+        )
 
         restart_policy = types.RestartPolicy(
             condition=self.restart_policy,
@@ -979,7 +1004,17 @@ class DockerServiceManager():
         ds.hostname = task_template_data['ContainerSpec'].get('Hostname', '')
         ds.tty = task_template_data['ContainerSpec'].get('TTY', False)
         if 'Placement' in task_template_data.keys():
-            ds.constraints = task_template_data['Placement'].get('Constraints', [])
+            placement = task_template_data['Placement']
+            ds.constraints = placement.get('Constraints', [])
+            placement_preferences = []
+            for preference in placement.get('Preferences', []):
+                placement_preferences.append(
+                    dict(
+                        (key.lower(), value["SpreadDescriptor"])
+                        for key, value in preference.items()
+                    )
+                )
+            ds.placement_preferences = placement_preferences or None
 
         restart_policy_data = task_template_data.get('RestartPolicy', None)
         if restart_policy_data:
@@ -1193,6 +1228,7 @@ def main():
             mode=dict(type='str', required=False, choices=('ingress', 'host')),
         )),
         constraints=dict(default=[], type='list'),
+        placement_preferences=dict(default=None, type='list'),
         tty=dict(default=False, type='bool'),
         dns=dict(default=[], type='list'),
         dns_search=dict(default=[], type='list'),

test/integration/targets/docker_swarm_service/tasks/tests/options.yml

@@ -950,6 +950,46 @@
       - networks_2 is not changed
       - networks_3 is changed
 
+####################################################################
+## placement_preferences ###########################################
+####################################################################
+
+- name: placement_preferences
+  docker_swarm_service:
+    name: "{{ service_name }}"
+    image: alpine:3.8
+    placement_preferences:
+      - spread: "node.labels.test"
+  register: placement_preferences_1
+
+- name: placement_preferences (idempotency)
+  docker_swarm_service:
+    name: "{{ service_name }}"
+    image: alpine:3.8
+    placement_preferences:
+      - spread: "node.labels.test"
+  register: placement_preferences_2
+
+- name: placement_preferences (change)
+  docker_swarm_service:
+    name: "{{ service_name }}"
+    image: alpine:3.8
+    placement_preferences:
+      - spread: "node.labels.test2"
+  register: placement_preferences_3
+
+- name: cleanup
+  docker_swarm_service:
+    name: "{{ service_name }}"
+    state: absent
+  diff: no
+
+- assert:
+    that:
+      - placement_preferences_1 is changed
+      - placement_preferences_2 is not changed
+      - placement_preferences_3 is changed
+
 ####################################################################
 ## publish #########################################################
 ####################################################################

test/integration/targets/docker_swarm_service/vars/main.yml

@@ -21,6 +21,7 @@ service_expected_output:
   mode: global
   mounts: []
   networks: []
+  placement_preferences: null
   publish:
     - {mode: null, protocol: tcp, published_port: 60001, target_port: 60001}
     - {mode: null, protocol: udp, published_port: 60001, target_port: 60001}