Scaleway inventory: allows to connect via private IP (#44342)

* scaleway inventory: remove useless duplicate

* scaleway inventory: allows to connect using private ip

ansible_host was hardcoded and it was not possible to connect using
private addresses.
This allows to define multiple host variables, values are templates
which can use hosts details send by API. For example this config file
use private address and defines two variables:

    plugin: scaleway
    hostnames:
      - hostname
    variables:
      ansible_host: private_ip
      state: state
      image: image.name
    regions:
      - ams1

inventory will looks like:

    {
        "_meta": {
            "hostvars": {
                "testhost": {
                    "ansible_host": "10.1.1.1",
                    "arch": "x86_64",
                    "commercial_type": "START1-M",
                    "hostname": "testhost",
                    "id": "af669464-0c74-4c89-8573-9fe763028448",
                    "image": "CentOS 7.4",
                    "organization": "2cc9a115-380d-4ac0-ba4b-8947eee71325",
                    "public_ipv4": "163.172.1.1",
                    "public_ipv6": "2001:bc8::1",
                    "state": "running",
                    "tags": [
                        "testtag"
                    ]
                }
            }
        },
        [...]
    }

lib/ansible/plugins/inventory/scaleway.py

@@ -46,12 +46,20 @@ DOCUMENTATION = '''
                 - public_ipv6
                 - hostname
                 - id
+        variables:
+            description: 'set individual variables: keys are variable names and
+                          values are templates. Any value returned by the
+                          L(Scaleway API, https://developer.scaleway.com/#servers-server-get)
+                          can be used.'
+            type: dict
 '''
 
 EXAMPLES = '''
 # scaleway_inventory.yml file in YAML format
 # Example command line: ansible-inventory --list -i scaleway_inventory.yml
 
+# use hostname as inventory_hostname
+# use the private IP address to connect to the host
 plugin: scaleway
 regions:
   - ams1
@@ -59,13 +67,25 @@ regions:
 tags:
   - foobar
 hostnames:
-  - public_ipv4
+  - hostname
+variables:
+  ansible_host: private_ip
+  state: state
+
+# use hostname as inventory_hostname and public IP address to connect to the host
+plugin: scaleway
+hostnames:
+  - hostname
+regions:
+  - par1
+variables:
+  ansible_host: public_ip.address
 '''
 
 import json
 
 from ansible.errors import AnsibleError
-from ansible.plugins.inventory import BaseInventoryPlugin
+from ansible.plugins.inventory import BaseInventoryPlugin, Constructable
 from ansible.module_utils.scaleway import SCALEWAY_LOCATION
 from ansible.module_utils.urls import open_url
 from ansible.module_utils._text import to_native
@@ -152,7 +172,7 @@ extractors = {
 }
 
 
-class InventoryModule(BaseInventoryPlugin):
+class InventoryModule(BaseInventoryPlugin, Constructable):
     NAME = 'scaleway'
 
     def _fill_host_variables(self, host, server_info):
@@ -163,7 +183,6 @@ class InventoryModule(BaseInventoryPlugin):
             "organization",
             "state",
             "hostname",
-            "state"
         )
         for attribute in targeted_attributes:
             self.inventory.set_variable(host, attribute, server_info[attribute])
@@ -175,7 +194,6 @@ class InventoryModule(BaseInventoryPlugin):
 
         if extract_public_ipv4(server_info=server_info):
             self.inventory.set_variable(host, "public_ipv4", extract_public_ipv4(server_info=server_info))
-            self.inventory.set_variable(host, "ansible_host", extract_public_ipv4(server_info=server_info))
 
         if extract_private_ipv4(server_info=server_info):
             self.inventory.set_variable(host, "private_ipv4", extract_private_ipv4(server_info=server_info))
@@ -233,6 +251,9 @@ class InventoryModule(BaseInventoryPlugin):
                 self.inventory.add_host(group=group, host=hostname)
                 self._fill_host_variables(host=hostname, server_info=host_infos)
 
+                # Composed variables
+                self._set_composite_vars(self.get_option('variables'), host_infos, hostname, strict=False)
+
     def parse(self, inventory, loader, path, cache=True):
         super(InventoryModule, self).parse(inventory, loader, path)
         self._read_config_data(path=path)