{"id":462,"date":"2022-06-19T19:36:29","date_gmt":"2022-06-19T19:36:29","guid":{"rendered":"https:\/\/www.adriatic-staging.mattbedford.work\/?p=462"},"modified":"2022-07-28T11:31:35","modified_gmt":"2022-07-28T11:31:35","slug":"custom-ansible-modules-with-python-class","status":"publish","type":"post","link":"https:\/\/www.adriaticnetworks.com\/de\/custom-ansible-modules-with-python-class\/","title":{"rendered":"Ma\u00dfgeschneiderte Ansible-Module mit Python Class"},"content":{"rendered":"

In jedem ernsten Netzwerkautomatisierungsprojekt kommen wir irgendwann zum Punkt, wo weder eingebaute Ansible-Module noch Ansible Galaxy Module ausreichend sind, um ma\u00dfgeschneiderte Anforderungen implementieren zu k\u00f6nnen. Deswegen finden wir die L\u00f6sung in der Erstellung von unseren eigenen, ma\u00dfgeschneiderten Ansible-Modulen. Dank dem flexiblen Design von Ansible kann man das sehr einfach mithilfe von Python-Programmierung schaffen. Ein funktionaler Python-Code sollte f\u00fcr viele Ansible-Module v\u00f6llig ausreichend sein. In einigen F\u00e4llen, vor allem im Zusammenhang mit der Netzwerkautomatisierung, wird Verst\u00e4ndnis und Aufrechterhaltung von und Bewegung durch den funktionalen Python-Code gelegentlich zu umst\u00e4ndlich. In diesem Tutorium zeigen wir, wie man die gleiche Modulf\u00e4higkeit mit funktionalem Stil und Class-Style (OOP) kodieren schaffen kann.<\/p>\n\n\n\n

Angenommen, unsere Aufgabe ist es, ein unkompliziertes Modul zu schaffen, der Junos CLI aus einem vorgegebenen Datenmodel erzeugt. Wir konzentrieren uns ausschlie\u00dflich auf die Adresse und Adressengruppen. F\u00fcr den Adressennamen ADDRESS_SRC1<\/strong> und Adressensubnetz 10.10.10.0\/24<\/strong> und Adressensubnetz 10.10.10.0\/24 muss man den folgenden Befehlssatz generieren: set security address-book global address ADDRESS_SRC1 10.10.10.0\/24<\/code><\/strong>. Provided that this address object should be associated with address group named AG_SRC<\/strong> verbunden sein m\u00fcsste, wird das Modul folgende Konfigurationszeile generieren: set security address-book global address-set AG_SRC address ADDRESS_SRC1<\/code><\/strong>.<\/p>\n\n\n\n

Unser Datenmodul soll folgenderma\u00dfen aussehen:<\/p>\n\n\n\n

main.yml<\/strong> <\/p>\n\n\n\n

- hosts: localhost\n  gather_facts: no\n\n  vars:\n    addresses_list_of_dicts:\n      - name: ADDRESS_SRC1\n        subnet: 10.10.10.0\/24\n      - name: ADDRESS_SRC2\n        subnet: 11.11.11.0\/24\n      - name: ADDRESS_DST1\n        subnet: 200.200.200.0\/24\n      - name: ADDRESS_DST2\n        subnet: 222.222.222.0\/24\n    address_groups_list_of_dicts:\n      - name: AG_SRC\n        addresses: \n          - ADDRESS_SRC1\n          - ADDRESS_SRC2\n      - name: AG_DST\n        addresses: \n          - ADDRESS_DST1\n          - ADDRESS_DST2\n\n<\/code><\/pre>\n\n\n\n
Jedes Item unter <strong>addresses_list_of_dicts<\/strong><\/code> m\u00fcsste zu einem neuen Adressenobjekt werden. Ebenso m\u00fcsste f\u00fcr jedes Item unter <strong>address_groups_list_of_dicts<\/strong> <\/code>ein Adressengruppenobjekt erstellt werden.<\/p>\n\n\n\n
Wir m\u00f6chten unser ma\u00dfgeschneidertes Ansible-Modul create_junos_config1<\/code><\/strong> nennen, was bedeutet, dass die Datei create_junos_config1.py<\/code><\/strong> im Ordner <strong>library<\/strong> <\/code>sein muss. Wir tragen die Input-Daten folgenderma\u00dfen ein:<\/p>\n\n\n\n
main.yml<\/strong>   <\/p>\n\n\n\n
- hosts: localhost\n  gather_facts: no\n\n  vars:\n    addresses_list_of_dicts:\n      - name: ADDRESS_SRC1\n        subnet: 10.10.10.0\/24\n      - name: ADDRESS_SRC2\n        subnet: 11.11.11.0\/24\n      - name: ADDRESS_DST1\n        subnet: 200.200.200.0\/24\n      - name: ADDRESS_DST2\n        subnet: 222.222.222.0\/24\n    address_groups_list_of_dicts:\n      - name: AG_SRC\n        addresses: \n          - ADDRESS_SRC1\n          - ADDRESS_SRC2\n      - name: AG_DST\n        addresses: \n          - ADDRESS_DST1\n          - ADDRESS_DST2\n\n  tasks:\n    - name: Generate Junos CLI commands\n      create_junos_config1:\n        addresses: "{{ addresses_list_of_dicts }}"\n        address_groups: "{{ address_groups_list_of_dicts }}"\n      register: junos_config1\n\n    - name: Print Junos CLI commands\n      debug:\n        msg: "{{ junos_config1 }}"\n<\/code><\/pre>\n\n\n\n
Hier ist der Python-Code dieses Moduls:<\/p>\n\n\n\n
create_junos_config1.py<\/strong>   <\/p>\n\n\n\n
#!\/usr\/bin\/python\n\nfrom ansible.module_utils.basic import AnsibleModule\n\ndef main():\n    # Define input params\n    inputparams = {\n        "addresses": {"required": True, "type": "list"},\n        "address_groups": {"required": True, "type": "list"},\n    }\n\n    # Read input params\n    module = AnsibleModule(argument_spec=inputparams)\n\n    addresses = module.params["addresses"]\n    address_groups = module.params["address_groups"]\n\n    # Outputs\n    config = []\n\n    # Business logic\n    for addr in addresses:\n        cmd = (\n            f"set security address-book global address {addr['name']}"\n            f" {addr['subnet']}"\n        )\n        config.append(cmd)\n\n    for ag in address_groups:\n        for addr in ag["addresses"]:\n            cmd = (\n                f"set security address-book global address-set {ag['name']}"\n                f" address {addr}"\n            )\n            config.append(cmd)\n\n    # Exit module, back to playbook\n    module.exit_json(\n        changed=False,\n        config=config,\n    )\n\nif __name__ == "__main__":\n    main()\n<\/code><\/pre>\n\n\n\n
Dazu geh\u00f6ren einige wohlbekannten Abschnitte:<\/p>\n\n\n\n
  • Erforderliches Werkzeug <strong>AnsibleModule<\/strong> <\/code>ist importiert<\/li>
  • Der Abschnitt mit Inputs, wie er im Ansible-Playbook aufgebaut werden sollte, ist definiert<\/li>
  • Der Abschnitt f\u00fcrs Lesen \u00fcbergebener Parameter in Python aus dem Ansible-Playbook (<strong>addresses<\/strong> <\/code>und address_groups<\/code><\/strong>)<\/li>
  • Gesch\u00e4ftslogik, die eigentlich das macht, was wir wollen, dass das Modul macht (Generierung von Befehlen)<\/li>
  • Verlassen des (Python) Moduls und R\u00fcckgabe der Ergebnisse an das Ansible-Playbook<\/li><\/ul>\n\n\n\n
    Ausf\u00fchren von main.yml<\/code><\/strong> Playbook ergibt folgendes:<\/p>\n\n\n\n
    run<\/strong>   <\/p>\n\n\n\n
    (ansible) devuser@vmi520322:~\/work\/075_ansible_modules_with_classes$ ansible-playbook main.yml \n[WARNING]: No inventory was parsed, only implicit localhost is available\n[WARNING]: provided hosts list is empty, only localhost is available. Note that the implicit localhost does not match 'all'\n\nPLAY [localhost] ****************\n\nTASK [Generate Junos CLI commands] ****************\nok: [localhost]\n\nTASK [Print Junos CLI commands] ****************\nok: [localhost] => {\n    "msg": {\n        "changed": false,\n        "config": [\n            "set security address-book global address ADDRESS_SRC1 10.10.10.0\/24",\n            "set security address-book global address ADDRESS_SRC2 11.11.11.0\/24",\n            "set security address-book global address ADDRESS_DST1 200.200.200.0\/24",\n            "set security address-book global address ADDRESS_DST2 222.222.222.0\/24",\n            "set security address-book global address-set AG_SRC address ADDRESS_SRC1",\n            "set security address-book global address-set AG_SRC address ADDRESS_SRC2",\n            "set security address-book global address-set AG_DST address ADDRESS_DST1",\n            "set security address-book global address-set AG_DST address ADDRESS_DST2"\n        ],\n        "failed": false\n    }\n}\n\nPLAY RECAP ****************\nlocalhost                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0  \n<\/code><\/pre>\n\n\n\n
    Die Ergebnisse sehen gut aus. Die Liste von zur\u00fcckgegebenen Befehlen kann in eine Juniper-Maschine entweder mithilfe von juniper.device.config<\/strong> oder junipernetworks.junos.junos_config<\/strong> Ansible-Modulen aufgeladen werden.<\/p>\n\n\n\n
    Bauen wir nun das ma\u00dfgeschneiderte Ansible-Modul create_junos_config2<\/strong> auf, das genau die gleiche Funktion beh\u00e4lt, aber der Codestil wird anders. Wir werden Python Class verwenden.<\/p>\n\n\n\n
    create_junos_config2.py<\/strong><\/strong>   <\/p>\n\n\n\n
    #!\/usr\/bin\/python\n\nfrom ansible.module_utils.basic import AnsibleModule\n\nclass JunosConfig:\n    def __init__(self, module, addresses, address_groups):\n        # inputs\n        self.module = module\n        self.addresses = addresses\n        self.address_groups = address_groups\n\n        # outputs\n        self.config = []\n\n    def _generate_address_config(self):\n        for addr in self.addresses:\n            cmd = (\n                f"set security address-book global address {addr['name']}"\n                f" {addr['subnet']}"\n            )\n            self.config.append(cmd)\n\n    def _generate_group_config(self):\n        for ag in self.address_groups:\n            for addr in ag["addresses"]:\n                cmd = (\n                    f"set security address-book global address-set {ag['name']}"\n                    f" address {addr}"\n                )\n                self.config.append(cmd)\n\n    def generate_config(self):\n        # Business logic\n        self._generate_address_config()\n        self._generate_group_config()\n\n        # Exit module, back to playbook\n        self.module.exit_json(\n            changed=False,\n            config=self.config,\n        )\n\ndef main():\n    # Define input params\n    inputparams = {\n        "addresses": {"required": True, "type": "list"},\n        "address_groups": {"required": True, "type": "list"},\n    }\n\n    module = AnsibleModule(argument_spec=inputparams)\n\n    juniper_config = JunosConfig(\n        addresses=module.params["addresses"],\n        address_groups=module.params["address_groups"],\n        module=module,\n    )\n\n    juniper_config.generate_config()\n\nif __name__ == "__main__":\n    main()\n<\/code><\/pre>\n\n\n\n
    Hier muss man einige wichtige Details betonen:<\/p>\n\n\n\n