enhancement(snmp_exporter): allows using multiple web listen addresses

Signed-off-by: Christian Krause <christian.krause@idiv.de>

roles/snmp_exporter/molecule/alternative/molecule.yml

@@ -3,5 +3,7 @@ provisioner:
   inventory:
     group_vars:
       all:
-        snmp_exporter_web_listen_address: "127.0.0.1:9116"
+        snmp_exporter_web_listen_address:
+          - '127.0.0.1:9116'
+          - '127.0.1.1:9116'
         snmp_exporter_config_file: ${MOLECULE_SCENARIO_DIRECTORY}/templates/snmp.yml

roles/snmp_exporter/molecule/alternative/tests/test_alternative.py

@@ -33,6 +33,9 @@ def test_service(host):
         raise  # Re-raise the original assertion error
 
 
-def test_socket(host):
-    s = host.socket("tcp://127.0.0.1:9116")
-    assert s.is_listening
+@pytest.mark.parametrize("sockets", [
+    "tcp://127.0.0.1:9116",
+    "tcp://127.0.1.1:9116",
+])
+def test_socket(host, sockets):
+    assert host.socket(sockets).is_listening

roles/snmp_exporter/tasks/preflight.yml

@@ -1,4 +1,26 @@
 ---
+
+- name: Assert that used version supports listen address type
+  ansible.builtin.assert:
+    that:
+      - >-
+        snmp_exporter_web_listen_address is string
+        or
+        (
+          snmp_exporter_version is version('0.21.0', '>=') and
+          snmp_exporter_web_listen_address | type_debug == "list"
+        )
+
+- name: Naive assertion of proper listen address
+  ansible.builtin.assert:
+    that:
+      - >-
+        [snmp_exporter_web_listen_address] |
+          flatten |
+          reject('match', '.+:\\d+$') |
+          list |
+          length == 0
+
 - name: Discover latest version
   ansible.builtin.set_fact:
     snmp_exporter_version: "{{ (lookup('url', 'https://api.github.com/repos/prometheus/snmp_exporter/releases/latest', headers=_github_api_headers,

roles/snmp_exporter/templates/snmp_exporter.service.j2

@@ -9,7 +9,16 @@ User=nobody
 Group={{ 'nogroup' if ansible_os_family == 'Debian' else 'nobody' }}
 ExecReload=/bin/kill -HUP $MAINPID
 ExecStart=/usr/local/bin/snmp_exporter \
+{% if snmp_exporter_version is version('0.21.0', '>=') and
+      snmp_exporter_web_listen_address is iterable and
+      snmp_exporter_web_listen_address is not mapping and
+      snmp_exporter_web_listen_address is not string %}
+{%   for address in snmp_exporter_web_listen_address %}
+  --web.listen-address={{ address }} \
+{%   endfor %}
+{% else %}
   --web.listen-address={{ snmp_exporter_web_listen_address }} \
+{% endif %}
   --log.level={{ snmp_exporter_log_level }} \
   --config.file=/etc/snmp_exporter/snmp.yml