feat(get-facts): node creation_date

Extract the node creation date by looking at the birth date of some
files, created at NS8 installation time.

Using system's "stat" command because it provides better filesystem
birth date compatibility than Python 3.11.

Author: DavidePrincipi

core/imageroot/var/lib/nethserver/node/actions/get-facts/50get

@@ -17,13 +17,27 @@ import subprocess
 import agent.volumes
 import agent.facts
 import ansible_runner
-
+from datetime import datetime, timezone
 
 def _run(cmd):
     proc = subprocess.run(cmd, shell=True, check=True,
                           capture_output=True, text=True)
     return proc.stdout.rstrip().lstrip()
 
+def _node_creation_date():
+    # Read birth dates of files created during NS8 installation.
+    try:
+        output = subprocess.check_output(["stat", r"--printf='%Y\n%W\n'",
+                "/etc/nethserver/wg0.pub",
+                "/var/lib/nethserver/node/state/agent.env"
+            ],
+            text=True,
+        )
+        timestamps = [int(x) for x in filter(str.isnumeric, output.split())]
+        creation_time = min(timestamps) # Consider the older value
+    except subprocess.CalledProcessError:
+        creation_time = 0
+    return datetime.fromtimestamp(creation_time, tz=timezone.utc).isoformat()
 
 def _get_core_version():
     with open('/etc/nethserver/core.env', encoding='utf-8') as file:
@@ -94,6 +108,7 @@ leader_id = rdb.hget("cluster/environment", "NODE_ID")
 json.dump(
     {
         os.environ['AGENT_ID'].removeprefix('node/'): {
+            'creation_date': _node_creation_date(),
             'cluster_leader': leader_id == os.getenv("NODE_ID"),
             'fqdn': agent.facts.pseudo_domain(facts['ansible_fqdn']),
             'default_ipv4': agent.facts.pseudo_ip(facts.get('ansible_default_ipv4', {}).get('address', '')),