feat: add incus auto-client certificate trust

- add fact to export vault public cert from agents
- add fact to export list of trusted incus client certs
- add method for incus clients to export their client cert to be trusted

modules/incus/manifests/client.pp

@@ -0,0 +1,16 @@
+# incus::client
+#
+# This class configures a host as an incus client and exports its certificate
+# for automatic trust management on incus servers.
+#
+class incus::client {
+
+  # Export this client's certificate for collection by incus servers
+  @@incus::client_cert { $facts['networking']['fqdn']:
+    hostname    => $facts['networking']['fqdn'],
+    certificate => $facts['vault_cert_content'],
+    fingerprint => $facts['vault_cert_fingerprint'],
+    tag         => 'incus_client',
+  }
+
+}

modules/incus/manifests/client_cert.pp

@@ -0,0 +1,41 @@
+# Define the exported resource type for incus client certificates
+define incus::client_cert (
+  String $hostname,
+  Optional[String] $certificate = undef,
+  Optional[String] $fingerprint = undef,
+) {
+
+  # Only proceed if we have both certificate and fingerprint
+  if $certificate and $fingerprint {
+
+    $trust_list = $facts['incus_trust_list']
+    $existing_client = $trust_list.filter |$client| { $client['name'] == $hostname }
+
+    if $existing_client.empty {
+      # Add new certificate
+      exec { "incus_trust_add_${hostname}":
+        path    => ['/bin', '/usr/bin'],
+        command => "echo '${certificate}' > /tmp/${hostname}.crt && \
+                    incus config trust add-certificate /tmp/${hostname}.crt --name ${hostname} && \
+                    rm -f /tmp/${hostname}.crt",
+        unless  => "incus config trust list --format=json | grep '\"name\":\"${hostname}\"'",
+      }
+    } else {
+      # Check if fingerprints are different
+      $existing_fingerprint = $existing_client[0]['fingerprint']
+
+      if $existing_fingerprint != $fingerprint {
+        # Remove existing and add new certificate only if fingerprints differ
+        exec { "incus_trust_update_${hostname}":
+          path    => ['/bin', '/usr/bin'],
+          command => "incus config trust remove ${existing_fingerprint} && \
+                      echo '${certificate}' > /tmp/${hostname}.crt && \
+                      incus config trust add-certificate /tmp/${hostname}.crt --name ${hostname} && \
+                      rm -f /tmp/${hostname}.crt",
+          onlyif  => "incus config trust list --format=json | grep '${existing_fingerprint}'",
+        }
+      }
+      # If fingerprints match, do nothing (certificate is already correct)
+    }
+  }
+}

modules/incus/manifests/init.pp

@@ -92,5 +92,10 @@ class incus (
         }
       }
     }
+
+    # Collect exported client certificates and manage trust
+    Incus::Client_cert <<| tag == 'incus_client' |>> {
+      require => Service['incus'],
+    }
   }
 }