fix: merge existing services in load balancer config

opnsense-config/src/config/manager/ssh.rs

@@ -29,8 +29,7 @@ impl SshConfigManager {
 
         self.opnsense_shell
             .exec(&format!(
-                "cp /conf/config.xml /conf/backup/{}",
-                backup_filename
+                "cp /conf/config.xml /conf/backup/{backup_filename}"
             ))
             .await
     }

opnsense-config/src/modules/load_balancer.rs

@@ -40,21 +40,87 @@ impl<'a> LoadBalancerConfig<'a> {
         self.with_haproxy(|haproxy| haproxy.general.enabled = enabled as i32);
     }
 
-    pub fn add_backend(&mut self, backend: HAProxyBackend) {
+    /// Adds or updates a backend pool.
+    /// If a backend with the same name exists, it is updated. Otherwise, it is added.
+    pub fn add_backend(&mut self, mut backend: HAProxyBackend) {
         warn!("TODO make sure this new backend does not refer non-existing entities like servers or health checks");
-        self.with_haproxy(|haproxy| haproxy.backends.backends.push(backend));
+        self.with_haproxy(|haproxy| {
+            let existing_backend = haproxy
+                .backends
+                .backends
+                .iter_mut()
+                .find(|b| b.name == backend.name);
+
+            if let Some(existing_backend) = existing_backend {
+                backend.uuid = existing_backend.uuid.clone(); // This breaks the `frontend` config
+                                                              // as it is now relying on a stale uuid
+                backend.id = existing_backend.id.clone();
+                *existing_backend = backend;
+            } else {
+                haproxy.backends.backends.push(backend);
+            }
+        });
     }
 
-    pub fn add_frontend(&mut self, frontend: Frontend) {
-        self.with_haproxy(|haproxy| haproxy.frontends.frontend.push(frontend));
+    /// Adds or updates a frontend.
+    /// If a frontend with the same name exists, it is updated. Otherwise, it is added.
+    pub fn add_frontend(&mut self, mut frontend: Frontend) {
+        self.with_haproxy(|haproxy| {
+            let existing_frontend = haproxy
+                .frontends
+                .frontend
+                .iter_mut()
+                .find(|f| f.name == frontend.name);
+
+            if let Some(existing_frontend) = existing_frontend {
+                frontend.uuid = existing_frontend.uuid.clone();
+                frontend.id = existing_frontend.id.clone();
+                *existing_frontend = frontend;
+            } else {
+                haproxy.frontends.frontend.push(frontend);
+            }
+        });
     }
 
-    pub fn add_healthcheck(&mut self, healthcheck: HAProxyHealthCheck) {
-        self.with_haproxy(|haproxy| haproxy.healthchecks.healthchecks.push(healthcheck));
+    /// Adds or updates a health check.
+    /// If a health check with the same name exists, it is updated. Otherwise, it is added.
+    pub fn add_healthcheck(&mut self, mut healthcheck: HAProxyHealthCheck) {
+        self.with_haproxy(|haproxy| {
+            let existing_healthcheck = haproxy
+                .healthchecks
+                .healthchecks
+                .iter_mut()
+                .find(|h| h.name == healthcheck.name);
+
+            if let Some(existing_check) = existing_healthcheck {
+                healthcheck.uuid = existing_check.uuid.clone();
+                *existing_check = healthcheck;
+            } else {
+                haproxy.healthchecks.healthchecks.push(healthcheck);
+            }
+        });
     }
 
-    pub fn add_servers(&mut self, mut servers: Vec<HAProxyServer>) {
-        self.with_haproxy(|haproxy| haproxy.servers.servers.append(&mut servers));
+    /// Adds or updates a list of servers to the HAProxy configuration.
+    /// If a server with the same name already exists, it is updated. Otherwise, it is added.
+    pub fn add_servers(&mut self, servers: Vec<HAProxyServer>) {
+        self.with_haproxy(|haproxy| {
+            for server in servers {
+                let existing_server = haproxy
+                    .servers
+                    .servers
+                    .iter_mut()
+                    .find(|s| s.name == server.name);
+
+                if let Some(existing_server) = existing_server {
+                    existing_server.address = server.address;
+                    existing_server.port = server.port;
+                    existing_server.enabled = server.enabled;
+                } else {
+                    haproxy.servers.servers.push(server);
+                }
+            }
+        });
     }
 
     pub async fn reload_restart(&self) -> Result<(), Error> {