feat: implement transaction handling for upstream and target operations

- Added transaction support in `add_upstream_target`, `remove_upstream`, `remove_upstream_target`, `update_upstream`, and `update_upstream_target` functions to ensure atomicity of operations.
- Updated the `NginxService` to include methods for validating and applying configurations using the agent service.
- Enhanced error handling in agent service interactions, returning appropriate internal server errors when agent communication fails.
- Introduced mock agent service for testing, allowing for simulation of agent interactions without actual network calls.
- Refactored tests to cover scenarios where agent operations fail, ensuring that internal server errors are returned as expected.

apps/api/src/services/nginx.rs

@@ -6,11 +6,21 @@ pub mod upstream;
 
 use std::sync::Arc;
 
-use sea_orm::DatabaseConnection;
+use sea_orm::{DatabaseConnection, DatabaseTransaction};
 
-use crate::services::nginx::upstream::{UpstreamService, UpstreamServiceImpl};
+use crate::{
+    errors::service_error::ServiceError,
+    services::{
+        agent_client::AgentService,
+        nginx::{
+            builder::{NginxConfigBuilder, NginxConfigProvider},
+            upstream::{UpstreamService, UpstreamServiceImpl},
+        },
+    },
+};
 
 pub struct NginxService {
+    #[allow(dead_code)]
     connection: Arc<DatabaseConnection>,
     //
     upstream_service: Arc<dyn UpstreamService>,
@@ -28,4 +38,49 @@ impl NginxService {
     pub fn get_upstream_service(&self) -> Arc<dyn UpstreamService> {
         self.upstream_service.clone()
     }
+
+    #[allow(dead_code)]
+    pub async fn validate_config(
+        &self,
+        agent: Arc<dyn AgentService>,
+        config: &str,
+    ) -> Result<(), ServiceError> {
+        agent.validate(config).await?;
+
+        Ok(())
+    }
+
+    pub async fn apply_changes(
+        &self,
+        agent: Arc<dyn AgentService>,
+        config: &str,
+    ) -> Result<(), ServiceError> {
+        agent.apply(config).await?;
+
+        Ok(())
+    }
+
+    pub async fn generate_config(
+        &self,
+        tx: Option<&mut DatabaseTransaction>,
+    ) -> Result<String, ServiceError> {
+        let mut builder = NginxConfigBuilder::default();
+        self.upstream_service
+            .generate_config(&mut builder, tx)
+            .await?;
+
+        Ok(builder.to_nginx_config(None))
+    }
+
+    pub async fn regenerate_and_apply_config(
+        &self,
+        agent: Arc<dyn AgentService>,
+        tx: Option<&mut DatabaseTransaction>,
+    ) -> Result<(), ServiceError> {
+        let config = self.generate_config(tx).await?;
+
+        self.apply_changes(agent, &config).await?;
+
+        Ok(())
+    }
 }