Adds Download endpoint for client bundle

src/main/java/com/litoralregas/openvpn/openvpn/OpenVpnBundleDownload.java

@@ -0,0 +1,10 @@
+package com.litoralregas.openvpn.openvpn;
+
+import java.io.InputStream;
+
+public record OpenVpnBundleDownload(
+        String filename,
+        long size,
+        InputStream inputStream
+) {
+}

src/main/java/com/litoralregas/openvpn/openvpn/OpenVpnService.java

@@ -137,4 +137,13 @@ public class OpenVpnService {
 
         return sshService.executeOnConfiguredVps(command);
     }
+
+    public OpenVpnBundleDownload downloadClientBundle(String clientName) {
+        String filename = clientName + ".tar.gz";
+
+        return sshService.downloadFileFromConfiguredVps(
+                "/var/litoral_regas_openvpn/clients/" + filename,
+                filename
+        );
+    }
 }

src/main/java/com/litoralregas/openvpn/router/RouterController.java

@@ -7,6 +7,10 @@ import com.litoralregas.openvpn.openvpn.IpAllocationService;
 import com.litoralregas.openvpn.openvpn.OpenVpnService;
 import com.litoralregas.openvpn.ssh.SshService;
 import jakarta.validation.Valid;
+import org.springframework.core.io.InputStreamResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
@@ -18,14 +22,12 @@ public class RouterController {
 
     private final RouterService service;
     private final DeploymentService deploymentService;
-    private final SshService sshService;
     private final IpAllocationService ipAllocationService;
     private final OpenVpnService openVpnService;
 
-    public RouterController(RouterService service, DeploymentService deploymentService, SshService sshService, IpAllocationService ipAllocationService, OpenVpnService openVpnService) {
+    public RouterController(RouterService service, DeploymentService deploymentService, IpAllocationService ipAllocationService, OpenVpnService openVpnService) {
         this.service = service;
         this.deploymentService = deploymentService;
-        this.sshService = sshService;
         this.ipAllocationService = ipAllocationService;
         this.openVpnService = openVpnService;
     }
@@ -45,7 +47,6 @@ public class RouterController {
         return service.findById(id);
     }
 
-
     @DeleteMapping("/{id}")
     public void delete(@PathVariable UUID id) {
         service.delete(id);
@@ -154,4 +155,28 @@ public class RouterController {
             return DeploymentResponse.from(failed);
         }
     }
+
+    @GetMapping("/{id}/bundle")
+    public ResponseEntity<InputStreamResource> downloadBundle(@PathVariable UUID id) {
+        Router router = service.findById(id);
+
+        if (router.getStatus() != RouterStatus.PROVISIONED) {
+            throw new IllegalStateException("Router is not provisioned yet");
+        }
+
+        var allocation = ipAllocationService.findByRouterId(id);
+
+        var bundle = openVpnService.downloadClientBundle(
+                allocation.getClientName()
+        );
+
+        return ResponseEntity.ok()
+                .header(
+                        HttpHeaders.CONTENT_DISPOSITION,
+                        "attachment; filename=\"" + bundle.filename() + "\""
+                )
+                .contentType(MediaType.APPLICATION_OCTET_STREAM)
+                .contentLength(bundle.size())
+                .body(new InputStreamResource(bundle.inputStream()));
+    }
 }

src/main/java/com/litoralregas/openvpn/ssh/SshService.java

@@ -1,14 +1,19 @@
 package com.litoralregas.openvpn.ssh;
 
 import com.jcraft.jsch.*;
+import com.litoralregas.openvpn.openvpn.OpenVpnBundleDownload;
 import org.springframework.stereotype.Service;
 
 import java.io.ByteArrayOutputStream;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 
 @Service
 public class SshService {
     private final VpsSshProperties properties;
+
     public SshService(VpsSshProperties properties) {
         this.properties = properties;
     }
@@ -23,6 +28,70 @@ public class SshService {
         );
     }
 
+    public OpenVpnBundleDownload downloadFileFromConfiguredVps(
+            String remotePath,
+            String filename
+    ) {
+        return downloadFile(
+                properties.getHost(),
+                properties.getPort(),
+                properties.getUsername(),
+                properties.getPassword(),
+                remotePath,
+                filename
+        );
+    }
+
+    public OpenVpnBundleDownload downloadFile(
+            String host,
+            int port,
+            String username,
+            String password,
+            String remotePath,
+            String filename
+    ) {
+        try {
+            JSch jsch = new JSch();
+
+            Session session = jsch.getSession(username, host, port);
+            session.setPassword(password);
+            session.setConfig("StrictHostKeyChecking", "no");
+            session.connect(10_000);
+
+            ChannelSftp channel = (ChannelSftp) session.openChannel("sftp");
+            channel.connect(10_000);
+
+            SftpATTRS attrs = channel.lstat(remotePath);
+            long size = attrs.getSize();
+
+            InputStream inputStream = channel.get(remotePath);
+
+            InputStream wrapped = new FilterInputStream(inputStream) {
+                @Override
+                public void close() throws IOException {
+                    try {
+                        super.close();
+                    } finally {
+                        channel.disconnect();
+                        session.disconnect();
+                    }
+                }
+            };
+
+            return new OpenVpnBundleDownload(
+                    filename,
+                    size,
+                    wrapped
+            );
+
+        } catch (Exception e) {
+            throw new IllegalStateException(
+                    "Failed to download file from VPS: " + remotePath,
+                    e
+            );
+        }
+    }
+
     public SshCommandResult execute(
             String host,
             int port,