Use per-deploy preview hosts under the site root domain.

Build hosts as <userPrefix>-<deploymentNumber>-preview.<rootDomain> from FRONTEND_URL, wire them through ingress/TLS, and open them from the preview API.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/deployments/deployments.service.ts

@@ -6,6 +6,7 @@ import { Deployment } from './entities/deployment.entity';
 import { ApplicationsService } from '../applications/applications.service';
 import { KubernetesService } from '../kubernetes/kubernetes.service';
 import { BuildService, BuildProgress, BuildCancelledError } from '../build/build.service';
+import * as crypto from 'crypto';
 import {
   AppLifecycleStatus,
   DeploymentStatus,
@@ -28,6 +29,16 @@ export class DeploymentsService {
     private clustersService: ClustersService,
   ) {}
 
+  /**
+   * Stable "number" part for preview host, derived from deployment id.
+   * We keep it numeric to match the "<number>" requirement.
+   */
+  private computePreviewNumberFromDeploymentId(deploymentId: string): string {
+    const hashHex = crypto.createHash('sha256').update(deploymentId).digest('hex');
+    const num = parseInt(hashHex.slice(0, 8), 16) % 1_000_000; // 0..999999
+    return String(num).padStart(6, '0');
+  }
+
   async triggerDeployment(applicationId: string, userId: string): Promise<Deployment> {
     const app = await this.applicationsService.findOne(applicationId, userId);
 
@@ -38,13 +49,22 @@ export class DeploymentsService {
       imageTag: `${app.name}:${Date.now()}`,
       status: DeploymentStatus.PENDING,
       version: `v${Date.now()}`,
+      previewSubdomain: null,
     });
     const saved = await this.deploymentsRepository.save(deployment);
 
+    // Fill deterministic preview number after we have the deployment id.
+    let previewSubdomain: string | null = null;
+    if (!app.customDomain) {
+      previewSubdomain = this.computePreviewNumberFromDeploymentId(saved.id);
+      await this.deploymentsRepository.update(saved.id, { previewSubdomain });
+      saved.previewSubdomain = previewSubdomain;
+    }
+
     // Trigger async pipeline (Helm-only for managed services, build+deploy for apps)
     const run = isManagedProductType(app.productType)
       ? this.executeManagedPipeline(saved.id, app)
-      : this.executePipeline(saved.id, app);
+      : this.executePipeline(saved.id, app, previewSubdomain);
     run.catch((error) => {
       this.logger.error(`Pipeline failed for deployment ${saved.id}:`, error);
     });
@@ -137,7 +157,11 @@ export class DeploymentsService {
     }
   }
 
-  private async executePipeline(deploymentId: string, app: any): Promise<void> {
+  private async executePipeline(
+    deploymentId: string,
+    app: any,
+    previewSubdomain: string | null,
+  ): Promise<void> {
     try {
       // Step 1: Build image
       await this.updateStatus(deploymentId, DeploymentStatus.BUILDING);
@@ -159,7 +183,13 @@ export class DeploymentsService {
       });
 
       const hasDbDump = app.dbDumpPath && fs.existsSync(app.dbDumpPath);
-      const { app: deployedApp, k8sResources } = await this.deployWithClusterFallback(deploymentId, app, imageUri, hasDbDump);
+      const { app: deployedApp, k8sResources } = await this.deployWithClusterFallback(
+        deploymentId,
+        app,
+        imageUri,
+        hasDbDump,
+        previewSubdomain,
+      );
       app = deployedApp;
 
       // Step 3.5: Restore DB dump if one was uploaded (must happen after deploy creates the namespace + DB)
@@ -316,6 +346,7 @@ export class DeploymentsService {
     app: any,
     imageUri: string,
     hasDbDump: boolean,
+    previewSubdomain: string | null,
   ): Promise<{ app: any; k8sResources: Record<string, any> }> {
     const failedClusterIds: string[] = [];
     let currentApp = app;
@@ -340,7 +371,9 @@ export class DeploymentsService {
           hasDbDump && !isManagedProductType(currentApp.productType)
             ? { ...currentApp, replicas: 0 }
             : currentApp;
-        const k8sResources = await this.kubernetesService.deployApplication(deployApp, imageUri);
+        const k8sResources = await this.kubernetesService.deployApplication(deployApp, imageUri, {
+          previewNumber: previewSubdomain,
+        });
         return { app: currentApp, k8sResources };
       } catch (error: any) {
         lastError = error;
@@ -618,11 +651,19 @@ export class DeploymentsService {
       imageTag: `${app.name}:${Date.now()}`,
       status: DeploymentStatus.PENDING,
       version: `v${Date.now()}`,
+      previewSubdomain: null,
     });
     const saved = await this.deploymentsRepository.save(deployment);
 
+    let previewSubdomain: string | null = null;
+    if (!app.customDomain) {
+      previewSubdomain = this.computePreviewNumberFromDeploymentId(saved.id);
+      await this.deploymentsRepository.update(saved.id, { previewSubdomain });
+      saved.previewSubdomain = previewSubdomain;
+    }
+
     // Trigger async build & deploy pipeline (same as initial deploy)
-    this.executePipeline(saved.id, app).catch((error) => {
+    this.executePipeline(saved.id, app, previewSubdomain).catch((error) => {
       this.logger.error(`Redeploy pipeline failed for deployment ${saved.id}:`, error);
     });
 

backend/src/deployments/entities/deployment.entity.ts

@@ -33,6 +33,13 @@ export class Deployment {
   @Column({ type: 'text', nullable: true })
   deployLog: string;
 
+  /**
+   * Per-deployment preview number (derived deterministically from deployment.id).
+   * Used to build preview ingress host under the main frontend domain.
+   */
+  @Column({ type: 'varchar', length: 63, nullable: true })
+  previewSubdomain: string | null;
+
   @Column({ nullable: true })
   errorMessage: string;