feat(api): handle build server deployment init gracefully for older cli versionsi (#2526)

This PR adapts the deployment initialization endpoint to handle build server deployments with older CLI versions gracefully.

When we introduced automatic deployments via the build server, we slightly changed the deployment flow
mainly in the initialization and starting step: now deployments are first initialized in the `PENDING` status
and updated to `BUILDING` once the build server dequeues the build job.
Newer versions of the `deploy` command in the CLI will automatically attach to the existing deployment
and continue with the build process. For older versions, we can't change the command's client-side behavior,
so we need to handle this case here in the initialization endpoint. As we control the env variables which
the git meta is extracted from in the build server, we can use those to pass the existing deployment ID
to this endpoint. This doesn't affect the git meta on the deployment as it is set prior to this step using the
/start endpoint. It's a rather hacky solution, but it will do for now as it enables us to avoid degrading the
build server experience for users with older CLI versions. We'll eventually be able to remove this workaround
once we stop supporting 3.x CLI versions.

Author: myftija

apps/webapp/app/v3/services/initializeDeployment.server.ts

@@ -19,7 +19,40 @@ export class InitializeDeploymentService extends BaseService {
     environment: AuthenticatedEnvironment,
     payload: InitializeDeploymentRequestBody
   ) {
-    return this.traceWithEnv("call", environment, async (span) => {
+    return this.traceWithEnv("call", environment, async () => {
+      if (payload.gitMeta?.commitSha?.startsWith("deployment_")) {
+        // When we introduced automatic deployments via the build server, we slightly changed the deployment flow
+        // mainly in the initialization and starting step: now deployments are first initialized in the `PENDING` status
+        // and updated to `BUILDING` once the build server dequeues the build job.
+        // Newer versions of the `deploy` command in the CLI will automatically attach to the existing deployment
+        // and continue with the build process. For older versions, we can't change the command's client-side behavior,
+        // so we need to handle this case here in the initialization endpoint. As we control the env variables which
+        // the git meta is extracted from in the build server, we can use those to pass the existing deployment ID
+        // to this endpoint. This doesn't affect the git meta on the deployment as it is set prior to this step using the
+        // /start endpoint. It's a rather hacky solution, but it will do for now as it enables us to avoid degrading the
+        // build server experience for users with older CLI versions. We'll eventually be able to remove this workaround
+        // once we stop supporting 3.x CLI versions.
+
+        const existingDeploymentId = payload.gitMeta.commitSha;
+        const existingDeployment = await this._prisma.workerDeployment.findFirst({
+          where: {
+            environmentId: environment.id,
+            friendlyId: existingDeploymentId,
+          },
+        });
+
+        if (!existingDeployment) {
+          throw new ServiceValidationError(
+            "Existing deployment not found during deployment initialization"
+          );
+        }
+
+        return {
+          deployment: existingDeployment,
+          imageRef: existingDeployment.imageReference ?? "",
+        };
+      }
+
       if (payload.type === "UNMANAGED") {
         throw new ServiceValidationError("UNMANAGED deployments are not supported");
       }