Web previews - Towbar

Related reading: Previews. These are separate files in one repository. A shared Docker network works only when the workloads run on the same server; Towbar does not automatically order their deployments or copy secret values between them.

Towbar manifests

version: 2
environments:
  production:
    previews:
      enabled: true

id: pull-request-preview-for-web-api
name: Web previews
deployment:
  type: dockerfile
  context: .
  dockerfile: Dockerfile
container:
  port: 3000
  network: application
health:
  path: /health
environments:
  production:
    server: 192.0.2.10
preview:
  enabled: true
  domain: preview.example.com
  ttlHours: 72

Configure

Register and prepare the example server or servers, connect the repository, and map production to the branch containing these files.
Configure preview DNS and isolated preview secrets, then verify a pull request creates a separate preview workload.
Sync the repository, inspect the resolved configuration, deploy manually, and perform the verification below before enabling automation.

Verify

Preview secrets are isolated; do not assume a Datastore is cloned for each PR. For field constraints, see Service manifest.

Last modified on September 27, 2026