## Summary
GCP base templates (`gcp-linux`, `gcp-windows`) in the Template Builder
had a Terraform `variable "project_id"` with no default, but their
`base.json` manifests didn't declare it. The UI never prompted for it,
so the provisioner import always failed with:
```
required template variables need values: project_id
```
## Changes
- Add `project_id` as a required variable in both GCP `base.json`
manifests
- Convert templates from raw Terraform variable blocks to Go template
injection (`{{ .Variables.project_id }}`), matching the existing
kubernetes pattern
- Fix `DefaultBaseRenderContext` to supply a `"REQUIRED"` placeholder
for required variables without defaults (previously rendered as `<no
value>`)
- Replace duplicate test subtests with proper GCP coverage including a
missing-variable error case
<details>
<summary>Implementation plan</summary>
### Root cause
The GCP base templates contained `variable "project_id" {}` (no default
= required) in their `.tf.tmpl` files, but the `base.json` manifests had
an empty `variables` array. The Template Builder UI
(`BaseTemplateParametersStep`) is data-driven from `base.json`, so it
never showed a field for `project_id`. The composed Terraform output
still contained the required variable, causing the provisioner import to
fail.
### Fix approach
Follow the pattern established by the kubernetes base template:
1. Declare variables in `base.json` so the UI prompts for them
2. Use Go template syntax (`{{ .Variables.project_id }}`) to inject
values at compose time
3. Remove raw Terraform `variable` blocks from the template since the
value is now baked in
### Files changed
| File | Change |
|---|---|
| `bases/gcp-linux/base.json` | Added `project_id` as a required
variable |
| `bases/gcp-windows/base.json` | Added `project_id` as a required
variable |
| `bases/gcp-linux/main.tf.tmpl` | Removed Terraform variable block, use
Go template injection |
| `bases/gcp-windows/main.tf.tmpl` | Same |
| `bases.go` | `DefaultBaseRenderContext` supplies placeholder for
required vars without defaults |
| `compose_test.go` | Replaced duplicate subtests with proper GCP tests
|
| `templatebuilder_handler_test.go` | Updated `gcp-windows` spec to
expect `project_id` variable |
| Golden files | Regenerated |
</details>
> 🤖 Generated by Coder Agents on behalf of @jeremyruppel
Add 6 new base templates to the template builder, covering all major
cloud providers and platforms:
- **scratch**: Minimal starter template with only `coder_agent` and
metadata
- **aws-windows**: AWS EC2 Windows instances with PowerShell user_data
- **azure-linux**: Azure VMs with cloud-init and managed disk
persistence
- **gcp-linux**: Google Compute Engine Linux instances with persistent
disk
- **gcp-windows**: Google Compute Engine Windows instances
- **digitalocean-linux**: DigitalOcean Linux droplets with persistent
volumes
Each base includes `base.json`, `main.tf.tmpl`, `README.md` (with
prerequisite markers), and any static files (cloud-init configs). Tests
verify all 9 bases load, render without error, and produce valid
single-agent declarations.
`azure-windows` is deferred; it needs to be registered in the `examples`
package first.
Depends on #26633
> [!NOTE]
> This PR was authored by Coder Agents on behalf of @jeremyruppel.
---
NB: This is very much an agent-generated PR and draws completely from
base templates that exist in `examples/templates/`. The base.json files
are new, so review those, but don't spend any brain tokens on the
correctness of the terraform and supporting files: any issues there are
issues with the upstream example template
Jeremy Ruppel