Add `--template` flag to `sc cicd generate` for selective workflow generation

[alex-y-su]

Summary

Extend sc cicd generate with a --template flag to allow generating specific workflow types (e.g., only pr-preview), rather than generating all configured templates at once.

Background

Simple Container is a cloud-agnostic deployment tool that simplifies microservice deployment across AWS, GCP, and Kubernetes. It provides:

• Infrastructure-as-Code using lightweight YAML configurations
• Automated deployments via sc deploy command
• GitHub Actions integration via sc cicd generate
• Secrets management with sc secrets commands

Currently, sc cicd generate generates all workflow types configured in server.yaml under workflow-generation.templates. This feature request proposes adding a --template flag to selectively generate specific workflows.

Motivation

PR preview environments are critical for modern development workflows:

1. Code Review Quality - Reviewers can test changes in a live environment before approving
2. Faster Feedback Loops - Developers see their changes deployed without waiting for merge
3. Reduced Production Risks - Issues are caught earlier in isolated environments
4. Stakeholder Demos - Non-technical stakeholders can preview features via unique URLs

Being able to generate just the pr-preview workflow independently would be useful for:

• Teams adding PR previews to an existing CI/CD setup
• Iterating on preview workflow configuration without regenerating all workflows
• Documentation and onboarding examples

Proposed Solution

Extended Command: sc cicd generate --template

# Generate only PR preview workflow for a stack
sc cicd generate --stack myorg/myapp --template pr-preview

# Generate multiple specific templates
sc cicd generate --stack myorg/myapp --template deploy --template pr-preview

# Dry run to preview what would be generated
sc cicd generate --stack myorg/myapp --template pr-preview --dry-run

# Generate all templates (current behavior, unchanged)
sc cicd generate --stack myorg/myapp

Available Templates

The --template flag would accept any of the existing workflow templates:

Template	Description
deploy	Deploy stack on push to main/default branch
destroy	Destroy stack (with confirmation)
destroy-parent	Destroy parent infrastructure stack
provision	Provision infrastructure resources
pr-preview	Deploy ephemeral preview environments for PRs

PR Preview Workflow Features

The generated pr-preview workflow includes:

Feature	Description
Label-triggered deploys	Deploy only when a specific label (e.g., deploy-preview) is added to PR
Automatic cleanup	Destroy preview environment when PR is closed/merged
Dynamic URLs	Generate unique URLs like pr-123.preview.myapp.com
PR comments	Automatically comment with preview URL and cleanup status

Generated PR Preview Workflow Behavior

PR Opened/Updated + "deploy-preview" label
    │
    ▼
┌─────────────────────┐
│ Deploy Preview Env  │
│ - Build container   │
│ - Deploy to cloud   │
│ - Create DNS record │
└─────────────────────┘
    │
    ▼
┌─────────────────────┐
│ Comment on PR       │
│ "Preview: https://  │
│  pr-123.app.com"    │
└─────────────────────┘

PR Closed/Merged
    │
    ▼
┌─────────────────────┐
│ Destroy Preview Env │
│ - Remove resources  │
│ - Delete DNS record │
│ - Comment cleanup   │
└─────────────────────┘

Configuration in server.yaml

To enable PR preview workflow generation, configure a preview environment and include pr-preview in templates:

cicd:
  type: github-actions
  config:
    organization: "my-company"

    environments:
      staging:
        type: staging
        auto-deploy: true

      production:
        type: production
        protection: true

      # Preview environment for PR deployments
      preview:
        type: preview
        protection: false
        auto-deploy: true
        runner: "ubuntu-latest"
        pr-preview:
          label-trigger: "deploy-preview"
          domain-base: "preview.myapp.com"

    workflow-generation:
      enabled: true
      templates: ["deploy", "destroy", "pr-preview"]  # Include pr-preview

Benefits

For Developers

• Generate only the workflow needed: sc cicd generate --template pr-preview
• Quick iteration on preview configuration
• No need to regenerate all workflows when updating one

For DevOps

• Selective workflow updates without touching production workflows
• Easier migration path for adding PR previews to existing setups
• Fine-grained control over generated files

For Organizations

• Improved code review process with live previews
• Faster release cycles
• Reduced production incidents

Alternatives Considered

1. Generate all templates always - Current behavior; works but forces regeneration of all workflows
2. Separate sc cicd preview command - Adds complexity; extending existing command is simpler
3. Manual workflow creation - Error-prone and requires GitHub Actions expertise

Additional Context

Related Documentation

• Simple Container Installation Guide
• Deployment Types
• Deploying Microservices

Similar Features in Other Tools

• Vercel Preview Deployments
• Netlify Deploy Previews
• Railway PR Environments
• Render Pull Request Previews

Implementation Notes

The existing codebase already has:

• PR preview template in pkg/clouds/github/templates.go:346 (prPreviewTemplate)
• Template loading in pkg/clouds/github/workflow_generator.go:52-58 (LoadTemplates())
• Available templates via GetWorkflowTemplateNames(): ["deploy", "destroy", "destroy-parent", "provision", "pr-preview"]
• Generate command in pkg/cmd/cmd_cicd/cmd_generate.go

Suggested Implementation

1. Add --template flag to cmd_generate.go:

cmd.Flags().StringSliceVar(&params.Templates, "template", []string{},
    "Generate specific templates only (e.g., --template pr-preview). Can be specified multiple times.")

2. Extend GenerateParams in pkg/assistant/cicd/service.go:

type GenerateParams struct {
    // ... existing fields ...
    Templates []string  // Filter to generate only these templates
}

3. Filter templates in WorkflowGenerator.GenerateWorkflows():

templatesToGenerate := wg.config.WorkflowGeneration.Templates
if len(filterTemplates) > 0 {
    // Validate and use only specified templates
    templatesToGenerate = filterTemplates
}