Generate

loom generate reverse-engineers a reusable module from an existing GitHub PR or GitLab MR. This is the fastest way to turn a manual change you've already made into repeatable automation.

How It Works

You've onboarded a service by hand — created files, edited YAML, opened a PR. Now you want to make it repeatable:

loom generate https://github.com/myorg/gitops-repo/pull/42 \
  -p serviceName=payments \
  -p namespace=fintech

Loom fetches the PR diff and produces a ready-to-use module:

• Added files become templates with {{ .paramName }} replacing the concrete values, including in file and folder names.
• Modified YAML files become strategic merge patches under __functions/patches/.
• Deleted files become shell operations with rm.
• Renamed files become shell operations with mv.

The generated loom.yaml declares all parameters as required and wires up the operations in order.

Example

Given a PR that added these files for the "payments" service in the "fintech" namespace:

src/fintech/payments-app.yaml
argocd/application-payments.yaml

Running:

loom generate https://github.com/myorg/gitops-repo/pull/42 \
  -p serviceName=payments \
  -p namespace=fintech

Produces a module like:

onboard-service/
├── loom.yaml
├── src/
│   └── {{ .namespace }}/
│       └── {{ .serviceName }}-app.yaml
└── argocd/
    └── application-{{ .serviceName }}.yaml

Every occurrence of payments in file contents and paths is replaced with {{ .serviceName }}, and every occurrence of fintech with {{ .namespace }}.

Running the Generated Module

loom run ./onboard-service -p serviceName=billing -p namespace=platform

Same structure, different parameters. What took a PR now takes a command.

Supported Providers

Both GitHub and GitLab are supported:

https://github.com/owner/repo/pull/123
https://gitlab.com/group/repo/-/merge_requests/123
github:owner/repo#123
gitlab:group/repo!123

Authentication

Uses GITHUB_TOKEN / GITLAB_TOKEN environment variables by default. If the token is not set but the gh or glab CLI is installed and authenticated, Loom falls back to it automatically.

Options

Flag	Description
-p, --param key=value	Concrete value to parameterize (repeatable)
-o, --output dir	Output directory (default: current directory)
-n, --name name	Module name (default: derived from PR title)
--token-env VAR	Env var holding the API token
--exclude-git-ops	Skip generating target, commitPush, and pr operations

By default, the generated module is written to the current directory. Use -o to write to a different directory:

loom generate <pr-url> -o ./my-module

Use --exclude-git-ops when you only want the template/patch operations and will handle git operations separately.