Introduction - The Cottage Book

The cottage logo

Cottage is a GitOps tool for teams to manage age-encrypted secrets in git repositories.

It provides a simple workflow to encrypt/decrypt secrets, manage recipients, and keep secrets out of the repo while still allowing for easy sharing via VCS. Cottage also generates redacted previews of encrypted secrets for better visibility and supports both persistent and temporary decryption workflows, while ensuring secrets are never committed in plaintext.

Features
Try in Cottage Lab
Installation
Quick Start
GitOps
Git Hooks
Access Control
1. Rules
2. Verification
Any Provider as Upstream
Learn More
Troubleshooting
Comparison
License

Features

Exposure-safe: Uses Rust’s type system to make sure bugs can never accidentally expose secrets.
Team-friendly: Share public keys (recipients) in the repo, keep private keys (identities) local.
Access Control: Simple allow/deny rules to control which secrets are encrypted for which recipients.
Manages .gitignore: Automatically updates .gitignore to keep unencrypted secrets out of the repo.
Previews: Generates timestamped redacted previews of encrypted secrets for better visibility.
Rich diffs: Keeps git diff clean & reviewable, while ctg diff shows diff of locally modified secrets with tracked encrypted counterparts.
Checksum verification: Prevents tampering by verifying that encrypted secrets and recipient lists match the metadata.
Git hooks: Easily set up git hooks to automatically check/encrypt secrets before commit and decrypt them after checkout.
Persistent secrets workflow: ctg decrypt/edit/sync keeps decrypted secrets on disk.
Temporary secrets workflow: ctg run (shortcut ctgx) decrypts secrets temporarily to run a command, then deletes them regardless of the command’s success or failure.
Environment injection workflow: ctg env injects decrypted secrets as environment variables to run a command, without writing them to disk at all.
Clean up: ctg clean deletes all decrypted secrets from local repo to let you run your AI agents with a tiny bit less worry.
Supports jj and non-git directories: ctg init turns any directory into a secret store.
Sync with any provider: Lets you configure any provider with an API as the upstream, and start using ctg pull/diff/push like git pull/diff/push.

Try in Cottage Lab

Try cottage lab right in your browser without installing anything.

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Installation

# rust cargo-binstall
cargo binstall --locked cottage

# rust cargo
cargo install --locked cottage

# python pip
pip install cottage

# python uv
uv pip install cottage

Also available as docker images:

# Docker
docker run --rm -v $PWD:/app sayanarijit/cottage --version

# Podman
podman run --rm -v $PWD:/app quay.io/sayanarijit/cottage --version

Or download the latest release from GitHub.

Quick Start

Init project:

mkdir project && cd project

git init  # Optional, cottage works better with git but it's not required
ctg init  # Sets up the .cottage directory and necessary files

tree -a
# .
# ├ .cottage/           <- Auto-generated by `ctg init`
# │ ├ identity        <- Your private key, keep it safe. Move it to `~/.config/cottage/identity` to use it globally, or replace it with a soft link to one of your existing private keys.
# │ └ recipients/     <- This is where your team keeps the public keys of all the recipients.
# │     └ sayanarijit <- Your public key. Commit it. To use an existing public key, just copy (don't softlink) that key here.
# ├ .git/...
# ├ .gitattributes      <- Added `*.cott.age binary export-ignore filter=cottage-encrypted -diff` to avoid polluting git diff
# └ .gitignore          <- Added `/.cottage/identity` for obvious reasons

# You can run `ctg clean --all` anytime to clean up everything cottage ever did.

Create or edit a secret.

ctg edit secret.yml --clean    # Opens secret.yml in $EDITOR
ctg encrypt secret.yml --clean # Another way to encrypt secrets
# encrypt secret.yml
#    into secret.yml.cott.age
#    edit secret.yml.cott.toml
#    edit .gitignore
# delete secret.yml

Run a command with temporary decrypted secrets:

cat secret.yml
# cat: secret.yml: No such file or directory

ctg run kubectl apply -f secret.yml          # decrypts secret.yml.cott.age to secret.yml and runs the command
ctg run kubectl apply -f secret.yml.cott.age # also replaces the path argument with the decrypted file path
ctg run kubectl apply -f .                   # decrypts all .cott.age files in . and runs the command
ctg run ./deploy.sh                          # decrypts all .cott.age files in repo and runs the command

cat secret.yml
# cat: secret.yml: No such file or directory

Or use the shortcut:

ctgx ./deploy.sh  # same as ctg run -- ./deploy.sh

Run a command with secrets injected as environment variables, without writing to disk at all:

ctg env -- ./deploy.sh # Export secrets from .env.cott.age (default) without writing them to disk, then run deploy.sh
ctg env -F .env.prod.cott.age -- ./deploy.sh # exports from .env.prod.cott.age instead of .env.cott.age
ctg env -F secrets.json.cott.age -- printenv COTTAGE_SECRET # Also supports non-dotenv files.

GitOps

To share your secrets with team members, just push to the git repo.

git add .
git commit -m "Add secret.yml"
git push origin main

Ask your teammates to add their public keys to .cottage/recipients and push the changes. Then you can pull and re-encrypt the secrets for them.

git pull origin main

ctg sync  # or `ctg decrypt && ctg encrypt`
# encrypt secret.yml
#    into secret.yml.cott.age
#    edit secret.yml.cott.toml

ctg clean  # optional
# delete secret.yml

# review changes, commit and push
git add .
git commit -m "Add new recipient to secrets"
git push origin main

Now your teammates can pull the latest changes and decrypt secrets for themselves.

Git Hooks

You can use prek or pre-commit to set up git hooks to automatically check/encrypt secrets before commit and decrypt them after checkout.

See the example prek configuration here.

Access Control

Rules

In the metadata file, you can annotate which recipients the secret should be encrypted for. This allows you to have different secrets for different environments (e.g. staging vs production) and only encrypt them for the relevant recipients.

# secret.yml.cott.toml
[secret]
allow = ["sayanarijit"]  # Only encrypt for sayanarijit

# secret.yml.cott.toml
[secret]
deny = ["sayanarijit"]  # Encrypt for everyone except sayanarijit

# secret.yml.cott.toml
[secret]
allow = ["env/staging/*"]  # Supports glob patterns, only encrypt for recipients in env/staging
deny = ["env/staging/badservice"]  # Encrypt for everyone in env/staging except badservice

Deny rules take precedence over allow rules.

See metadata specification for more details.

Verification

You can run ctg verify in CI to verify that the encrypted secrets and recipient lists match the metadata rules, to prevent tampering.

# .github/workflows/cottage-verify.yml
name: Cottage Verify
on: [push, pull_request]
permissions:
  contents: read
jobs:
  verify-secrets:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Verify secrets
        run: docker run --rm -v "${{ github.workspace }}:/app" ghcr.io/sayanarijit/cottage verify

Any Provider as Upstream

With cottage, you can sync secrets with any provider that has an API, not just git.

For that, create a file named cottage.toml in the project root and configure the upstream settings.

See the example cottage.toml here and the secret specific upstream configuration here.

The workflow is similar to git, but instead of git pull and git push, you run ctg pull and ctg push to sync secrets with the configured upstream.

Example:

# Pull latest changes into local encrypted secrets
# Similar to `git pull origin`
ctg pull myvault

# Compare diff with local decrypted secrets
ctg diff

# Sync local decrypted secrets with local encrypted secrets
ctg sync

# Push changes from local encrypted secrets to upstream
# Similar to `git push origin main`
ctg push myvault

See upstream configuration specification for more details.

Learn More

See examples directory for more usage examples.

Troubleshooting

# See debug logs with -v, -vv or -vvv
ctg run -vvv -- ./deploy.sh

Auto manage .gitignore to ensure unencrypted secrets are never committed to git.
Encrypted secrets being pure age encrypted .age files, allows for better interoperability with a wider ecosystem of tools.
Cleaner diffs - unlike SOPS, which generates diffs for every value of every secret, even if the actual change is just adding/removing a recipient, cottage only generates one diff per file, explicitly pointing out the change in recipients checksum.

Cottage vs Dotenvx

Cottage borrows the ctg env API from Dotenvx.

Supports any file type, not just dotenv files.
Manages multiple secrets in a repo.
Access control rules to encrypt secrets for specific recipients.
Cleaner diffs - see Cottage vs SOPS.

Cottage vs Agebox

Agebox is very similar to cottage in core philosophy but lacks many features.

License

MIT OR Apache-2.0

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The Cottage Book