WAL-G — grunt-it fork (adds native age encryption)

This is a fork of wal-g/wal-g maintained by grunt-it. The only addition is a native age crypter. Everything else tracks upstream. See the upstream docs at https://wal-g.readthedocs.io for all other usage.

Why this fork exists

Upstream WAL-G can encrypt backups with PGP, libsodium, or a cloud KMS — but not with age (it's an open feature request: wal-g#1983).

grunt-it's backup/DR architecture standardizes on one asymmetric key — age — for the entire backup surface (control-plane tarballs, WAL segments, and Postgres base backups). age is the right primitive for us because:

• The host can't decrypt what it uploads. A database host holds only the public recipient. A compromised host or leaked bucket credential exposes only ciphertext — the private identity is escrowed in a human-only vault and never touches a server. (libsodium is symmetric → the host could decrypt; PGP would be a second key model to mint/rotate/escrow alongside the age key we already use elsewhere.)
• Multiple recipients, natively. A backup can be encrypted to several recipients at once, and any single identity decrypts it independently. We use this so an unattended restore-drill can decrypt with its own scoped key — proving backups are restorable on a schedule — without ever exposing the human-escrow key.

Rather than bolt age on with a brittle age -r … | wal-g wal-push - shell pipe (which only covers the WAL stream, not base backups, and is awkward to make multi-recipient), we added age as a first-class WAL-G Crypter so it covers WAL and base backups uniformly.

What's added here

• internal/crypto/age/ — an age implementation of WAL-G's crypto.Crypter (Encrypt/Decrypt over io.Writer/io.Reader, backed by filippo.io/age). Pure Go, no cgo, always compiled in (unlike the libsodium crypter, which is cgo + build-tag gated).
• Wiring in internal/configure.go (ConfigureCrypterForSpecificConfig) and four new settings in internal/config/config.go.

Configuration

Setting	Direction	Notes
WALG_AGE_RECIPIENT_FILE	encrypt (upload)	Path to a file with one age recipient per line (multi-recipient).
WALG_AGE_RECIPIENT	encrypt (upload)	Inline recipient(s), newline-separated.
WALG_AGE_IDENTITY_FILE	decrypt (download)	Path to an age identity (AGE-SECRET-KEY-1… or SSH key).
WALG_AGE_IDENTITY	decrypt (download)	Inline identity.

An upload-only host sets only a recipient; a restore sets only an identity. Recipients and identities are independent — any one of the encryption recipients can decrypt.

# Upload, encrypting to two recipients (e.g. human-escrow + a drill key):
printf '%s\n%s\n' "$HUMAN_RECIPIENT" "$DRILL_RECIPIENT" > /etc/walg/age-recipient.pub
export WALG_AGE_RECIPIENT_FILE=/etc/walg/age-recipient.pub
wal-g backup-push "$PGDATA"

# Restore, decrypting with either identity:
export WALG_AGE_IDENTITY_FILE=/etc/walg/age-identity.txt
wal-g backup-fetch /restore/path LATEST

Security notes

• The age recipient (public key) is safe to ship to any host. The identity (private key) is secret — keep it out of hosts/repos; WALG_AGE_IDENTITY is redacted in logs.
• No keys live in this repository. Tests generate ephemeral keys at runtime.

Relationship to upstream

• Tracks wal-g/wal-g (forked at v3.0.8). The age crypter is offered upstream as a PR against wal-g#1983; if it merges, this fork can be retired.
• Apache-2.0, same as upstream (see LICENSE.md). Not affiliated with or endorsed by the WAL-G maintainers.

Building

Same as upstream — the age crypter needs no extra system libraries:

make deps
make pg_build   # produces main/pg/wal-g

Tagged releases (v*) build wal-g-pg for Ubuntu 20.04/22.04/24.04 × amd64/aarch64 and publish SHA256-checksummed binaries (see .github/workflows/release.yml).