Add helper for per-user age keys

docs/secrets.md

@@ -30,3 +30,12 @@ This decrypts `creds/secrets.enc.env` to `creds/secrets.env` if needed (requires
 - Generate a new age key: `age-keygen -o creds/age-key.txt` (keep old backup if you need to reencrypt).
 - Update `.sops.yaml` recipient to the new public key.
 - Re-encrypt: `SOPS_AGE_KEY_FILE=creds/age-key.txt sops --encrypt --in-place creds/secrets.enc.env`.
+
+## Per-user age keys
+- Keys live under `creds/age/<user>.key` (git-ignored) and carry a public key in the header.
+- Helper: `./scripts/manage-age-key.sh add alice` generates a key and appends the recipient to `.sops.yaml`.
+- Remove: `./scripts/manage-age-key.sh remove alice` deletes the key file and strips the recipient (re-encrypt afterwards).
+- List: `./scripts/manage-age-key.sh list`.
+- After adding/removing recipients, re-encrypt secrets: `sops --encrypt --in-place creds/secrets.enc.env`.
+
+Share each user’s private key securely (password manager). Multiple recipients in `.sops.yaml` allow any listed user to decrypt.

scripts/manage-age-key.sh

@@ -0,0 +1,114 @@
+#!/usr/bin/env bash
+# Manage per-user age keys and sops recipients.
+# - Creates a new age keypair under creds/age/<user>.key
+# - Updates .sops.yaml recipients list for creds/secrets.enc.env
+# - Can delete a user (removes key file and recipient entry)
+#
+# Usage:
+#   ./scripts/manage-age-key.sh add <username>
+#   ./scripts/manage-age-key.sh remove <username>
+#   ./scripts/manage-age-key.sh list
+#
+# Notes:
+# - Keep private keys out of git; creds/age/ is git-ignored.
+# - After add/remove, re-encrypt secrets: sops --encrypt --in-place creds/secrets.enc.env
+
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+AGE_DIR="$ROOT_DIR/creds/age"
+SOPS_CONFIG="$ROOT_DIR/.sops.yaml"
+
+usage() {
+  sed -n '1,12p' "${BASH_SOURCE[0]}"
+  exit 1
+}
+
+list_keys() {
+  if [[ -d "$AGE_DIR" ]]; then
+    find "$AGE_DIR" -maxdepth 1 -type f -name '*.key' -printf '%f\n'
+  fi
+}
+
+ensure_age_dir() {
+  mkdir -p "$AGE_DIR"
+}
+
+add_user() {
+  local user="$1"
+  ensure_age_dir
+  local key_file="$AGE_DIR/${user}.key"
+  if [[ -f "$key_file" ]]; then
+    echo "Key already exists: $key_file"
+    exit 1
+  fi
+  echo "Generating age key for ${user} -> ${key_file}"
+  age-keygen -o "$key_file" >/dev/null
+  local pub
+  pub=$(grep '^# public key:' "$key_file" | awk '{print $4}')
+  echo "Public key: $pub"
+
+  if [[ ! -f "$SOPS_CONFIG" ]]; then
+    echo "sops config not found at $SOPS_CONFIG; skipping recipient update."
+    echo "Add this recipient manually: $pub"
+    exit 0
+  fi
+
+  if grep -q "$pub" "$SOPS_CONFIG"; then
+    echo "Recipient already present in $SOPS_CONFIG"
+  else
+    echo "Adding recipient to $SOPS_CONFIG"
+    # Append under the first age key list.
+    tmp=$(mktemp)
+    awk -v pub="$pub" '
+      /^ *- age:/ { in_age=1; print; next }
+      in_age && /^ *- age1/ { print "          - " pub; in_age=0 }
+      { print }
+    ' "$SOPS_CONFIG" >"$tmp"
+    mv "$tmp" "$SOPS_CONFIG"
+  fi
+
+  echo "Done. Re-encrypt secrets after updating recipients:"
+  echo "  sops --encrypt --in-place creds/secrets.enc.env"
+}
+
+remove_user() {
+  local user="$1"
+  local key_file="$AGE_DIR/${user}.key"
+  if [[ -f "$key_file" ]]; then
+    rm -f "$key_file"
+    echo "Removed key $key_file"
+  else
+    echo "No key file for $user at $key_file"
+  fi
+  if [[ -f "$SOPS_CONFIG" ]]; then
+    local pub
+    pub=$(grep '^# public key:' "$key_file" 2>/dev/null | awk '{print $4}')
+    if [[ -n "${pub:-}" ]]; then
+      tmp=$(mktemp)
+      awk -v pub="$pub" '!($0 ~ pub)' "$SOPS_CONFIG" >"$tmp"
+      mv "$tmp" "$SOPS_CONFIG"
+      echo "Removed recipient from $SOPS_CONFIG (if present)."
+    fi
+  fi
+  echo "Re-encrypt secrets to drop removed recipients if needed:"
+  echo "  sops --encrypt --in-place creds/secrets.enc.env"
+}
+
+cmd="${1:-}"
+case "$cmd" in
+  add)
+    [[ $# -eq 2 ]] || usage
+    add_user "$2"
+    ;;
+  remove|rm|delete)
+    [[ $# -eq 2 ]] || usage
+    remove_user "$2"
+    ;;
+  list|ls)
+    list_keys
+    ;;
+  *)
+    usage
+    ;;
+esac