asusmini: resolve agenix rules explicitly during cutover

scripts/upgrade-knot.sh

@@ -151,7 +151,8 @@ trap 'exit 143' TERM
 
 umask 077
 runtime=$(mktemp -d "$runtime_template")
-agenix -d "$repo/secrets/knot-env.age" -i "$ssh_key" > "$runtime/knot.env"
+AGENIX_RULES="$repo/secrets/secrets.nix" \
+  agenix -d knot-env.age -i "$ssh_key" > "$runtime/knot.env"
 chmod 0400 "$runtime/knot.env"
 master_key=""
 export -n master_key

tests/test_agenix_rules.py

@@ -0,0 +1,47 @@
+import os
+import shutil
+import subprocess
+import tempfile
+import unittest
+from pathlib import Path
+
+
+@unittest.skipUnless(
+    all(shutil.which(tool) for tool in ("agenix", "age", "ssh-keygen")),
+    "requires agenix, age, and ssh-keygen on PATH",
+)
+class AgenixRulesTests(unittest.TestCase):
+    def test_decrypt_from_outside_rules_directory(self):
+        with tempfile.TemporaryDirectory(prefix="agenix-rules-test-") as raw:
+            root = Path(raw)
+            secrets = root / "secrets"
+            secrets.mkdir()
+            elsewhere = root / "elsewhere"
+            elsewhere.mkdir()
+            key = root / "identity"
+            subprocess.run(
+                ["ssh-keygen", "-q", "-t", "ed25519", "-N", "", "-f", str(key)],
+                check=True,
+            )
+            public_key = key.with_suffix(".pub").read_text().strip()
+            rules = secrets / "secrets.nix"
+            rules.write_text(
+                '{ "knot-env.age".publicKeys = [ "' + public_key + '" ]; }\n'
+            )
+            plaintext = b"KNOT_MASTER_KEY=" + b"A" * 43 + b"=\n"
+            encrypted = subprocess.run(
+                ["age", "-r", public_key], input=plaintext, capture_output=True, check=True
+            )
+            (secrets / "knot-env.age").write_bytes(encrypted.stdout)
+            result = subprocess.run(
+                ["agenix", "-d", "knot-env.age", "-i", str(key)],
+                cwd=elsewhere,
+                env={**os.environ, "AGENIX_RULES": str(rules)},
+                capture_output=True,
+                check=True,
+            )
+            self.assertEqual(result.stdout, plaintext)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_upgrade_knot.py

@@ -97,6 +97,9 @@ elif name == "ssh-keyscan":
 elif name == "nix-env":
     pass
 elif name == "agenix":
+    rules = os.environ.get("AGENIX_RULES", "")
+    if not Path(rules).is_file() or args[:2] != ["-d", "knot-env.age"]:
+        raise SystemExit("agenix needs explicit rules and a rules-relative secret name")
     value = (b"KNOT_MASTER_KEY=" + (b"B" * 43 + b"=\n" if not fail("BAD_KEY") else b"bad\n"))
     sys.stdout.buffer.write(value)
     target = os.environ.get("AGENIX_TARGET")
@@ -195,6 +198,7 @@ class UpgradeKnotTests(unittest.TestCase):
         self.repo = self.tmp / "repo"
         (self.repo / "secrets").mkdir(parents=True)
         (self.repo / "secrets" / "knot-env.age").write_text("not a secret used by fixture\n")
+        (self.repo / "secrets" / "secrets.nix").write_text("{}\n")
         self.source = self.tmp / "git"
         self.source.mkdir()
         (self.source / "knotserver.db").write_text("fixture db\n")