nix(loadtest): remove genKeyMaterials

Merge the same code into genTargets, which removes the need to save the
private key to disk and read it again.

nix/tools/generate_targets.py

@@ -62,13 +62,6 @@ def main():
         help="Path to write the generated files",
         type=Path,
     )
-    parser.add_argument(
-        "--private-key",
-        dest="private_key_path",
-        metavar="PRIVATE_KEY_PATH",
-        type=Path,
-        help="Path to the RSA private key file",
-    )
     parser.add_argument(
         "--worst",
         dest="worst",
@@ -81,15 +74,24 @@ def main():
 
     targets_path = args.generated_path / "gen_targets.http"
 
-    rsa_private_key: Optional[jwt.JWK] = None
+    hs = jwt.JWK.from_password(secret_key)
+    rsa = jwt.JWK.generate(kty="RSA", size=4096)
+
+    jwks = jwt.JWKSet()
+    jwks.add(hs)
+    jwks.add(rsa)
+
+    jwks_path = args.generated_path / "gen_jwks.json"
+
+    # Technically, this exports the private keys, because HS does not have the concept
+    # of a public key. This is not a problem for tests, though, PostgREST can verify
+    # tokens with the private key just as well.
+    jwks_path.write_text(jwks.export())
+    print(f"Created JWKSet on {jwks_path}")
 
     nsamples = 500  # per algorithm
     ntargets = 100000
 
-    hs = jwt.JWK.from_password(secret_key)
-    private_key_data = args.private_key_path.read_text()
-    rsa = jwt.JWK.from_json(private_key_data)
-
     print(f"Generating {ntargets} targets...")
 
     now = int(time.time())