Add GST operator agent localhost certificate generator

app/modules/accounting/gst_operator_agent_runtime/generate_localhost_cert.py

@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+import ipaddress
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+from cryptography import x509
+from cryptography.hazmat.primitives import hashes, serialization
+from cryptography.hazmat.primitives.asymmetric import rsa
+from cryptography.x509.oid import NameOID
+
+ROOT = Path(__file__).resolve().parent
+CERT_PEM = ROOT / "localhost-cert.pem"
+KEY_PEM = ROOT / "localhost-key.pem"
+CERT_DER = ROOT / "localhost-cert.cer"
+
+
+def main() -> None:
+    key = rsa.generate_private_key(public_exponent=65537, key_size=2048)
+    name = x509.Name([
+        x509.NameAttribute(NameOID.COMMON_NAME, "ARRR GST Operator Agent localhost"),
+        x509.NameAttribute(NameOID.ORGANIZATION_NAME, "ARRR & Associates"),
+    ])
+    now = datetime.now(timezone.utc)
+    cert = (
+        x509.CertificateBuilder()
+        .subject_name(name)
+        .issuer_name(name)
+        .public_key(key.public_key())
+        .serial_number(x509.random_serial_number())
+        .not_valid_before(now - timedelta(days=1))
+        .not_valid_after(now + timedelta(days=825))
+        .add_extension(
+            x509.SubjectAlternativeName([
+                x509.DNSName("localhost"),
+                x509.IPAddress(ipaddress.ip_address("127.0.0.1")),
+            ]),
+            critical=False,
+        )
+        .add_extension(x509.BasicConstraints(ca=False, path_length=None), critical=True)
+        .add_extension(
+            x509.ExtendedKeyUsage([x509.oid.ExtendedKeyUsageOID.SERVER_AUTH]),
+            critical=False,
+        )
+        .sign(key, hashes.SHA256())
+    )
+    KEY_PEM.write_bytes(
+        key.private_bytes(
+            encoding=serialization.Encoding.PEM,
+            format=serialization.PrivateFormat.TraditionalOpenSSL,
+            encryption_algorithm=serialization.NoEncryption(),
+        )
+    )
+    CERT_PEM.write_bytes(cert.public_bytes(serialization.Encoding.PEM))
+    CERT_DER.write_bytes(cert.public_bytes(serialization.Encoding.DER))
+
+
+if __name__ == "__main__":
+    main()