Load PRIVATE_KEY from .env to PEM-formatted

1. Deserializes the PEM-formatted PRIVATE_KEY to RSA private key object
2. Generate RSA public key object from RSA private key object
3. Serialize the public key from RSA object to PEM-formatted

Author: hankngo

tools/events-automation/.gitignore

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+.env

tools/events-automation/jwt_auth.py

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+import jwt
+import os
+import datetime
+
+from dotenv import load_dotenv
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.backends import default_backend
+
+# Automate loading environment variables in Python script, make them accessible to the project
+load_dotenv()
+
+def get_PEM_private_key():
+    # Load the PRIVATE_KEY in PEM-formatted string from .env to bytes
+    pem_bytes = (os.getenv('PRIVATE_KEY', "")).encode() 
+    return pem_bytes
+
+def get_RSA_private_key():
+    # Deserializes/Loads the private key from PEM-formatted bytes to an RSA private key object, so we could perform cryptographic operations, such as signing data
+    private_key = serialization.load_pem_private_key(
+        get_PEM_private_key(), password=None, backend=default_backend()
+    )
+    return private_key
+
+def get_RSA_public_key():
+    # Get the corresponding RSA public key object from private_key
+    public_key = get_RSA_private_key().public_key()
+    return public_key
+
+def get_PEM_public_key():
+    # Serialize the public key from RSA object to PEM format, to verify digital signatures
+    pem_bytes = (get_RSA_public_key().public_bytes(
+        encoding=serialization.Encoding.PEM,
+        format=serialization.PublicFormat.SubjectPublicKeyInfo
+    )).decode()
+    return pem_bytes