Some testing with raise -calls.

btc_tracker/kraken_fetch.py

@@ -33,7 +33,6 @@ server_public_key = server_private_key.get_verifying_key()
 # We need the hexadecimal form for sharing over http/json
 server_public_key_hex = binascii.hexlify(server_public_key.to_string()).decode("utf-8")
 
-database_lock = threading.Lock()
 
 # Empty response json
 empty_dict = {
@@ -51,10 +50,32 @@ empty_json = json.dumps(empty_dict)
 
 
 def read_keys():
-    with open(KEYSFILE, "r") as cfile:
-        user_keys = json.load(cfile)
-        return user_keys["user_publickeys"]
+    """
+    Reads the declared KEYSFILE and returns "user_publickeys" from it.
+    Returns: json object
+    """
+    # test if the file is there, we could make one if there is non
+    try:
+        # ascii is subset of UTF-8, this should be quite safe...
+        with open(KEYSFILE, "r", encoding='utf-8') as cfile:
+            user_keys = json.load(cfile)
 
+            if 'user_publickeys' not in user_keys:
+                raise ValueError('Missing required property "user_publickeys" in config file')
+
+            return user_keys["user_publickeys"]
+    except FileNotFoundError:
+        empty_userkeys = {
+                "user_publickeys": {
+                    "user_name": "user_ecdsa_public key"
+                    }
+                }
+        empty_userkeys_json = json.dumps(empty_userkeys)
+        with open(KEYSFILE, "w", encoding='utf-8') as nfile:
+            print('You seem be lacking the users key file, created example for you. Exiting')
+            json.dump(empty_userkeys_json, nfile)
+            raise EmptyUsersFile('Error')
+    return {}
 
 def check_database():
     """
@@ -398,9 +419,12 @@ def give_serverkey():
 if __name__ == "__main__":
     # Make sanity checks for the database
     check_database()
+    database_lock = threading.Lock()
 
     # Get the users public keys
-    user_publickeys = read_keys()
+    try:
+      user_publickeys = read_keys()
+
 
     # Start the data fetching backend process§
     fetch_thread = threading.Thread(target=get_the_data)