Improves cli

- Improves modularity
- Adds missing exceptions
- Adds docstrings
- Simplifies some method names

apps/cli/pisa_cli.py

@@ -13,13 +13,12 @@ from apps.cli import config, LOG_PREFIX
 from apps.cli.help import help_add_appointment, help_get_appointment
 from apps.cli.blob import Blob
 
+from common import constants
 from common.logger import Logger
 from common.appointment import Appointment
 from common.cryptographer import Cryptographer
 from common.tools import check_sha256_hex_format, check_locator_format, compute_locator
 
-
-HTTP_OK = 200
 logger = Logger(actor="Client", log_name_prefix=LOG_PREFIX)
 
 
@@ -47,39 +46,81 @@ def generate_dummy_appointment():
     logger.info("\nData stored in dummy_appointment_data.json")
 
 
-# Loads and returns Pisa keys from disk
+def load_keys(pisa_pk_path, cli_sk_path, cli_pk_path):
-def load_key_file_data(file_name):
+    """
-    try:
+    Loads all the keys required so sign, send, and verify the appointment.
-        with open(file_name, "rb") as key_file:
-            key = key_file.read()
-        return key
 
-    except FileNotFoundError as e:
+    Args:
-        logger.error("Client's key file not found. Please check your settings")
+        pisa_pk_path (:obj:`str`): path to the PISA public key file.
-        raise e
+        cli_sk_path (:obj:`str`): path to the client private key file.
+        cli_pk_path (:obj:`str`): path to the client public key file.
 
-    except IOError as e:
+    Returns:
-        logger.error("I/O error({}): {}".format(e.errno, e.strerror))
+        :obj:`tuple` or ``None``: a three item tuple containing a pisa_pk object, cli_sk object and the cli_sk_der
-        raise e
+        encoded key if all keys can be loaded. ``None`` otherwise.
+    """
 
+    pisa_pk_der = Cryptographer.load_key_file(pisa_pk_path)
+    pisa_pk = Cryptographer.load_public_key_der(pisa_pk_der)
 
-# Makes sure that the folder APPOINTMENTS_FOLDER_NAME exists, then saves the appointment and signature in it.
+    if pisa_pk is None:
-def save_signed_appointment(appointment, signature):
+        logger.error("PISA's public key file not found. Please check your settings")
-    # Create the appointments directory if it doesn't already exist
+        return None
-    os.makedirs(config.get("APPOINTMENTS_FOLDER_NAME"), exist_ok=True)
 
-    timestamp = int(time.time())
+    cli_sk_der = Cryptographer.load_key_file(cli_sk_path)
-    locator = appointment["locator"]
+    cli_sk = Cryptographer.load_private_key_der(cli_sk_der)
-    uuid = uuid4().hex  # prevent filename collisions
 
-    filename = "{}/appointment-{}-{}-{}.json".format(config.get("APPOINTMENTS_FOLDER_NAME"), timestamp, locator, uuid)
+    if cli_sk is None:
-    data = {"appointment": appointment, "signature": signature}
+        logger.error("Client's private key file not found. Please check your settings")
+        return None
 
-    with open(filename, "w") as f:
+    cli_pk_der = Cryptographer.load_key_file(cli_pk_path)
-        json.dump(data, f)
+
+    if cli_pk_der is None:
+        logger.error("Client's public key file not found. Please check your settings")
+        return None
+
+    return pisa_pk, cli_sk, cli_pk_der
 
 
 def add_appointment(args):
+    """
+    Manages the add_appointment command, from argument parsing, trough sending the appointment to the tower, until
+    saving the appointment receipt.
+
+    The life cycle of the function is as follows:
+        - Load the add_appointment arguments
+        - Check that the given commitment_txid is correct (proper format and not missing)
+        - Check that the transaction is correct (not missing)
+        - Create the appointment locator and encrypted blob from the commitment_txid and the penalty_tx
+        - Load the client private key and sign the appointment
+        - Send the appointment to the tower
+        - Wait for the response
+        - Check the tower's response and signature
+        - Store the receipt (appointment + signature) on disk
+
+    If any of the above-mentioned steps fails, the method returns false, otherwise it returns true.
+
+    Args:
+        args (:obj:`list`): a list of arguments to pass to ``parse_add_appointment_args``. Must contain a json encoded
+            appointment, or the file option and the path to a file containing a json encoded appointment.
+
+    Returns:
+        :obj:`bool`: True if the appointment is accepted by the tower and the receipt is properly stored, false if any
+        error occurs during the process.
+    """
+
+    pisa_pk, cli_sk, cli_pk_der = load_keys(
+        config.get("PISA_PUBLIC_KEY"), config.get("CLI_PRIVATE_KEY"), config.get("CLI_PUBLIC_KEY")
+    )
+
+    try:
+        hex_pk_der = binascii.hexlify(cli_pk_der)
+
+    except binascii.Error as e:
+        logger.error("Could not successfully encode public key as hex", error=str(e))
+        return False
+
     # Get appointment data from user.
     appointment_data = parse_add_appointment_args(args)
 
@@ -105,17 +146,16 @@ def add_appointment(args):
         return False
 
     appointment = Appointment.from_dict(appointment_data)
+    signature = Cryptographer.sign(appointment.serialize(), cli_sk)
 
-    signature = get_appointment_signature(appointment)
+    if not (appointment and signature):
-    hex_pk_der = get_pk()
-
-    if not (appointment and signature and hex_pk_der):
         return False
 
     data = {"appointment": appointment.to_dict(), "signature": signature, "public_key": hex_pk_der.decode("utf-8")}
 
     # Send appointment to the server.
-    response_json = post_data_to_add_appointment_endpoint(data)
+    server_response = post_appointment(data)
+    response_json = process_post_appointment_response(server_response)
 
     if response_json is None:
         return False
@@ -126,27 +166,29 @@ def add_appointment(args):
         logger.error("The response does not contain the signature of the appointment")
         return False
 
-    valid = check_signature(signature, appointment)
+    if not Cryptographer.verify(appointment.serialize(), signature, pisa_pk):
-
-    if not valid:
         logger.error("The returned appointment's signature is invalid")
         return False
 
-    logger.info("Appointment accepted and signed by Pisa")
+    logger.info("Appointment accepted and signed by PISA")
-    # all good, store appointment and signature
-    try:
-        save_signed_appointment(appointment.to_dict(), signature)
 
-    except OSError as e:
+    # All good, store appointment and signature
-        logger.error("There was an error while saving the appointment", error=e)
+    return save_appointment_receipt(appointment.to_dict(), signature)
-        return False
-
-    return True
 
 
-# Parse arguments passed to add_appointment and handle them accordingly.
-# Returns appointment data.
 def parse_add_appointment_args(args):
+    """
+    Parses the arguments of the add_appointment command.
+
+    Args:
+        args (:obj:`list`): a list of arguments to pass to ``parse_add_appointment_args``. Must contain a json encoded
+            appointment, or the file option and the path to a file containing a json encoded appointment.
+
+    Returns:
+        :obj:`dict` or :obj:`None`: A dictionary containing the appointment data if it can be loaded. ``None``
+        otherwise.
+    """
+
     use_help = "Use 'help add_appointment' for help of how to use the command"
 
     if not args:
@@ -182,79 +224,117 @@ def parse_add_appointment_args(args):
     return appointment_data
 
 
-# Sends appointment data to add_appointment endpoint to be processed by the server.
+def post_appointment(data):
-def post_data_to_add_appointment_endpoint(data):
+    """
+    Sends appointment data to add_appointment endpoint to be processed by the tower.
+
+    Args:
+        data (:obj:`dict`): a dictionary containing three fields: an appointment, the client-side signature, and the
+            der-encoded client public key.
+
+    Returns:
+        :obj:`dict` or ``None``: a json-encoded dictionary with the server response if the data can be posted.
+        None otherwise.
+    """
+
     logger.info("Sending appointment to PISA")
 
     try:
         add_appointment_endpoint = "http://{}:{}".format(pisa_api_server, pisa_api_port)
-        r = requests.post(url=add_appointment_endpoint, json=json.dumps(data), timeout=5)
+        return requests.post(url=add_appointment_endpoint, json=json.dumps(data), timeout=5)
 
-        response_json = r.json()
+    except ConnectTimeout:
+        logger.error("Can't connect to PISA API. Connection timeout")
+        return None
+
+    except ConnectionError:
+        logger.error("Can't connect to PISA API. Server cannot be reached")
+        return None
+
+
+def process_post_appointment_response(response):
+    """
+    Processes the server response to an add_appointment request.
+
+    Args:
+        response (:obj:`requests.models.Response`): a ``Response` object obtained from the sent request.
+
+    Returns:
+        :obj:`dict` or :obj:`None`: a dictionary containing the tower's response data if it can be properly parsed and
+        the response type is ``HTTP_OK``. ``None`` otherwise.
+    """
+
+    try:
+        response_json = response.json()
 
     except json.JSONDecodeError:
         logger.error("The response was not valid JSON")
         return None
 
-    except ConnectTimeout:
+    if response.status_code != constants.HTTP_OK:
-        logger.error("Can't connect to pisa API. Connection timeout")
-        return None
-
-    except ConnectionError:
-        logger.error("Can't connect to pisa API. Server cannot be reached")
-        return None
-
-    if r.status_code != HTTP_OK:
         if "error" not in response_json:
-            logger.error("The server returned an error status code but no error description", status_code=r.status_code)
+            logger.error(
+                "The server returned an error status code but no error description", status_code=response.status_code
+            )
         else:
             error = response_json["error"]
             logger.error(
                 "The server returned an error status code with an error description",
-                status_code=r.status_code,
+                status_code=response.status_code,
                 description=error,
             )
         return None
 
-    if "signature" not in response_json:
-        logger.error("The response does not contain the signature of the appointment")
-        return None
-
     return response_json
 
 
-# Verify that the signature returned from the watchtower is valid.
+def save_appointment_receipt(appointment, signature):
-def check_signature(signature, appointment):
+    """
+    Saves an appointment receipt to disk. A receipt consists in an appointment and a signature from the tower.
+
+    Args:
+        appointment (:obj:`Appointment <common.appointment.Appointment>`): the appointment to be saved on disk.
+        signature (:obj:`str`): the signature of the appointment performed by the tower.
+
+    Returns:
+        :obj:`bool`: True if the appointment if properly saved, false otherwise.
+
+    Raises:
+        IOError: if an error occurs whilst writing the file on disk.
+    """
+
+    # Create the appointments directory if it doesn't already exist
+    os.makedirs(config.get("APPOINTMENTS_FOLDER_NAME"), exist_ok=True)
+
+    timestamp = int(time.time())
+    locator = appointment["locator"]
+    uuid = uuid4().hex  # prevent filename collisions
+
+    filename = "{}/appointment-{}-{}-{}.json".format(config.get("APPOINTMENTS_FOLDER_NAME"), timestamp, locator, uuid)
+    data = {"appointment": appointment, "signature": signature}
+
     try:
-        pisa_pk_der = load_key_file_data(config.get("PISA_PUBLIC_KEY"))
+        with open(filename, "w") as f:
-        pisa_pk = Cryptographer.load_public_key_der(pisa_pk_der)
+            json.dump(data, f)
-
+            return True
-        if pisa_pk is None:
-            logger.error("Failed to deserialize the public key. It might be in an unsupported format")
-            return False
-
-        return Cryptographer.verify(appointment.serialize(), signature, pisa_pk)
-
-    except FileNotFoundError:
-        logger.error("Pisa's public key file not found. Please check your settings")
-        return False
 
     except IOError as e:
-        logger.error("I/O error", errno=e.errno, error=e.strerror)
+        logger.error("There was an error while saving the appointment", error=e)
         return False
 
 
-def get_appointment(args):
+def get_appointment(locator):
-    if not args:
+    """
-        logger.error("No arguments were given")
+    Gets information about an appointment from the tower.
-        return None
 
-    arg_opt = args.pop(0)
+    Args:
+        locator (:obj:`str`): the appointment locator used to identify it.
+
+    Returns:
+        :obj:`dict` or :obj:`None`: a dictionary containing thew appointment data if the locator is valid and the tower
+        responds. ``None`` otherwise.
+    """
 
-    if arg_opt in ["-h", "--help"]:
-        sys.exit(help_get_appointment())
-    else:
-        locator = arg_opt
     valid_locator = check_locator_format(locator)
 
     if not valid_locator:
@@ -266,60 +346,17 @@ def get_appointment(args):
 
     try:
         r = requests.get(url=get_appointment_endpoint + parameters, timeout=5)
-        logger.info("Appointment response returned from server: {}".format(r.json()))
         return r.json()
 
     except ConnectTimeout:
-        logger.error("Can't connect to pisa API. Connection timeout")
+        logger.error("Can't connect to PISA API. Connection timeout")
         return None
 
     except ConnectionError:
-        logger.error("Can't connect to pisa API. Server cannot be reached")
+        logger.error("Can't connect to PISA API. Server cannot be reached")
         return None
 
 
-def get_appointment_signature(appointment):
-    try:
-        sk_der = load_key_file_data(config.get("CLI_PRIVATE_KEY"))
-        cli_sk = Cryptographer.load_private_key_der(sk_der)
-
-        signature = Cryptographer.sign(appointment.serialize(), cli_sk)
-
-        return signature
-
-    except ValueError:
-        logger.error("Failed to deserialize the public key. It might be in an unsupported format")
-        return False
-
-    except FileNotFoundError:
-        logger.error("Client's private key file not found. Please check your settings")
-        return False
-
-    except IOError as e:
-        logger.error("I/O error", errno=e.errno, error=e.strerror)
-        return False
-
-
-def get_pk():
-    try:
-        cli_pk_der = load_key_file_data(config.get("CLI_PUBLIC_KEY"))
-        hex_pk_der = binascii.hexlify(cli_pk_der)
-
-        return hex_pk_der
-
-    except FileNotFoundError:
-        logger.error("Client's public key file not found. Please check your settings")
-        return False
-
-    except IOError as e:
-        logger.error("I/O error", errno=e.errno, error=e.strerror)
-        return False
-
-    except binascii.Error as e:
-        logger.error("Could not successfully encode public key as hex: ", e)
-        return False
-
-
 def show_usage():
     return (
         "USAGE: "
@@ -332,7 +369,7 @@ def show_usage():
         "\n\t-s, --server \tAPI server where to send the requests. Defaults to btc.pisa.watch (modifiable in "
         "__init__.py)"
         "\n\t-p, --port \tAPI port where to send the requests. Defaults to 9814 (modifiable in __init__.py)"
-        "\n\t-d, --debug \tshows debug information and stores it in pisa.log"
+        "\n\t-d, --debug \tshows debug information and stores it in pisa_cli.log"
         "\n\t-h --help \tshows this message."
     )
 
@@ -366,7 +403,18 @@ if __name__ == "__main__":
                     add_appointment(args)
 
                 elif command == "get_appointment":
-                    get_appointment(args)
+                    if not args:
+                        logger.error("No arguments were given")
+
+                    else:
+                        arg_opt = args.pop(0)
+
+                        if arg_opt in ["-h", "--help"]:
+                            sys.exit(help_get_appointment())
+
+                        appointment_data = get_appointment(arg_opt)
+                        if appointment_data:
+                            print(appointment_data)
 
                 elif command == "help":
                     if args: