google-calendar: Call get-google-credentials script internally.

The auth tokens expire every hour. So, the google-calendar script would
stop functioning one hour after start, if it only loads from the token
file.
The get-google-credential script needs to be called directly from the
google-calendar script, without the user needing to run that as a
separate command.

The get-google-credentials script is not a module.
And it uses hyphens in its name, hence it cannot be directly imported
into google-calendar.
To avoid renaming files, and smoothly pass in arguments, runpy is used.

Though google-calendar script is currently the only google service
integration that uses get-google-credentials, the script is not merged
with the google-calendar script, to keep the logic separate, and easy
to expand.

The get-google-credentials script can no longer be run directly, as the
get_credentials() arguments do not have any default values, with the
constants deleted, to avoid redundancy with the google-calendar script.

Updated the function docstrings, usage help and error messages.

Author: Niloth-p

zulip/integrations/google/get-google-credentials

@@ -2,23 +2,20 @@
 import logging
 import os
 import sys
+from typing import List
 
 from google.auth.transport.requests import Request
 from google.oauth2.credentials import Credentials
 from google_auth_oauthlib.flow import InstalledAppFlow
 
-SCOPES = ["https://www.googleapis.com/auth/calendar.events.readonly"]
-# File containing user's access and refresh tokens for Google application requests.
-# If it does not exist, e.g., first run, it is generated on user authorization.
-TOKENS_FILE = "google-tokens.json"
 # The client secret file identifies the application requesting the client's data,
 # and is required for the OAuth flow to fetch the tokens.
 # It needs to be downloaded from Google, by the user.
 CLIENT_SECRET_FILE = "client_secret.json"  # noqa: S105
 HOME_DIR = os.path.expanduser("~")
 
 
-def get_credentials() -> Credentials:
+def get_credentials(tokens_path: str, scopes: List[str]) -> Credentials:
     """
     Writes google tokens to a json file, using the client secret file (for the OAuth flow),
     and the refresh token.
@@ -33,12 +30,9 @@ def get_credentials() -> Credentials:
 
     The fetched tokens are written to storage in a json file, for reference by other scripts.
     """
-
     creds = None
-    tokens_path = os.path.join(HOME_DIR, TOKENS_FILE)
-
     if os.path.exists(tokens_path):
-        creds = Credentials.from_authorized_user_file(tokens_path, SCOPES)
+        creds = Credentials.from_authorized_user_file(tokens_path, scopes)
     if not creds or not creds.valid:
         if creds and creds.expired and creds.refresh_token:
             creds.refresh(Request())
@@ -50,11 +44,8 @@ def get_credentials() -> Credentials:
                     client_secret_path,
                 )
                 sys.exit(1)
-            flow = InstalledAppFlow.from_client_secrets_file(client_secret_path, SCOPES)
+            flow = InstalledAppFlow.from_client_secrets_file(client_secret_path, scopes)
             creds = flow.run_local_server(port=0)
         with open(tokens_path, "w") as token:
             token.write(creds.to_json())
     return creds
-
-
-get_credentials()

zulip/integrations/google/google-calendar

@@ -4,6 +4,7 @@ import datetime
 import itertools
 import logging
 import os
+import runpy
 import sys
 import time
 from typing import List, Optional, Set, Tuple
@@ -34,8 +35,6 @@ usage = r"""google-calendar --user EMAIL [--interval MINUTES] [--calendar CALEND
 
     Specify your Zulip API credentials and server in a ~/.zuliprc file, or using the options.
 
-    Before running this integration, make sure you download the client secret file from Google, and run the get-google-credentials script to give Zulip read access to your Google Calendar.
-
     This integration should be run on your local machine, as your API key is accessible to local users through the command line.
 
     For more information, see https://zulip.com/integrations/doc/google-calendar.
@@ -78,23 +77,17 @@ if options.verbose:
 
 
 def get_credentials() -> Credentials:
-    """Gets valid user credentials from storage.
-
-    If nothing has been stored, or if the stored credentials are invalid,
-    an exception is thrown and the user is informed to run the script in this directory to get
-    credentials.
+    """Fetches credentials using the get-google-credentials script.
 
-    Returns:
-        Credentials, the obtained credential.
+    Needs to call get-google-credentials everytime, because the auth token expires every hour,
+    needing to be refreshed using the refresh token.
     """
     try:
         tokens_path = os.path.join(HOME_DIR, TOKENS_FILE)
-        return Credentials.from_authorized_user_file(tokens_path, SCOPES)
-    except ValueError:
-        logging.exception("Error while trying to open the %s file.", TOKENS_FILE)
-        sys.exit(1)
-    except OSError:
-        logging.error("Run the get-google-credentials script from this directory first.")
+        fetch_creds = runpy.run_path("./get-google-credentials")["get_credentials"]
+        return fetch_creds(tokens_path, SCOPES)
+    except Exception:
+        logging.exception("Error getting google credentials")
         sys.exit(1)