Allow oneshot commands from the terminal. (#208)

* Allow oneshot commands from the terminal.

This patch allows the use of mreg-cli without interaction, ala:

`mreg-cli host info foo`

This will then feed the command `host info foo` to the cli and then exit.

Also adds an option to force token only login. Good for scripts. :)

mreg_cli/main.py

@@ -112,6 +112,18 @@ def main():
         metavar="SOURCE",
     )
 
+    output_args.add_argument(
+        "--token-only",
+        dest="token_only",
+        action="store_true",
+        default=False,
+        help="Only attempt token login, this will avoid interactive prompts.",
+    )
+
+    output_args.add_argument(
+        "command", metavar="command", nargs="*", help="Oneshot command to issue to the cli."
+    )
+
     args = parser.parse_args()
     setup_logging(args.verbosity)
     logger.debug(f"args: {args}")
@@ -135,7 +147,10 @@ def main():
         return
 
     try:
-        try_token_or_login(config.get("user"), config.get("url"))
+        try_token_or_login(
+            config.get("user"), config.get("url"), fail_without_token=args.token_only
+        )
+
     except (EOFError, KeyboardInterrupt, LoginFailedError) as e:
         print(e)
         raise SystemExit() from None
@@ -171,6 +186,16 @@ def get_prompt_message():
             cli.process_command_line(command)
         return
 
+    # Check if we got a oneshot command. If so, execute it and exit.
+    if args.command:
+        cmd = " ".join(args.command)
+        try:
+            cli.process_command_line(cmd)
+        except ValueError as e:
+            print(e)
+
+        raise SystemExit() from None
+
     # The app runs in an infinite loop and is expected to exit using sys.exit()
     while True:
         try:

mreg_cli/utilities/api.py

@@ -52,7 +52,7 @@ def set_file_permissions(f: str, mode: int) -> None:
         pass
 
 
-def try_token_or_login(user: str, url: str) -> None:
+def try_token_or_login(user: str, url: str, fail_without_token: bool = False) -> None:
     """Check for a valid token or interactively log in to MREG.
 
     Exits on connection failure.
@@ -90,6 +90,8 @@ def try_token_or_login(user: str, url: str) -> None:
         error(f"Could not connect to {url}")
 
     if ret.status_code == 401:
+        if fail_without_token:
+            raise SystemExit("Token only login failed.")
         prompt_for_password_and_login(user, url, catch_exception=False)