Introduce environment variable 'IOTTB_HOME' to represent the root of the iottb database tree.

code/iottb/__main__.py

@@ -1,9 +1,14 @@
 #!/usr/bin/env python3
 import argparse
+from os import environ
+from pathlib import Path
 
-from iottb.subcommands.capture import setup_capture_parser
+from iottb.logger import logger
 from iottb.subcommands.add_device import setup_init_device_root_parser
+from iottb.subcommands.capture import setup_capture_parser
 from iottb.utils.tcpdump_utils import list_interfaces
+from definitions import IOTTB_HOME_ABS, ReturnCodes
+
 
 ######################
 # Argparse setup
@@ -28,7 +33,37 @@ def setup_argparse():
     return root_parser
 
 
+def check_iottb_env():
+    # This makes the option '--root-dir' obsolescent # TODO How to streamline this?\
+    try:
+        iottb_home = environ['IOTTB_HOME']  # TODO WARN implicit declaration of env var name!
+    except KeyError:
+        logger.error(f"Environment variable 'IOTTB_HOME' is not set."
+                     f"Setting environment variable 'IOTTB_HOME' to '~/{IOTTB_HOME_ABS}'")
+        environ['IOTTB_HOME'] = IOTTB_HOME_ABS
+    finally:
+        if not Path(IOTTB_HOME_ABS).exists():
+            print(f'"{IOTTB_HOME_ABS}" does not exist.')
+            response = input('Do you want to create it now? [y/N]')
+            logger.debug(f'response: {response}')
+            if response.lower() != 'y':
+                logger.debug(f'Not creating "{environ['IOTTB_HOME']}"')
+                print('TODO')
+                print("Aborting execution...")
+                return ReturnCodes.ABORTED
+            else:
+                print(f'Creating "{environ['IOTTB_HOME']}"')
+                Path(IOTTB_HOME_ABS).mkdir(parents=True,
+                                           exist_ok=False)  # Should always work since in 'not exist' code path
+                return ReturnCodes.OK
+        logger.info(f'"{IOTTB_HOME_ABS}" exists.')
+        # TODO: Check that it is a valid iottb dir or can we say it is valid by definition if?
+        return ReturnCodes.OK
+
+
 def main():
+    if check_iottb_env() != ReturnCodes.OK:
+        exit(ReturnCodes.ABORTED)
     parser = setup_argparse()
     args = parser.parse_args()
     print(args)

code/iottb/definitions.py

@@ -1,6 +1,17 @@
 from datetime import datetime
 from enum import Flag, unique, global_enum
+from pathlib import Path
 
+
+''' 
+Defining IOTTB_HOME_ABS here implies that it be immutable.
+It is used here so that one could configure it. 
+But after its used in __man__ this cannot be relied upon.
+'''
+IOTTB_HOME_ABS = Path().home() / 'IOTTB.db'
+
+# TODO maybe wrap this into class to make it easier to pass along to different objects
+# But will need more refactoring
 DEVICE_METADATA_FILE = 'device_metadata.json'
 CAPTURE_METADATA_FILE = 'capture_metadata.json'
 TODAY_DATE_STRING = datetime.now().strftime('%d%b%Y').lower()  # TODO convert to function in utils or so
@@ -24,3 +35,7 @@ class ReturnCodes(Flag):
     FILE_ALREADY_EXISTS = 5
     INVALID_ARGUMENT = 6
     INVALID_ARGUMENT_VALUE = 7
+
+
+def iottb_home_abs():
+    return None