Feature/consolidate cassandra config (#483)

* Cassandra consolidation of parameters

* New Cassandra configuration helper

* Implemented Cassanda config refactor

* New tests

trustgraph-base/trustgraph/base/cassandra_config.py

@@ -0,0 +1,144 @@
+"""
+Cassandra configuration utilities for standardized parameter handling.
+
+Provides consistent Cassandra configuration across all TrustGraph processors,
+including command-line arguments, environment variables, and defaults.
+"""
+
+import os
+import argparse
+from typing import Optional, Tuple, List, Any
+
+
+def get_cassandra_defaults() -> dict:
+    """
+    Get default Cassandra configuration values from environment variables or fallback defaults.
+    
+    Returns:
+        dict: Dictionary with 'host', 'username', and 'password' keys
+    """
+    return {
+        'host': os.getenv('CASSANDRA_HOST', 'cassandra'),
+        'username': os.getenv('CASSANDRA_USERNAME'),
+        'password': os.getenv('CASSANDRA_PASSWORD')
+    }
+
+
+def add_cassandra_args(parser: argparse.ArgumentParser) -> None:
+    """
+    Add standardized Cassandra configuration arguments to an argument parser.
+    
+    Shows environment variable values in help text when they are set.
+    Password values are never displayed for security.
+    
+    Args:
+        parser: ArgumentParser instance to add arguments to
+    """
+    defaults = get_cassandra_defaults()
+    
+    # Format help text with environment variable indication
+    host_help = f"Cassandra host list, comma-separated (default: {defaults['host']})"
+    if 'CASSANDRA_HOST' in os.environ:
+        host_help += " [from CASSANDRA_HOST]"
+    
+    username_help = "Cassandra username"
+    if defaults['username']:
+        username_help += f" (default: {defaults['username']})"
+        if 'CASSANDRA_USERNAME' in os.environ:
+            username_help += " [from CASSANDRA_USERNAME]"
+    
+    password_help = "Cassandra password"
+    if defaults['password']:
+        # Never show actual password value
+        password_help += " (default: <set>)"
+        if 'CASSANDRA_PASSWORD' in os.environ:
+            password_help += " [from CASSANDRA_PASSWORD]"
+    
+    parser.add_argument(
+        '--cassandra-host',
+        default=defaults['host'],
+        help=host_help
+    )
+    
+    parser.add_argument(
+        '--cassandra-username',
+        default=defaults['username'],
+        help=username_help
+    )
+    
+    parser.add_argument(
+        '--cassandra-password',
+        default=defaults['password'],
+        help=password_help
+    )
+
+
+def resolve_cassandra_config(
+    args: Optional[Any] = None,
+    host: Optional[str] = None,
+    username: Optional[str] = None,
+    password: Optional[str] = None
+) -> Tuple[List[str], Optional[str], Optional[str]]:
+    """
+    Resolve Cassandra configuration from various sources.
+    
+    Can accept either argparse args object or explicit parameters.
+    Converts host string to list format for Cassandra driver.
+    
+    Args:
+        args: Optional argparse namespace with cassandra_host, cassandra_username, cassandra_password
+        host: Optional explicit host parameter (overrides args)
+        username: Optional explicit username parameter (overrides args)
+        password: Optional explicit password parameter (overrides args)
+    
+    Returns:
+        tuple: (hosts_list, username, password)
+    """
+    # If args provided, extract values
+    if args is not None:
+        host = host or getattr(args, 'cassandra_host', None)
+        username = username or getattr(args, 'cassandra_username', None)
+        password = password or getattr(args, 'cassandra_password', None)
+    
+    # Apply defaults if still None
+    defaults = get_cassandra_defaults()
+    host = host or defaults['host']
+    username = username or defaults['username']
+    password = password or defaults['password']
+    
+    # Convert host string to list
+    if isinstance(host, str):
+        hosts = [h.strip() for h in host.split(',') if h.strip()]
+    else:
+        hosts = host
+    
+    return hosts, username, password
+
+
+def get_cassandra_config_from_params(params: dict) -> Tuple[List[str], Optional[str], Optional[str]]:
+    """
+    Extract and resolve Cassandra configuration from a parameters dictionary.
+    
+    Handles both old graph_* and new cassandra_* parameter names for backward compatibility.
+    
+    Args:
+        params: Dictionary of parameters that may contain Cassandra configuration
+    
+    Returns:
+        tuple: (hosts_list, username, password)
+    """
+    # Check for new parameter names first
+    host = params.get('cassandra_host')
+    username = params.get('cassandra_username')
+    password = params.get('cassandra_password')
+    
+    # Fall back to old graph_* names for backward compatibility
+    if not host:
+        host = params.get('graph_host')
+    if not username:
+        username = params.get('graph_username', params.get('cassandra_user'))
+    if not password:
+        password = params.get('graph_password')
+    
+    # Use resolve function to handle defaults and list conversion
+    return resolve_cassandra_config(host=host, username=username, password=password)