feat: add config file support with env var substitution

Author: mdesmet

src/datapilot/cli/main.py

@@ -1,21 +1,95 @@
+import json
+import os
+import re
+from pathlib import Path
+
 import click
+from dotenv import load_dotenv
 
 from datapilot.core.mcp_utils.mcp import mcp
 from datapilot.core.platforms.dbt.cli.cli import dbt
 
 
+def load_config_from_file():
+    """Load configuration from ~/.altimate/altimate.json if it exists."""
+    config_path = Path.home() / ".altimate" / "altimate.json"
+    
+    if not config_path.exists():
+        return {}
+    
+    try:
+        with open(config_path, 'r') as f:
+            config = json.load(f)
+        return config
+    except (json.JSONDecodeError, IOError) as e:
+        click.echo(f"Warning: Failed to load config from {config_path}: {e}", err=True)
+        return {}
+
+
+def substitute_env_vars(value):
+    """Replace ${env:ENV_VARIABLE} patterns with actual environment variable values."""
+    if not isinstance(value, str):
+        return value
+    
+    # Pattern to match ${env:VARIABLE_NAME}
+    pattern = r'\$\{env:([^}]+)\}'
+    
+    def replacer(match):
+        env_var = match.group(1)
+        return os.environ.get(env_var, match.group(0))
+    
+    return re.sub(pattern, replacer, value)
+
+
+def process_config(config):
+    """Process configuration dictionary to substitute environment variables."""
+    processed = {}
+    for key, value in config.items():
+        processed[key] = substitute_env_vars(value)
+    return processed
+
+
 @click.group()
 @click.option("--token", required=False, help="Your API token for authentication.")
 @click.option("--instance-name", required=False, help="Your tenant ID.")
 @click.option("--backend-url", required=False, help="Altimate's Backend URL", default="https://api.myaltimate.com")
 @click.pass_context
 def datapilot(ctx, token, instance_name, backend_url):
     """Altimate CLI for DBT project management."""
-    # Store common options in context
+    # Load .env file from current directory if it exists
+    load_dotenv()
+    
+    # Load configuration from file
+    file_config = load_config_from_file()
+    file_config = process_config(file_config)
+    
+    # Map config file keys to CLI option names
+    config_mapping = {
+        'altimateApiKey': 'token',
+        'altimateInstanceName': 'instance_name',
+        'altimateUrl': 'backend_url'
+    }
+    
+    # Store common options in context, with CLI args taking precedence
     ctx.ensure_object(dict)
-    ctx.obj['token'] = token
-    ctx.obj['instance_name'] = instance_name
-    ctx.obj['backend_url'] = backend_url
+    
+    # Apply file config first
+    for file_key, cli_key in config_mapping.items():
+        if file_key in file_config:
+            ctx.obj[cli_key] = file_config[file_key]
+    
+    # Override with CLI arguments if provided
+    if token is not None:
+        ctx.obj['token'] = token
+    if instance_name is not None:
+        ctx.obj['instance_name'] = instance_name
+    if backend_url != "https://api.myaltimate.com":  # Only override if not default
+        ctx.obj['backend_url'] = backend_url
+    
+    # Set defaults if nothing was provided
+    ctx.obj.setdefault('token', None)
+    ctx.obj.setdefault('instance_name', None)
+    ctx.obj.setdefault('backend_url', 'https://api.myaltimate.com')
 
 
 datapilot.add_command(dbt)