feat: Enhance chat streaming and tool call processing (#498)

* feat: Enhance chat streaming and tool call processing

- Added support for MongoDB checkpointer in the chat streaming workflow.
- Introduced functions to process tool call chunks and sanitize arguments.
- Improved event message creation with additional metadata.
- Enhanced error handling for JSON serialization in event messages.
- Updated the frontend to convert escaped characters in tool call arguments.
- Refactored the workflow input preparation and initial message processing.
- Added new dependencies for MongoDB integration and tool argument sanitization.

* fix: Update MongoDB checkpointer configuration to use LANGGRAPH_CHECKPOINT_DB_URL

* feat: Add support for Postgres checkpointing and update README with database recommendations

* feat: Implement checkpoint saver functionality and update MongoDB connection handling

* refactor: Improve code formatting and readability in app.py and json_utils.py

* refactor: Clean up commented code and improve formatting in server.py

* refactor: Remove unused imports and improve code organization in app.py

* refactor: Improve code organization and remove unnecessary comments in app.py

* chore: use langgraph-checkpoint-postgres==2.0.21 to avoid the JSON convert issue in the latest version, implement chat stream persistant with Postgres

* feat: add MongoDB and PostgreSQL support for LangGraph checkpointing, enhance environment variable handling

* fix: update comments for clarity on Windows event loop policy

* chore: remove empty code changes in MongoDB and PostgreSQL checkpoint tests

* chore: clean up unused imports and code in checkpoint-related files

* chore: remove empty code changes in test_checkpoint.py

* chore: remove empty code changes in test_checkpoint.py

* chore: remove empty code changes in test_checkpoint.py

* test: update status code assertions in MCP endpoint tests to allow for 403 responses

* test: update MCP endpoint tests to assert specific status codes and enable MCP server configuration

* chore: remove unnecessary environment variables from unittest workflow

* fix: invert condition for MCP server configuration check to raise 403 when disabled

* chore: remove pymongo from test dependencies in uv.lock

* chore:  optimize the _get_agent_name method

* test: enhance ChatStreamManager tests for PostgreSQL and MongoDB initialization

* test: add persistence tests for ChatStreamManager with PostgreSQL and MongoDB

* test: add unit tests for ChatStreamManager initialization with PostgreSQL and MongoDB

* test: enhance persistence tests for ChatStreamManager with PostgreSQL and MongoDB to verify message aggregation

* test: add unit tests for ChatStreamManager with PostgreSQL and MongoDB

* test: add unit tests for ChatStreamManager initialization with PostgreSQL and MongoDB

* test: add unit tests for ChatStreamManager initialization with PostgreSQL and MongoDB

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

src/config/configuration.py

@@ -13,6 +13,33 @@ from src.config.report_style import ReportStyle
 
 logger = logging.getLogger(__name__)
 
+_TRUTHY = {"1", "true", "yes", "y", "on"}
+
+
+def get_bool_env(name: str, default: bool = False) -> bool:
+    val = os.getenv(name)
+    if val is None:
+        return default
+    return str(val).strip().lower() in _TRUTHY
+
+
+def get_str_env(name: str, default: str = "") -> str:
+    val = os.getenv(name)
+    return default if val is None else str(val).strip()
+
+
+def get_int_env(name: str, default: int = 0) -> int:
+    val = os.getenv(name)
+    if val is None:
+        return default
+    try:
+        return int(val.strip())
+    except ValueError:
+        logger.warning(
+            f"Invalid integer value for {name}: {val}. Using default {default}."
+        )
+        return default
+
 
 def get_recursion_limit(default: int = 25) -> int:
     """Get the recursion limit from environment variable or use default.
@@ -23,23 +50,15 @@ def get_recursion_limit(default: int = 25) -> int:
     Returns:
         int: The recursion limit to use
     """
-    try:
-        env_value_str = os.getenv("AGENT_RECURSION_LIMIT", str(default))
-        parsed_limit = int(env_value_str)
+    env_value_str = get_str_env("AGENT_RECURSION_LIMIT", str(default))
+    parsed_limit = get_int_env("AGENT_RECURSION_LIMIT", default)
 
-        if parsed_limit > 0:
-            logger.info(f"Recursion limit set to: {parsed_limit}")
-            return parsed_limit
-        else:
-            logger.warning(
-                f"AGENT_RECURSION_LIMIT value '{env_value_str}' (parsed as {parsed_limit}) is not positive. "
-                f"Using default value {default}."
-            )
-            return default
-    except ValueError:
-        raw_env_value = os.getenv("AGENT_RECURSION_LIMIT")
+    if parsed_limit > 0:
+        logger.info(f"Recursion limit set to: {parsed_limit}")
+        return parsed_limit
+    else:
         logger.warning(
-            f"Invalid AGENT_RECURSION_LIMIT value: '{raw_env_value}'. "
+            f"AGENT_RECURSION_LIMIT value '{env_value_str}' (parsed as {parsed_limit}) is not positive. "
             f"Using default value {default}."
         )
         return default