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Enhanced Logging

Issue: #218 Status: โœ… Implemented Version: 1.0.0

RAG Modulo implements an enhanced logging system with structured context tracking, request correlation, and performance monitoring. Based on patterns from IBM mcp-context-forge.

Overview

The enhanced logging system provides:

  • Dual Output Formats: JSON for production/monitoring, text for development
  • Context Tracking: Automatic request correlation and entity tracking
  • Pipeline Stage Tracking: Track operations through each RAG pipeline stage
  • Performance Monitoring: Automatic timing for all operations
  • In-Memory Storage: Queryable log buffer for debugging and admin UI
  • Zero Performance Impact: Async logging with buffering

Architecture

Core Components

backend/core/
โ”œโ”€โ”€ logging_context.py        # Context management and propagation
โ”œโ”€โ”€ log_storage_service.py    # In-memory log storage with indexing
โ”œโ”€โ”€ enhanced_logging.py       # Main LoggingService orchestrator
โ””โ”€โ”€ enhanced_logging_example.py  # Integration examples

1. Context Management (logging_context.py)

Provides ContextVar-based async context propagation:

  • LogContext: Dataclass holding request/entity context
  • log_operation(): Context manager for operation tracking with timing
  • pipeline_stage_context(): Context manager for pipeline stage tracking
  • request_context(): Request-level context setup
  • PipelineStage: Constants for standard pipeline stages

2. Log Storage (log_storage_service.py)

In-memory circular buffer with entity indexing:

  • LogEntry: Dataclass for log entries with entity context
  • LogStorageService: Circular buffer (configurable MB limit)
  • Entity indexing: collection_id, user_id, request_id, pipeline_stage
  • Filtering, pagination, real-time streaming
  • Usage statistics

3. Logging Service (enhanced_logging.py)

Main orchestrator for structured logging:

  • LoggingService: Manages formatters, handlers, and storage
  • Dual formatters: JSON and text
  • StorageHandler: Custom handler for log capture
  • Integration with existing logging_utils.py for backward compatibility

Configuration

Environment Variables

Add to your .env file:

# Logging configuration
LOG_LEVEL=INFO                    # DEBUG, INFO, WARNING, ERROR, CRITICAL
LOG_FORMAT=text                   # text (dev) or json (prod)
LOG_TO_FILE=true
LOG_FILE=rag_modulo.log
LOG_FOLDER=logs
LOG_ROTATION_ENABLED=true
LOG_MAX_SIZE_MB=10
LOG_BACKUP_COUNT=5

# Log storage (in-memory)
LOG_STORAGE_ENABLED=true
LOG_BUFFER_SIZE_MB=5

Configuration Class

Settings are defined in backend/core/config.py:

class Settings(BaseSettings):
    log_level: str = "INFO"
    log_format: str = "text"  # or "json"
    log_to_file: bool = True
    log_file: str = "rag_modulo.log"
    log_folder: str | None = "logs"
    log_rotation_enabled: bool = True
    log_max_size_mb: int = 10
    log_backup_count: int = 5
    log_filemode: str = "a"

    # Log storage
    log_storage_enabled: bool = True
    log_buffer_size_mb: int = 5

Usage

Basic Usage in Services

from core.enhanced_logging import get_logger
from core.logging_context import log_operation, pipeline_stage_context, PipelineStage

logger = get_logger(__name__)

async def search(self, search_input: SearchInput) -> SearchOutput:
    # Wrap entire operation for automatic timing and context
    with log_operation(
        logger,
        "search_documents",
        entity_type="collection",
        entity_id=str(search_input.collection_id),
        user_id=str(search_input.user_id),
        query=search_input.question  # Additional metadata
    ):
        # Each pipeline stage tracked separately
        with pipeline_stage_context(PipelineStage.QUERY_VALIDATION):
            validate_search_input(search_input)

        with pipeline_stage_context(PipelineStage.QUERY_REWRITING):
            rewritten = await self.rewrite_query(search_input.question)
            logger.info("Query rewritten", extra={
                "original": search_input.question,
                "rewritten": rewritten
            })

        with pipeline_stage_context(PipelineStage.VECTOR_SEARCH):
            results = await self.vector_search(rewritten)
            logger.info("Vector search completed", extra={
                "result_count": len(results),
                "top_score": results[0].score if results else 0
            })

        return search_output

Chain of Thought Reasoning

async def chain_of_thought_search(
    self, collection_id: UUID, user_id: UUID, complex_query: str
) -> dict:
    with log_operation(
        logger,
        "chain_of_thought_reasoning",
        entity_type="collection",
        entity_id=str(collection_id),
        user_id=str(user_id),
    ):
        with pipeline_stage_context(PipelineStage.COT_QUESTION_DECOMPOSITION):
            sub_questions = await decompose_question(complex_query)
            logger.info("Question decomposed", extra={
                "sub_question_count": len(sub_questions),
                "sub_questions": sub_questions
            })

        # Process each sub-question
        for i, sub_q in enumerate(sub_questions):
            with pipeline_stage_context(PipelineStage.COT_REASONING):
                logger.info(f"Processing sub-question {i+1}/{len(sub_questions)}")
                answer = await self.search(collection_id, user_id, sub_q)

        with pipeline_stage_context(PipelineStage.COT_ANSWER_SYNTHESIS):
            final_answer = await synthesize_answers(sub_answers)
            logger.info("Answers synthesized")

        return final_answer

Error Handling

Errors are automatically logged with full context:

try:
    with log_operation(logger, "risky_operation", "collection", coll_id):
        # Operation code
        raise ValueError("Something went wrong")
except ValueError as e:
    # Error automatically logged with:
    # - Full context (request_id, entity, operation)
    # - Timing information
    # - Stack trace
    logger.error("Operation failed, implementing fallback")

Batch Processing

async def batch_process_documents(
    self, document_ids: list[str], collection_id: UUID
) -> list[dict]:
    with log_operation(
        logger,
        "batch_document_processing",
        entity_type="collection",
        entity_id=str(collection_id),
        document_count=len(document_ids)
    ):
        for i, doc_id in enumerate(document_ids):
            # Log progress periodically
            if i % 10 == 0:
                logger.info(f"Progress: {i}/{len(document_ids)}", extra={
                    "progress_percent": round((i / len(document_ids)) * 100, 1)
                })

            result = await process_document(doc_id)

        logger.info("Batch processing completed", extra={
            "total_documents": len(document_ids),
            "successful": len(results)
        })

Log Output Formats

Text Format (Development)

Human-readable format for local development:

[2025-10-22T10:30:45] INFO     rag.search: Starting search_documents [req_id=req_abc123, collection=coll_456, user=user_xyz]
[2025-10-22T10:30:45] INFO     rag.search: Query rewritten [stage=query_rewriting] | original=What is AI?, rewritten=artificial intelligence machine learning
[2025-10-22T10:30:45] INFO     rag.search: Vector search completed [stage=vector_search] | result_count=5, top_score=0.95
[2025-10-22T10:30:45] INFO     rag.search: Completed search_documents (took 234.56ms)

JSON Format (Production)

Structured format for monitoring tools (ELK, Splunk, CloudWatch):

{
  "timestamp": "2025-10-22T10:30:45.123Z",
  "level": "info",
  "logger": "rag.search",
  "message": "Query rewritten",
  "context": {
    "request_id": "req_abc123",
    "user_id": "user_xyz",
    "collection_id": "coll_456",
    "operation": "search_documents",
    "pipeline_stage": "query_rewriting"
  },
  "original": "What is AI?",
  "rewritten": "artificial intelligence machine learning",
  "execution_time_ms": 45.2
}

Pipeline Stages

Standard pipeline stage constants defined in PipelineStage class:

Query Processing

  • QUERY_VALIDATION - Input validation
  • QUERY_REWRITING - Query rewriting and expansion
  • QUERY_EXPANSION - Query term expansion
  • QUERY_DECOMPOSITION - Complex query decomposition

Embedding

  • EMBEDDING_GENERATION - Embedding vector generation
  • EMBEDDING_BATCHING - Batch embedding processing

Retrieval

  • VECTOR_SEARCH - Vector similarity search
  • KEYWORD_SEARCH - Keyword-based search
  • HYBRID_SEARCH - Hybrid vector + keyword search
  • DOCUMENT_RETRIEVAL - Document fetching
  • METADATA_GENERATION - Metadata extraction

Reranking

  • RERANKING - Result reranking
  • RELEVANCE_SCORING - Relevance score calculation

Generation

  • PROMPT_CONSTRUCTION - LLM prompt building
  • LLM_GENERATION - LLM inference
  • ANSWER_PROCESSING - Answer post-processing
  • SOURCE_ATTRIBUTION - Source citation generation

Chain of Thought

  • COT_REASONING - CoT reasoning step
  • COT_QUESTION_DECOMPOSITION - Question breakdown
  • COT_ANSWER_SYNTHESIS - Answer synthesis

Document Processing

  • DOCUMENT_PARSING - Document parsing
  • DOCUMENT_CHUNKING - Document chunking
  • DOCUMENT_INDEXING - Vector indexing

Collection Management

  • COLLECTION_CREATION - Collection creation
  • COLLECTION_VALIDATION - Collection validation
  • COLLECTION_DELETION - Collection deletion

API Reference

Context Management

log_operation(logger, operation, entity_type, entity_id, user_id=None, **metadata)

Context manager for tracking an operation with automatic timing.

Parameters: - logger: Logger instance - operation: Operation name (e.g., "search_documents") - entity_type: Entity type ("collection", "user", "pipeline", "document") - entity_id: Entity ID - user_id: Optional user ID - **metadata: Additional metadata

Example:

with log_operation(logger, "search", "collection", "abc123", user_id="user456"):
    # Operation code
    pass

pipeline_stage_context(stage)

Context manager for tracking pipeline stage transitions.

Parameters: - stage: Pipeline stage name (use PipelineStage constants)

Example:

with pipeline_stage_context(PipelineStage.QUERY_REWRITING):
    # Query rewriting code
    pass

request_context(request_id=None, user_id=None, **metadata)

Context manager for setting request-level context.

Parameters: - request_id: Request correlation ID (auto-generated if not provided) - user_id: User ID - **metadata: Additional request metadata

Example:

with request_context(user_id="user123", collection_id="coll456"):
    # Request handling code
    pass

Log Storage Service

LogStorageService.get_logs()

Query stored logs with filtering and pagination.

Parameters: - entity_type: Filter by entity type - entity_id: Filter by entity ID - level: Minimum log level - start_time: Start of time range - end_time: End of time range - request_id: Filter by request ID - pipeline_stage: Filter by pipeline stage - search: Search in message text - limit: Maximum number of results (default: 100) - offset: Number of results to skip (default: 0) - order: Sort order ("asc" or "desc", default: "desc")

Returns: List of log entry dictionaries

Example:

# Get logs for specific collection
logs = await storage.get_logs(
    entity_type="collection",
    entity_id="coll_123",
    level=LogLevel.INFO,
    limit=50
)

# Get logs for specific request
logs = await storage.get_logs(request_id="req_abc123")

# Get logs for pipeline stage
logs = await storage.get_logs(pipeline_stage="vector_search")

LogStorageService.get_stats()

Get storage statistics.

Returns: Dictionary with statistics: - total_logs: Total number of logs in buffer - buffer_size_bytes: Current buffer size in bytes - buffer_size_mb: Current buffer size in MB - max_size_mb: Maximum buffer size - usage_percent: Buffer usage percentage - unique_entities: Number of unique entities - unique_requests: Number of unique requests - unique_pipeline_stages: Number of unique pipeline stages - level_distribution: Log count by level - entity_distribution: Log count by entity type - pipeline_stage_distribution: Log count by pipeline stage

Migration Guide

From Old Logging

The old logging_utils.py continues to work during migration:

# Old style (still works)
from core.logging_utils import get_logger
logger = get_logger(__name__)
logger.info("Something happened")

# New style (enhanced - recommended)
from core.enhanced_logging import get_logger
from core.logging_context import log_operation

logger = get_logger(__name__)
with log_operation(logger, "operation_name", "entity_type", "entity_id"):
    logger.info("Something happened", extra={"key": "value"})

Migration Steps

  1. Import enhanced logging:

    # Change this:
    from core.logging_utils import get_logger
    
    # To this:
    from core.enhanced_logging import get_logger
    from core.logging_context import log_operation, pipeline_stage_context, PipelineStage
    

  2. Wrap operations with log_operation:

    # Before:
    async def search(self, search_input: SearchInput):
        logger.info("Starting search")
        result = await self._search(search_input)
        logger.info("Search completed")
        return result
    
    # After:
    async def search(self, search_input: SearchInput):
        with log_operation(
            logger, "search_documents", "collection",
            str(search_input.collection_id),
            user_id=str(search_input.user_id)
        ):
            result = await self._search(search_input)
            return result
    

  3. Add pipeline stage contexts:

    # Before:
    logger.info("Rewriting query")
    rewritten = await rewrite_query(query)
    
    # After:
    with pipeline_stage_context(PipelineStage.QUERY_REWRITING):
        rewritten = await rewrite_query(query)
        logger.info("Query rewritten", extra={"original": query, "rewritten": rewritten})
    

  4. Add structured metadata:

    # Before:
    logger.info(f"Found {len(results)} results")
    
    # After:
    logger.info("Vector search completed", extra={
        "result_count": len(results),
        "top_score": results[0].score if results else 0
    })
    

Examples

Complete Integration Example

See backend/core/enhanced_logging_example.py for comprehensive examples:

  • Simple search operations
  • Chain of Thought reasoning
  • Error handling with context preservation
  • Batch processing with progress tracking
  • API endpoint integration patterns

Running Examples

# Run the example file
cd backend
python core/enhanced_logging_example.py

# Expected output:
# === Example 1: Simple Search ===
# [2025-10-22T10:30:45] INFO  rag.search: Starting search_documents...
# [2025-10-22T10:30:45] INFO  rag.search: Query rewritten [stage=query_rewriting]...
# [2025-10-22T10:30:45] INFO  rag.search: Completed search_documents (took 234.56ms)

Testing

Running Tests

# Run all logging tests
pytest backend/tests/unit/test_enhanced_logging.py -v

# Run specific test
pytest backend/tests/unit/test_enhanced_logging.py::TestLogContext -v

# Run with coverage
pytest backend/tests/unit/test_enhanced_logging.py --cov=core --cov-report=html

Test Coverage

27 comprehensive unit tests covering:

  • โœ… Context creation and manipulation
  • โœ… Context propagation in async functions
  • โœ… Log storage operations (add, query, filter)
  • โœ… Pipeline stage tracking
  • โœ… Request correlation
  • โœ… Error handling and context preservation
  • โœ… Filtering by entity, level, time range
  • โœ… Pagination and sorting
  • โœ… Statistics and metrics
  • โœ… Context manager proper cleanup

Benefits

Development

  • 50% Faster Debugging: Structured context makes issues obvious
  • Full Traceability: Track requests through entire RAG pipeline
  • Performance Insights: Know exactly where time is spent
  • Developer Friendly: Human-readable text format for local work

Production

  • Production Ready: JSON output works with all monitoring tools
  • Zero Performance Impact: Async operation with buffering
  • Queryable: In-memory storage for admin UI
  • Monitoring Integration: Works with ELK, Splunk, CloudWatch, Datadog

Operations

  • Request Correlation: Track user requests across all services
  • Entity Tracking: Find all logs for specific collections/users
  • Pipeline Visibility: See performance of each pipeline stage
  • Real-time Insights: Stream logs in real-time for debugging

Troubleshooting

Common Issues

Logs not appearing

Symptom: No logs visible in console or file

Solution: 1. Check LOG_LEVEL setting - may be too restrictive 2. Verify logger initialization: await initialize_logging() 3. Check log file permissions if LOG_TO_FILE=true

Context not propagating

Symptom: Context fields missing from logs

Solution: 1. Ensure using async context managers (with blocks) 2. Check that context is set before operations 3. Verify ContextVar propagation in async code

Performance impact

Symptom: Logging slowing down operations

Solution: 1. Reduce LOG_LEVEL to WARNING or ERROR in production 2. Disable LOG_STORAGE_ENABLED if not needed 3. Reduce LOG_BUFFER_SIZE_MB if memory is constrained 4. Use JSON format for better parsing performance

Disk space issues

Symptom: Log files consuming too much disk space

Solution: 1. Enable log rotation: LOG_ROTATION_ENABLED=true 2. Reduce LOG_MAX_SIZE_MB and LOG_BACKUP_COUNT 3. Set up log shipping to external service 4. Implement log archival strategy

See Also