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Purpose

Implement metrics collection, logging, error tracking, health checks, and profiling for pipeline observability.

When To Use

• Adding monitoring/observability to a data pipeline framework
• Tracking pipeline execution metrics
• Implementing structured logging
• Setting up health checks
• Adding performance profiling

Preconditions

• Existing src/vibe_piper/ package structure
• Python 3.12+ environment
• UV package manager

Steps

1. Create monitoring module structure

mkdir -p src/vibe_piper/monitoring

2. Implement metrics collection (metrics.py)

• Create MetricType enum (COUNTER, GAUGE, HISTOGRAM, TIMER, SUMMARY)
• Create Metric dataclass (name, value, type, timestamp, labels, unit)
• Create MetricsSnapshot dataclass with filtering methods
• Create MetricsCollector class with:
  • start_execution() / end_execution() for pipeline-level metrics
  • record_metric() for custom metrics
  • record_asset_execution() for AssetResult integration
  • record_execution_result() for ExecutionResult integration
  • get_snapshot() / to_dict() for export
  • Thread-safe implementation with _lock

3. Implement structured logging (logging.py)

• Create LogLevel enum (TRACE, DEBUG, INFO, WARNING, ERROR, CRITICAL)
• Create JSONFormatter for machine-parsable logs
• Create ColoredFormatter for console output
• Create StructuredLogger wrapper with context support
• Create log_execution() context manager for pipeline tracing
• Create configure_logging() for setup

4. Implement health checks (health.py)

• Create HealthStatus enum (HEALTHY, DEGRADED, UNHEALTHY, UNKNOWN)
• Create HealthCheckResult dataclass
• Create HealthChecker class with:
  • register_check() / unregister_check() for dynamic checks
  • run_check() / run_all_checks() for execution
  • get_overall_health() for aggregate status
• Create factory functions: create_disk_space_check(), create_memory_check()

5. Implement error aggregation (errors.py)

• Create ErrorSeverity enum (LOW, MEDIUM, HIGH, CRITICAL)
• Create ErrorCategory enum (VALIDATION, CONNECTION, TRANSFORMATION, IO, TIMEOUT, SYSTEM, UNKNOWN)
• Create ErrorRecord dataclass with aggregation support
• Create ErrorAggregator class with:
  • add_error() for recording errors
  • Aggregation window for similar errors
  • Filtering methods (by severity, category, asset)
  • get_summary() for analytics

6. Implement profiling (profiling.py)

• Create ProfileData dataclass
• Create Profiler class with:
  • @profile decorator
  • get_stats() / get_history() for analysis
  • Optional psutil integration for memory tracking
• Create profile_execution() context manager

7. Update package exports

# Edit src/vibe_piper/__init__.py
# Add monitoring imports to __all__

8. Type checking and linting

uv run mypy src/vibe_piper/monitoring/
uv run ruff check src/vibe_piper/monitoring/ --fix
uv run ruff format src/vibe_piper/monitoring/

9. Create test suite

mkdir -p tests/monitoring

Create tests for:

• test_metrics.py: MetricsCollector, MetricsSnapshot, Metric
• test_logging.py: LogLevel, formatters, StructuredLogger, log_execution
• test_health.py: HealthChecker, health check functions
• test_errors.py: ErrorAggregator, ErrorRecord
• test_profiling.py: Profiler, ProfileData

10. Integration points

• MetricsCollector integrates with ExecutionEngine via record_execution_result()
• StructuredLogger can be used throughout codebase via get_logger()
• HealthChecker for system/resource health monitoring
• ErrorAggregator for tracking and alerting on errors

Examples

from vibe_piper.monitoring import (
    MetricsCollector,
    StructuredLogger,
    HealthChecker,
    ErrorAggregator,
    configure_logging,
)

# Configure logging
configure_logging(level=LogLevel.INFO, format_type="json")

# Collect metrics
metrics = MetricsCollector()
metrics.start_execution("my_pipeline", "run_123")
metrics.record_metric("custom_metric", 42)
metrics.end_execution()

# Health checks
health_checker = HealthChecker()
health_checker.register_check("disk", create_disk_space_check("/tmp"))
results = health_checker.run_all_checks()

Gotchas

• Optional psutil dependency: handle ImportError gracefully
• Thread-safety: use threading.Lock for shared state
• Type safety: use Optional[T] with proper None handling
• MyPy errors: use type: ignore[import-untyped] for untyped deps
• Formatter type mismatch: use separate variables for each formatter type
• Datetime arithmetic: coalesce None with datetime.utcnow()

Verification

uv run pytest tests/monitoring/ -v
uv run mypy src/vibe_piper/monitoring/ strict

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Manual notes

This section is preserved when the skill is updated. Put human notes, caveats, and exceptions here.