ln-771-logging-configurator

ln-771-logging-configurator

Type: L3 Worker Category: 7XX Project Bootstrap

Configures structured JSON logging for .NET and Python projects.

Overview

| Aspect | Details | |--------|---------| | Input | Context Store from ln-770 | | Output | Logging configuration files | | Stacks | .NET (Serilog), Python (structlog) |

Phase 1: Receive Context

Accept Context Store from coordinator.

Required Context:

• STACK: .NET or Python
• FRAMEWORK: ASP.NET Core or FastAPI
• FRAMEWORK_VERSION: Version number
• PROJECT_ROOT: Project directory path
• ENVIRONMENT: Development or Production

Validation:

• If STACK not provided, detect from project files
• If version not provided, use latest stable

Phase 2: Research Current Best Practices

Use MCP tools to get up-to-date documentation.

For .NET (Serilog):

MCP ref: "Serilog ASP.NET Core structured logging configuration"
Context7: /serilog/serilog-aspnetcore

For Python (structlog):

MCP ref: "structlog Python structured logging configuration"
Context7: /hynek/structlog

Key Patterns to Research:

1. Request logging middleware
2. Log enrichment (correlation ID, user context)
3. Log level configuration by environment
4. Sink configuration (Console, File, Seq, Elastic)

Phase 3: Decision Points

Ask user for configuration preferences.

Q1: Log Format

| Option | When to Use | |--------|-------------| | JSON (Recommended for Production) | Machine-readable, log aggregation systems | | Pretty/Colored (Recommended for Development) | Human-readable, local debugging |

Q2: Enrichment Fields

| Field | Description | Default | |-------|-------------|---------| | correlationId | Request tracking across services | ✓ Yes | | userId | Authenticated user identifier | ✓ Yes | | requestPath | HTTP request path | ✓ Yes | | responseTime | Request duration in ms | ✓ Yes | | machineName | Server hostname | Optional | | threadId | Thread identifier | Optional |

Q3: Log Sinks

| Sink | Use Case | |------|----------| | Console | Always enabled | | File | Local persistence, log rotation | | Seq | Structured log server | | Elasticsearch | Log aggregation at scale |

Q4: Log Levels by Environment

| Level | Development | Production | |-------|-------------|------------| | Default | Debug | Information | | Microsoft. | Information | Warning | | System. | Information | Warning | | Application | Debug | Information |

Phase 4: Generate Configuration

Generate files based on stack and decisions.

.NET Output Files

| File | Purpose | |------|---------| | Extensions/LoggingExtensions.cs | Service registration | | appsettings.json (update) | Serilog configuration | | appsettings.Development.json (update) | Dev overrides |

Generation Process:

1. Use MCP ref to get current Serilog API
2. Generate LoggingExtensions.cs with:
3. UseSerilog configuration
4. Request logging middleware
5. Enrichment configuration
6. Update appsettings.json with Serilog section

Packages to Add:

• Serilog.AspNetCore
• Serilog.Sinks.Console
• Serilog.Sinks.File (if File sink selected)
• Serilog.Enrichers.Environment (if machineName selected)

Python Output Files

| File | Purpose | |------|---------| | core/logging_config.py | structlog configuration | | middleware/logging_middleware.py | Request logging |

Generation Process:

1. Use MCP ref to get current structlog API
2. Generate logging_config.py with:
3. Processor chain configuration
4. Renderer selection (JSON/Console)
5. Log level configuration
6. Generate logging_middleware.py for FastAPI

Packages to Add:

• structlog
• python-json-logger (if JSON format)

Phase 5: Validate

Verify the configuration works.

Validation Steps:

1. Check imports: Ensure all packages are available
2. .NET: dotnet list package | grep Serilog
3. Python: pip list | grep structlog

1. Syntax check:
2. .NET: dotnet build --no-restore
3. Python: python -m py_compile core/logging_config.py

1. Test log output:
2. Start application
3. Make test request
4. Verify log format matches configuration

Expected Log Format:

{
  "timestamp": "2026-01-10T12:00:00.000Z",
  "level": "info",
  "message": "Request completed",
  "correlationId": "abc-123",
  "requestPath": "/api/health",
  "responseTime": 45,
  "statusCode": 200
}

Return to Coordinator

Return result to ln-770:

{
  "status": "success",
  "files_created": [
    "Extensions/LoggingExtensions.cs",
    "appsettings.json"
  ],
  "packages_added": [
    "Serilog.AspNetCore",
    "Serilog.Sinks.Console"
  ],
  "registration_code": "services.AddLoggingServices(configuration);",
  "message": "Configured structured logging with Serilog"
}

Idempotency

This skill is idempotent:

• Phase 1: Check if logging already configured (Grep for Serilog/structlog)
• If configured: Return { "status": "skipped", "message": "Logging already configured" }
• If not: Proceed with configuration

Reference Links

• Serilog.AspNetCore
• structlog Documentation
• ASP.NET Core Logging

Critical Rules

• Use MCP ref/Context7 for current API — do not hardcode Serilog/structlog config from memory
• Idempotent — if Serilog or structlog already configured, return status: "skipped" immediately
• Environment-aware log levels — Debug for Development, Information for Production (never Warning default)
• Always include correlation ID enrichment — required for distributed tracing
• Return structured response — files_created, packages_added, registration_code for coordinator aggregation

Definition of Done

• [ ] Context Store received and validated (stack, framework, version)
• [ ] Best practices researched via MCP tools for target stack
• [ ] User decisions collected (format, enrichment, sinks, log levels)
• [ ] Configuration files generated (extensions/config + appsettings or Python modules)
• [ ] Syntax validated (dotnet build or py_compile)
• [ ] Structured JSON response returned to ln-770 coordinator

Version: 2.0.0 Last Updated: 2026-01-10