ln-771-logging-configurator

Type: L3 Worker Category: 7XX Project Bootstrap Parent: ln-770-crosscutting-setup

Configures structured JSON logging for .NET and Python projects.

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Overview

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

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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

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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)

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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

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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:
   • UseSerilog configuration
   • Request logging middleware
   • Enrichment configuration
3. 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:
   • Processor chain configuration
   • Renderer selection (JSON/Console)
   • Log level configuration
3. Generate logging_middleware.py for FastAPI

Packages to Add:

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

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Phase 5: Validate

Verify the configuration works.

Validation Steps:

1. Check imports: Ensure all packages are available

   • .NET: dotnet list package | grep Serilog
   • Python: pip list | grep structlog

2. Syntax check:

   • .NET: dotnet build --no-restore
   • Python: python -m py_compile core/logging_config.py

3. Test log output:

   • Start application
   • Make test request
   • 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
}

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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"
}

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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

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Reference Links

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

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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

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Version: 2.0.0 Last Updated: 2026-01-10