ln-733-env-configurator

Paths: File paths (references/, ../ln-*) are relative to this skill directory.

ln-733-env-configurator

Type: L3 Worker Category: 7XX Project Bootstrap

Configures environment variables for development and production environments.

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Purpose & Scope

Creates environment configuration files:

• Does: Generate .env files, update .gitignore for secrets protection
• Does NOT: Store secrets, manage external secrets managers, configure CI/CD secrets

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Inputs

Input	Source	Description
Project Name	Directory name	Used for database/service naming
Backend Port	Stack-dependent	5000 (.NET), 8000 (Python)
Frontend Port	Default	3000
Database Port	Default	5432
Detected Vars	Code analysis	Environment variables found in code

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Outputs

File	Purpose	Template
.env.example	Documented template	env_example.template
.env.development	Local development defaults	env_development.template
.env.production	Production placeholders	env_production.template
.gitignore (append)	Secrets protection	gitignore_secrets.template

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Workflow

Phase 1: Environment Discovery

Scan project for existing environment usage:

• Check for existing .env files
• Search code for process.env, os.environ, Configuration[]
• Identify which variables are secrets vs configuration

Output: List of required environment variables with types

Phase 2: Variable Classification

Classify discovered variables:

Category	Examples	Treatment
Database	DATABASE_URL, POSTGRES_*	Auto-generate with project name
API Config	API_PORT, LOG_LEVEL	Use detected or defaults
Security	JWT_SECRET, API_KEY	Placeholder with warning
External	REDIS_URL, SMTP_*	Comment out as optional

Phase 3: Template Generation

Generate environment files from templates:

1. Apply variable substitution
2. Include all discovered variables
3. Add comments for undocumented variables

Phase 4: Gitignore Update

Append secrets protection to .gitignore:

1. Read existing .gitignore (if exists)
2. Check if secrets patterns already present
3. Append missing patterns from template
4. Preserve existing entries

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Generated File Structure

.env.example

Documented template with all variables:

• Section headers (Database, Backend, Frontend, Security, External)
• Descriptive comments for each variable
• Safe placeholder values (never real secrets)
• Optional variables commented out

.env.development

Ready-to-use development configuration:

• Pre-filled values that work with docker-compose
• Development-only secrets (clearly marked)
• Debug-level logging enabled

.env.production

Production placeholder file:

• ${VARIABLE} syntax for deployment substitution
• Comments indicating required secrets
• Production-appropriate defaults (Warning log level)

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Security Best Practices

Practice	Implementation
No real secrets	Placeholder values only in templates
Gitignore protection	All .env files except .env.example
Development warnings	Mark dev secrets as insecure
Production guidance	Comments about secrets manager usage
Key rotation reminder	Note about regular secret rotation

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Security Notes

Generated files include these security reminders:

1. Never commit real secrets - .gitignore prevents accidental commits
2. Use secrets manager - GitHub Secrets, AWS Secrets Manager for production
3. Rotate secrets regularly - Especially JWT secrets
4. Strong JWT secrets - Minimum 256 bits (32 bytes)
5. Restrict CORS - Only allow necessary origins in production

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Quality Criteria

Generated files must:

• .env.example contains all required variables
• No real secrets or passwords in any file
• .gitignore updated with secrets patterns
• .env.development works with docker-compose
• .env.production uses placeholder syntax

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Critical Notes

1. Template-based: Use templates from references/. Do NOT hardcode file contents.
2. Idempotent: Check file existence. Append to .gitignore, don't overwrite.
3. No Real Secrets: Never generate files with actual passwords or API keys.
4. Development Safety: Development defaults should work out-of-box with docker-compose.

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Reference Files

File	Purpose
env_example.template	Documented .env template
env_development.template	Development defaults
env_production.template	Production placeholders
gitignore_secrets.template	.gitignore additions

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Definition of Done

• .env.example, .env.development, .env.production generated
• No real secrets or passwords in any generated file
• .gitignore updated with secrets protection patterns

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Version: 1.1.0 Last Updated: 2026-01-10