config-consistency-checker

# Config Consistency Checker

Automatically detect inconsistencies, conflicts, and mismatches in configuration files across environments and modules.

## Workflow

### 1. Parse Configuration Files

Read and parse configuration files in various formats:
- JSON (.json)
- YAML (.yml, .yaml)
- TOML (.toml)
- INI (.ini)
- XML (.xml)
- Environment files (.env)
- Properties files (.properties)

### 2. Extract Structure

Build configuration structure:
- Key-value pairs
- Nested objects/sections
- Arrays/lists
- Data types

### 3. Compare Configurations

Compare across:
- **Environments**: dev vs staging vs production
- **Versions**: v1 vs v2
- **Modules**: service-a vs service-b
- **Templates**: actual vs expected

### 4. Detect Issues

Identify:
- Missing required keys
- Conflicting values
- Type mismatches
- Divergent settings
- Deprecated keys
- Security issues

### 5. Generate Report

Provide:
- Detailed inconsistency list
- Critical issues highlighted
- Resolution guidance
- Suggested fixes

## Quick Examples

### Example 1: Environment Mismatch

**dev.json:**
```json
{
  "database": {
    "host": "localhost",
    "port": 5432,
    "ssl": false
  }
}
```

**prod.json:**
```json
{
  "database": {
    "host": "prod-db.example.com",
    "port": 5432
  }
}
```

**Issues Detected:**
- Missing key: `prod.json` missing `database.ssl`
- **Critical**: SSL disabled in dev but undefined in prod

**Resolution:**
Add `"ssl": true` to prod.json

### Example 2: Type Mismatch

**config-a.yaml:**
```yaml
timeout: 30
```

**config-b.yaml:**
```yaml
timeout: "30"
```

**Issue:** Type mismatch (number vs string)

**Resolution:** Standardize to number: `timeout: 30`

### Example 3: Security Issue

**config.env:**
```
DATABASE_PASSWORD=secret123
API_KEY=hardcoded-key-here
```

**Issues:**
- Hardcoded password
- Hardcoded API key

**Resolution:** Use environment variables or secrets manager

## Detection Patterns

### Missing Keys

Compare key sets across configs:
```
Config A keys: {host, port, ssl}
Config B keys: {host, port}
Missing in B: {ssl}
```

### Conflicting Values

Same key, different values:
```
dev.timeout = 30
prod.timeout = 60
→ Divergent (may be intentional)
```

### Type Mismatches

Same key, different types:
```
config-a.port = 8080 (number)
config-b.port = "8080" (string)
→ Type inconsistency
```

### Security Issues

Detect patterns:
- `password`, `secret`, `key` with hardcoded values
- Weak settings: `ssl: false`, `debug: true` in production
- Exposed credentials

## Report Format

```
Configuration Consistency Report
================================

Files Analyzed:
- dev.json
- staging.json
- prod.json

Summary:
- Total Issues: 5
- Critical: 2
- Warnings: 3

Critical Issues:
1. Missing Key: prod.json missing 'database.ssl'
   Impact: SSL may be disabled in production
   Resolution: Add "ssl": true to prod.json

2. Security Issue: Hardcoded password in dev.json
   Impact: Credentials exposed in config file
   Resolution: Use environment variable ${DB_PASSWORD}

Warnings:
3. Type Mismatch: timeout is number in dev, string in staging
   Resolution: Standardize to number type

4. Divergent Value: max_connections differs (dev:10, prod:100)
   Note: May be intentional for different environments

5. Deprecated Key: 'legacy_mode' is deprecated
   Resolution: Remove or migrate to new setting
```

## Best Practices

- **Environment-specific values**: Document intentional differences
- **Type consistency**: Use same types across environments
- **Required keys**: Define and validate required configuration
- **Security**: Never hardcode secrets
- **Validation**: Use schemas to enforce structure
- **Documentation**: Comment why values differ

## Common Scenarios

### Multi-Environment Setup

Compare dev, staging, prod configs to ensure consistency while allowing intentional differences.

### Microservices

Validate that shared configuration keys are consistent across services.

### Configuration Migration

Detect missing or changed keys when upgrading configuration versions.

### Security Audit

Scan for hardcoded secrets and insecure settings.

## Tips

- Start with critical keys (database, security settings)
- Document intentional differences
- Use configuration schemas for validation
- Automate checks in CI/CD pipeline
- Review security issues immediately