62 lines
1.9 KiB
Markdown
62 lines
1.9 KiB
Markdown
# ADR-0003: Environment Variable Validation at Startup
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## Status
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Accepted
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## Context
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The application was using environment variables without validation, leading to:
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- Runtime errors when required variables were missing
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- Security risks from weak or missing secrets
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- Difficult debugging when misconfigured
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- No clear error messages for configuration issues
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## Decision
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Implement environment variable validation that:
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- Runs at application startup
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- Validates all required variables
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- Provides clear error messages
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- Supports different validation rules per environment
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- Fails fast if critical variables are missing or invalid
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## Consequences
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### Positive
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- Early detection of configuration errors
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- Clear error messages guide developers
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- Prevents runtime failures from misconfiguration
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- Security improvements (validates JWT secret strength, CORS config)
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- Better developer experience
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### Negative
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- Application won't start if validation fails (by design)
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- Requires maintaining validation schema
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- Additional startup time (minimal)
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### Risks
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- Breaking changes if validation rules are too strict
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- Need to keep validation in sync with actual usage
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## Alternatives Considered
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1. **Runtime Validation**: Validate when variables are used
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- Pros: More flexible
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- Cons: Errors discovered late, harder to debug
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2. **Configuration File**: Use config file instead of env vars
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- Pros: Type-safe, validated
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- Cons: Doesn't work well with 12-factor app principles
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3. **Startup Validation**: Chosen approach
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- Pros: Fail fast, clear errors, secure defaults
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- Cons: None significant
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## Implementation
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- Created `src/shared/config/env-validator.ts`
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- Integrated into `src/index.ts` startup
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- Validates: DATABASE_URL, JWT_SECRET, ALLOWED_ORIGINS, etc.
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## References
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- 12-Factor App: https://12factor.net/config
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- Node.js Environment Variables: https://nodejs.org/en/learn/command-line/how-to-read-environment-variables-from-nodejs
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