Update Skyflow environment validation to only support DEV and PROD

[samsternberg]

• Update skyflow-client.js to validate DEV and PROD environments
• Update handler.js to extract and pass X-Skyflow-Env header
• Update snowflake-handler.js to extract and pass sf-custom-X-Skyflow-Env header
• Update README.md with comprehensive environment configuration documentation
• Add environment examples for both standard and Snowflake integrations

[claude]

Pull Request Review - Environment Validation Update

Overview

This PR adds support for environment specification (DEV/PROD) via headers and implements validation to ensure only valid Skyflow environments are used. The changes are well-integrated across all three handlers.

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✅ Strengths

1. Consistent Implementation Across All Handlers

• The environment parameter is correctly threaded through all three handlers (handler.js, snowflake-handler.js)
• Proper default value of 'PROD' maintains backward compatibility
• Validation is centralized in skyflow-client.js:32-37 - excellent single source of truth

2. Excellent Documentation

• README.md updates are comprehensive and include examples for both DEV and PROD
• Snowflake-specific examples with the sf-custom- prefix are helpful
• Clear explanation that the header is optional with PROD as default

3. Client Caching Enhancement

• Client cache key updated to include environment: ${clusterId}:${vaultId}:${env} (line 39)
• This correctly ensures DEV and PROD clients are separate, preventing credential mixing
• Good logging added: "Initializing Skyflow client: cluster=..., vault=..., env=..."

4. Backward Compatibility

• All environment parameters default to 'PROD', ensuring existing integrations continue to work
• Optional header design is user-friendly

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🔍 Code Quality Observations

Architecture Adherence

✅ Pure SDK Wrapper Philosophy Maintained: The changes properly pass environment through to the Skyflow SDK without transformation, staying true to the project's pass-through design.

✅ Singleton Pattern Preserved: Client caching with environment in the key maintains warm invocation performance while properly isolating DEV/PROD clients.

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🐛 Potential Issues

1. Case Sensitivity in Environment Validation (Minor)

Location: skyflow-client.js:35

The validation is case-sensitive:

if (!validEnvironments.includes(env)) {
    throw new Error(`Invalid environment: ${env}. Must be one of: ${validEnvironments.join(', ')}`);
}

However, users might send 'prod', 'Prod', or 'dev' (lowercase). Consider normalizing to uppercase:

_getClient(clusterId, vaultId, env = 'PROD') {
    // Normalize to uppercase for case-insensitive matching
    const normalizedEnv = (env || 'PROD').toUpperCase();
    const validEnvironments = ['DEV', 'PROD'];
    
    if (!validEnvironments.includes(normalizedEnv)) {
        throw new Error(`Invalid environment: ${env}. Must be one of: ${validEnvironments.join(', ')} (case-insensitive)`);
    }

    const clientKey = `${clusterId}:${vaultId}:${normalizedEnv}`;
    // ... rest of method using normalizedEnv
}

This would improve developer experience by accepting X-Skyflow-Env: prod or X-Skyflow-Env: PROD.

2. Missing Environment Logging in handler.js (Minor)

Location: handler.js:64-122

The main handler doesn't log the environment value extracted from headers. Consider adding it to the initial log or to each operation's log for debugging:

console.log('Request:', {
    requestId: context.requestId,
    functionName: context.functionName,
    path: event.path || event.rawPath,
    operation: operation,
    environment: env,  // ADD THIS
    remainingTimeMs: context.getRemainingTimeInMillis()
});

This would help with troubleshooting production vs development issues.

---

🔒 Security Considerations

✅ No Security Issues Identified

• Environment parameter is properly validated before use
• No injection risks - the value is constrained to ['DEV', 'PROD']
• Client isolation is maintained (DEV and PROD clients are cached separately)

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⚡ Performance Considerations

✅ Excellent Performance Design

• Client caching with environment in key is optimal
• No additional network calls or overhead
• Validation happens before client initialization (fail-fast)

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🧪 Test Coverage

Current State

• Only utility function tests exist (headers.test.js)
• No tests for the new environment validation logic
• No integration tests for the handlers

Recommendations (Future Work - Not Blocking)

Consider adding tests for:

1. Environment validation: Test with 'DEV', 'PROD', 'prod', 'INVALID', null, undefined
2. Client caching: Verify separate clients for same vault with different environments
3. Header extraction: Test X-Skyflow-Env and sf-custom-X-Skyflow-Env extraction
4. Default behavior: Verify 'PROD' default when header is omitted

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📝 Documentation Quality

✅ Excellent Documentation Updates

• All affected sections of README.md updated
• Examples provided for both standard and Snowflake integrations
• Clear explanation of optional vs required headers
• Header table updated with environment field

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Recommendations Summary

Must Fix (Blocking) - None

Should Fix (Non-blocking)

1. Add case-insensitive environment matching - Improve UX by accepting lowercase/mixed case
2. Add environment to main handler logs - Aid debugging

Nice to Have (Future Work)

3. Add unit tests for environment validation - Ensure behavior is tested
4. Document environment behavior in CLAUDE.md - Update project guidance

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Final Verdict

✅ APPROVED with Minor Suggestions

This is a well-implemented feature that:

• Properly extends the existing architecture
• Maintains backward compatibility
• Includes excellent documentation
• Has no security or performance concerns

The suggestions above are minor improvements for developer experience. The PR can be merged as-is, with the improvements considered for a follow-up.

Great work on maintaining consistency across all three handler types! 🎉