feat(rivetkit): configure server port via env (for serverless auto-start)

[abcxff]

Fixes CLD-37

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[abcxff]

• feat(rivetkit): configure server port via env (for serverless auto-start) #3640 👈 (View in Graphite)
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[linear]

CLD-37 rivetkit: Auto-start serverless with port from env

[claude]

Code Review

Thank you for this PR! I've reviewed the changes and found several issues that need to be addressed before merging.

Critical Issues

1. Missing Error Handling for Invalid Port Values

Location: rivetkit-typescript/packages/rivetkit/src/registry/run-config.ts:38-42

The current implementation uses parseInt() without proper error handling:

const defaultPort = getEnvUniversal("RIVET_SERVER_PORT");
if (typeof defaultPort === "undefined") {
    return 6420;
}
return parseInt(defaultPort);

Problems:

• parseInt() without a radix parameter can produce unexpected results
• No validation for invalid values (e.g., parseInt("abc") returns NaN)
• No error message for users when they provide invalid values

Recommended Fix:
Add radix parameter, validate port range (1-65535), and throw clear errors for invalid values.

2. Inconsistent Pattern with Other Environment Variables

Looking at similar environment variable handling in the codebase:

• client/config.ts uses .transform() for env vars
• drivers/engine/config.ts uses .transform() for env vars

Your PR uses .default(() => {...}) which is a different pattern. Consider using the .transform() pattern to match existing codebase style.

Minor Issues

3. Missing Test Coverage

There are no tests for this new environment variable functionality. Consider adding tests to verify:

• Default port (6420) is used when env var is not set
• Custom port is used when RIVET_SERVER_PORT is set
• Invalid values are rejected with clear error messages
• Boundary values (1, 65535) work correctly

Summary

Must Fix:

• Add radix parameter to parseInt() (use parseInt(envPort, 10))
• Add validation for port range (1-65535)
• Add error handling for NaN and out-of-range values

Should Consider:

• Match the .transform() pattern used elsewhere
• Add test coverage
• Document the new environment variable

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commit: b2a4261