"Error: read UNKNOWN" error when using TLS to connect to database using mysql2

[DMeechan]

When using Deno 1.36.3 I get this Uncaught (in promise) Error: read UNKNOWN error when running the script below:

error: Uncaught (in promise) Error: read UNKNOWN
    at createConnection (file:///home/u/node-vs-deno-db-drivers/node_modules/.deno/mysql2@3.6.0/node_modules/mysql2/promise.js:253:31)
    at file:///home/u/node-vs-deno-db-drivers/mysql2.ts:12:28
    at file:///home/u/node-vs-deno-db-drivers/mysql2.ts:21:1

When using Deno 1.36.1 (which precedes #20120) I get an Uncaught Error: tlssock._start is not a function error when running the script:

error: Uncaught Error: tlssock._start is not a function
    at createConnection (file:///home/u/node-vs-deno-db-drivers/node_modules/.deno/mysql2@3.6.0/node_modules/mysql2/promise.js:253:31)
    at file:///home/u/node-vs-deno-db-drivers/mysql2.ts:12:28
    at file:///home/u/node-vs-deno-db-drivers/mysql2.ts:21:1

Given that the stack trace indicates the Error: read UNKNOWN error is being thrown from the same place as the Uncaught Error: tlssock._start is not a function error was, I'm thinking it may be a TLS-related issue in Deno.

I've tested the script below with Node v18.17.1 and it runs fine.

How to reproduce

Create mysql2.ts:

// Swap the commenting on these two lines if you're testing this on Node.js vs Deno
import { createConnection } from "npm:mysql2@^3.6.0/promise"; // For Deno
// import { createConnection } from "mysql2/promise"; // For Node.js

import { readFileSync } from "node:fs";
const cert = readFileSync("/etc/ssl/certs/ca-certificates.crt"); // I'm using Ubuntu - this certificate path may be different for your OS
const planetscaleMysqlUrl = "SOME_MYSQL_URL_HERE";

(async () => {
  const connection = await createConnection({
    uri: planetscaleMysqlUrl,
    ssl: { ca: cert },
  });

  const result = await connection.execute("SELECT 1");
  console.log(result);

  connection.end();
})();

In Deno

Run the script above using Deno 1.36.3: deno run -A mysql2.ts

In Node.js

Using v18.17.1:

1. npm init -y
2. Add "type": "module" to package.json
3. npm install mysql2@3.6.0
4. Copy or rename the file to .js (it's easier): cp mysql2.ts mysql2.js
5. Swap the import comments on lines 2 and 3 of mysql2.js
6. node mysql2.js

[brundonsmith]

I'm getting this too (was getting the tlssock._start error on Deno v1.36.1, and now Error: read UNKNOWN on Deno v1.36.3), but with the pg-pool library instead of mysql

[littledivy]

This may be caused by a race condition in the socket buffer which was fixed in canary (deno upgrade --canary). Can you give it a try maybe it fixes the issue?

[DMeechan]

@littledivy I just updated to deno 1.36.3+64045eb and I'm getting the same error

[DMeechan]

Hello 👋 I just tried the same thing with mariadb driver on the latest Deno canary release (deno 1.36.3+c9223bc) and I get the same error but with a different stack trace:

import mariadb from "npm:mariadb@^3.2.0";
const connection = await mariadb.createConnection({
  host: hostname,
  database: db,
  user: username,
  password,
  ssl: true,
});

// Result:
error: Uncaught (in promise) Error: read UNKNOWN
    at __node_internal_captureLargerStackTrace (ext:deno_node/internal/errors.ts:91:9)
    at __node_internal_errnoException (ext:deno_node/internal/errors.ts:139:10)
    at TCP.onStreamRead [as onread] (ext:deno_node/internal/stream_base_commons.ts:209:20)
    at TCP.#read (ext:deno_node/internal_binding/stream_wrap.ts:277:14)
    at eventLoopTick (ext:core/01_core.js:183:11)

[littledivy]

Thanks, will look into it.

[littledivy]

It seems the underlying error was not propogated. I am getting "Unsupported Certificate" error. And the example works if I use deno run with --unsafely-ignore-certificate-errors.

[DMeechan]

Thanks @littledivy! I'll give that a try!

Do you know why we'd be getting an unsupported certificate error in Deno, while it runs ok in Node? Is there a different (type of) certificate we should be using?

[chromakode]

I'm also seeing this Error: read UNKNOWN error using Deno 1.38.4 to connect to a postgres server using TLS with the npm:pg library.

[chromakode]

Tracing through the debugger, the underlying error I'm getting is NotValidForName. It'd be useful to expose this to the user somehow, since currently these errors are difficult to debug. If it'd be difficult to thread the error context up through nread, would a console.error() here be viable for the "UNKNOWN" type errors?

[chromakode]

Aha! The underlying issue here is that tlsOptions.hostname is not being set here:

deno/ext/node/polyfills/_tls_wrap.ts

Lines 87 to 89 in f6b889b

	let hostname = tlsOptions?.secureContext?.servername;
	hostname = opts.host;
	tlsOptions.hostname = hostname;

It appears the value arrives here in opts.servername. After setting tlsOptions.hostname = opts.servername in the debugger I get a successful connection.