serve() error: "Uncaught InvalidData"

[nzakas]

I've been trying to run Deno in Google Cloud Run and while I could get my code to run locally using Docker, I kept getting the same error when trying to run in Cloud Run.

Code:

import { serve } from "https://deno.land/std@0.74.0/http/server.ts";

const PORT = Deno.env.get("PORT") || 8080;
const HOST = "0.0.0.0";

const server = serve({ hostname: HOST, port: PORT });
console.log(`HTTP webserver running.  Access it at:  http://${ HOST }:${ PORT }/`);

for await (const request of server) {
    request.respond({ status: 200, body: "Hello world!" });
}

The errors I received in Cloud Run are (may be a bit messed up, I tried unescaping the logs):

error: Uncaught InvalidData: data did not match any variant of untagged enum ArgsEnum
at Object.jsonOpSync (core.js:247:13)
at opListen ($deno$/cli/rt/30_net.js:32:17)
at Object.listen ($deno$/cli/rt/30_net.js:207:17)
at serve (server.ts:287:25)
at file:///app/src/index.js:22:16

My Dockerfile is:

FROM hayd/alpine-deno

WORKDIR /app
USER deno

EXPOSE $PORT

COPY . .
RUN deno cache src/index.js

CMD ["run", "--allow-net", "--allow-env", "src/index.js"]

This Dockerfile worked fine locally but I got an error when using in CloudRun. I was able to resolve the error by changing the argument to serve() to a string, like this:

// results in error
const server = serve({ hostname: HOST, port: PORT });

// results in error
const server = serve({ port: PORT });

// works
const server = serve(`${ HOST }:${ PORT }`);

I'm not sure quite what's happening, but it appears the validation is failing when passing in an object as the argument with the same data as the string.

From digging around in the source, it seems like this may be where the error is coming from.

Theory: The biggest difference between Cloud Run and my local setup is that Cloud Run pulls the value of PORT from an environment variable, which makes it a string, whereas my fallback value is a number (used locally). So, my guess is that somewhere in Deno, there is code expecting a number for the port, and when that check fails, this error occurs. I don't have the time to look at this further tonight but I can check tomorrow.

[lucacasonato]

which makes it a string, whereas my fallback value is a number (used locally). So, my guess is that somewhere in Deno, there is code expecting a number for the port, and when that check fails, this error occurs

This is exactly what I am thinking too. This could definitely use a more helpful error message.

[nzakas]

Just verified: indeed it is the case that if PORT is a string, I get this error. 👍 to having a better error message, though it seems like this could be addressed by converting to a number if the port value is not a number (Express does this, afaik).

[nzakas]

If anyone could point me in the right direction, I'd be happy to investigate and see if I can come up with a solution. Where could I start looking for where this error might be occurring?

[stale]

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