Listening on 127.0.0.1 raises a warning

[marvinroger]

New Issue Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.
• I can reproduce the issue with the latest version of Parse Server.

Issue Description

This was already raised in #4506, but the issue was closed.
When I start my Parse server listening on 127.0.0.1, I have the following warning:

  console.warn
    
    WARNING, Unable to connect to 'http://127.0.0.1:14744/api'. Cloud code and push notifications may be unavailable!
    

      at node_modules/parse-server/src/ParseServer.js:332:21

  console.warn
    Response: Error: connect ECONNREFUSED 127.0.0.1:14744
        at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1146:16) {
      errno: -61,
      code: 'ECONNREFUSED',
      syscall: 'connect',
      address: '127.0.0.1',
      port: 14744
    }

The problem comes from these lines: https://github.com/parse-community/parse-server/blob/alpha/src/ParseServer.js#L207-L209

There's a race condition here. When the app is mounted, the underlying server might not be listening yet.
When listening on localhost, the warning is not raised because of the DNS resolution (either on the listen or on the verifyServerUrl call), which takes some time. But when using an IP, like 127.0.0.1, the DNS resolution is skipped, the request from verifyServerUrl is done straight away, and the server is not yet listening, resulting in the warning.

I am not sure what can be done here (mount is not the right event to listen to, listening would be perfect, but this event does not exist from within a "sub" express app), except from removing this side-effect.

Steps to reproduce

Listen a Parse server with a server URL of 127.0.0.1

Actual Outcome

A warning

Expected Outcome

No warning

Environment

Server

• Parse Server version: 4.10.4
• Operating system: macOS 12.1
• Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc): Local

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[needpower]

@marvinroger I have the similar type of issue, but with localhost

WARNING, Unable to connect to 'https://parse-platform:1337/parse'. Cloud code and push notifications may be unavailable!

The important thing is that warning happens only when parse-server runs inside a Docker container.
But i can directly access to parse-server with REST API, for example:

POST https://localhost:1337/parse/classes/_User

So question here: where is the best place to ask for help/ideas how to resolve this? I'm not sure wether this is a problem in parse-server, or docker, or in my docker-compose configuration.

[needpower]

@marvinroger Hello!
Any news or updates on that?

[marvinroger]

Hi @needpower
I ended up creating an express app, bind it, then mounting the Parse server express app on it. Therefore, the server is already listening on Parse mount, and the warning is not raised 😉

[mtrezza]

A note for Parse Server 6; it's important to await starting Parse Server before adding it to the express app:

const parseServer = new ParseServer({ ... });
const expressApp = express();
await parseServer.start();
expressApp.use('/parse', parseServer.app);

Asynchronous start of Parse Server has been introduced with Parse Server 6; this issue was reported for Parse Server 4 and any version below Parse Server 6 is unsupported at this time, hence I'm closing this issue.