TL;DR

I can’t send HTTP request to local docker container (accessible via 127.0.0.1:4002) through Kong gateway.

Kong Gateway components:

• Service test_service: url=http://127.0.0.1:4002;
• Route test_route: paths[]=/test, name=test_route;

Request to Kong proxy:

$ curl -X GET http://localhost:8000/test
{
  "message":"An invalid response was received from the upstream server",
  "request_id":"9aba1e35ea54222d9fd27c4e2eeea850"
}

Long Version

I created a simple Express app that responds to HTTP requests with "Foo" and "Bar", and dockerized it.

Application

index.js:

const express = require('express');

const app = express();
var port = 4002;

app.use("/foo", (req, res) => {
    res.send("Foo");
});

app.use("/bar", (req, res) => {
  res.send("Bar");
});

app.use((req, res) => {
  res.send("Test unknown path");
});

app.listen(port, () => {
  console.log(`Foo-bar listening on port ${port}`)
})

Dockerfile:

FROM node:lts-alpine
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 4002
CMD ["node", "index.js"]

After building and running it, I can send HTTP requests to "localhost:4002" and correctly get the responses.

Example:

$ docker ps
CONTAINER ID   IMAGE                        COMMAND                  CREATED              STATUS                 PORTS                                             NAMES
fce1cc4e7b24   mikyll/test-service:latest   "docker-entrypoint.s…"   About a minute ago   Up About a minute      0.0.0.0:4002->4002/tcp                            nice_blackwell

$ curl -X GET http://localhost:4002
Test unknown path

$ curl -X GET http://localhost:4002/foo
Foo

$ curl -X GET http://localhost:4002/bar
Bar

Kong Setup

I followed the instructions to setup Kong Gateway on Docker and manage services and routes:

1. I run Kong Gateway container:

curl -Ls https://get.konghq.com/quickstart | bash

2. Tested the connection:

$ curl --head localhost:8001
HTTP/1.1 200 OK
[...]

3. Created a service:

$ curl -i -s -X POST http://localhost:8001/services --data name=test_service --data url='http://127.0.0.1:4002'
HTTP/1.1 201 Created
[...]

Service JSON:

{
  "data":[
    {
      "retries":5,
      "tls_verify":null,
      "protocol":"http",
      "port":4002,
      "updated_at":1700054325,
      "created_at":1700054325,
      "connect_timeout":60000,
      "read_timeout":60000,
      "client_certificate":null,
      "host":"127.0.0.1",
      "path":null,
      "name":"test_service",
      "enabled":true,
      "tags":null,
      "write_timeout":60000,
      "ca_certificates":null,
      "id":"e79539ca-603b-4237-8abd-6ff07bd73160",
      "tls_verify_depth":null
    }
  ],
  "next":null
}

4. Created a route:

$ curl -i -X POST http://localhost:8001/services/test_service/routes --data 'paths[]=/test' --data name=test_route

Route JSON:

{
  "data":[
    {
      "https_redirect_status_code":426,
      "service":{
        "id":"e79539ca-603b-4237-8abd-6ff07bd73160"
      },
      "id":"4b04a262-6229-4361-9b2c-88f00b0fe6c2",
      "hosts":null,
      "path_handling":"v0",
      "updated_at":1700054404,
      "created_at":1700054404,
      "preserve_host":false,
      "headers":null,
      "methods":null,
      "sources":null,
      "destinations":null,
      "paths":[
        "/test"
      ],
      "snis":null,
      "name":"test_route",
      "tags":null,
      "request_buffering":true,
      "response_buffering":true,
      "protocols":[
        "http",
        "https"
      ],
      "regex_priority":0,
      "strip_path":true
    }
  ],
  "next":null
}

Problem

When I try to send an HTTP request, I get the error "An invalid response was received from the upstream server.":

$ curl -X GET http://localhost:8000/test
{
  "message":"An invalid response was received from the upstream server",
  "request_id":"9aba1e35ea54222d9fd27c4e2eeea850"
}

Question

Is my configuration (service/route) wrong? Am I missing some setup step?