Simple echo service

Plain and very simple echo service usefully for testing infrastructure components.

A docker image is available on Docker Hub and ghcr.io.

Build & Test

Install the latest go version: https://go.dev/doc/install

• Resolve dependencies: go get -d -v
• Build: go build -v ./...
• Test: go test -v ./...

Security

The provided docker images are small and secure. The latest stable go version will be used to compile and link to a static binary. The binary is started as non root User. The User has no shell, no home directory and no ability to login. The smallest possible image is used: FROM scratch

Usage

The binary can be started via ./echo-service. By default, it listens on port 8080. You can change the listen port by setting the environment variable echo_service_port.

When setting the environment variable instance_name a custom instance name will be send with each response.

JWT Bearer Token

If using a JWT Bearer token it will be decoded (without verifying!) and send back as JSON.

Timeout simulation

You can specify time periods the echo-service will sleep to simulate timeout handling in e.g. a gateway. All durations can be used with a time unit. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h". The duration can be send as Query Param (timeout=30s) or HTTP Header (X-Timeout: 5000ms)

Output

If called with a Chrome browser this is the output:

{
  "http": {
    "method": "GET",
    "protocol": "HTTP/1.1",
    "host": "localhost:8080"
  },
  "header": {
    "Accept": [
      "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9"
    ],
    "Accept-Encoding": [
      "gzip, deflate, br"
    ],
    "Accept-Language": [
      "de-DE,de;q=0.9,en-US;q=0.8,en;q=0.7"
    ],
    "Connection": [
      "keep-alive"
    ],
    "Dnt": [
      "1"
    ],
    "Sec-Ch-Ua": [
      "\"Not_A Brand\";v=\"99\", \"Google Chrome\";v=\"109\", \"Chromium\";v=\"109\""
    ],
    "Sec-Ch-Ua-Mobile": [
      "?0"
    ],
    "Sec-Ch-Ua-Platform": [
      "\"macOS\""
    ],
    "Sec-Fetch-Dest": [
      "document"
    ],
    "Sec-Fetch-Mode": [
      "navigate"
    ],
    "Sec-Fetch-Site": [
      "none"
    ],
    "Sec-Fetch-User": [
      "?1"
    ],
    "Upgrade-Insecure-Requests": [
      "1"
    ],
    "User-Agent": [
      "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36"
    ]
  },
  "remoteAddress": "[::1]:60259",
  "request": {
    "requestURI": "/foo/bar?q=v",
    "path": "/foo/bar",
    "queryString": "q=v",
    "body": ""
  },
  "authorization" : {
    "header" : {
      "alg": "HS256",
      "typ": "JWT"
    },
    "payload" : {
      "sub": "1234567890",
      "name": "John Doe",
      "iat": 1516239022,
      "customClaim": "Foo"
    }
  }
}