go-httpbin

A reasonably complete and well-tested golang port of Kenneth Reitz's httpbin service, with zero dependencies outside the go stdlib.

Usage

Configuration

go-httpbin can be configured via either command line arguments or environment variables (or a combination of the two):

Argument	Env var	Documentation	Default
-host	HOST	Host to listen on	"0.0.0.0"
-https-cert-file	HTTPS_CERT_FILE	HTTPS Server certificate file
-https-key-file	HTTPS_KEY_FILE	HTTPS Server private key file
-max-body-size	MAX_BODY_SIZE	Maximum size of request or response, in bytes	1048576
-max-duration	MAX_DURATION	Maximum duration a response may take	10s
-port	PORT	Port to listen on	8080
-use-real-hostname	USE_REAL_HOSTNAME	Expose real hostname as reported by os.Hostname() in the /hostname endpoint	false

Note: Command line arguments take precedence over environment variables.

Standalone binary

Follow the Installation instructions to install go-httpbin as a standalone binary. (This currently requires a working Go runtime.)

Examples:

# Run http server
$ go-httpbin -host 127.0.0.1 -port 8081

# Run https server
$ openssl genrsa -out server.key 2048
$ openssl ecparam -genkey -name secp384r1 -out server.key
$ openssl req -new -x509 -sha256 -key server.key -out server.crt -days 3650
$ go-httpbin -host 127.0.0.1 -port 8081 -https-cert-file ./server.crt -https-key-file ./server.key

Docker

Docker images are published to Docker Hub:

# Run http server
$ docker run -P mccutchen/go-httpbin

# Run https server
$ docker run -e HTTPS_CERT_FILE='/tmp/server.crt' -e HTTPS_KEY_FILE='/tmp/server.key' -p 8080:8080 -v /tmp:/tmp mccutchen/go-httpbin

Unit testing helper library

The github.com/mccutchen/go-httpbin/httpbin/v2 package can also be used as a library for testing an application's interactions with an upstream HTTP service, like so:

package httpbin_test

import (
	"net/http"
	"net/http/httptest"
	"os"
	"testing"
	"time"

	"github.com/mccutchen/go-httpbin/v2/httpbin"
)

func TestSlowResponse(t *testing.T) {
	app := httpbin.New()
	testServer := httptest.NewServer(app.Handler())
	defer testServer.Close()

	client := http.Client{
		Timeout: time.Duration(1 * time.Second),
	}

	_, err := client.Get(testServer.URL + "/delay/10")
	if !os.IsTimeout(err) {
		t.Fatalf("expected timeout error, got %s", err)
	}
}

Custom instrumentation

If you're running go-httpbin in your own infrastructure and would like custom instrumentation (metrics, structured logging, request tracing, etc), you'll need to wrap this package in your own code and use the included Observer mechanism to instrument requests as necessary.

See examples/custom-instrumentation for an example that instruments every request using DataDog.

Installation

To add go-httpbin to an existing golang project:

go get -u github.com/mccutchen/go-httpbin/v2

To install the go-httpbin binary:

go install github.com/mccutchen/go-httpbin/v2/cmd/go-httpbin

Motivation & prior art

I've been a longtime user of Kenneith Reitz's original httpbin.org, and wanted to write a golang port for fun and to see how far I could get using only the stdlib.

When I started this project, there were a handful of existing and incomplete golang ports, with the most promising being ahmetb/go-httpbin. This project showed me how useful it might be to have an httpbin library available for testing golang applications.

Known differences from other httpbin versions

Compared to the original:

• No /brotli endpoint (due to lack of support in Go's stdlib)
• The ?show_env=1 query param is ignored (i.e. no special handling of runtime environment headers)
• Response values which may be encoded as either a string or a list of strings will always be encoded as a list of strings (e.g. request headers, query params, form values)

Compared to ahmetb/go-httpbin:

• No dependencies on 3rd party packages
• More complete implementation of endpoints

Development

# local development
make
make test
make testcover
make run

# building & pushing docker images
make image
make imagepush