dummyorigin

dummyorigin is a mock origin server to test the behavior of a CDN(or proxy).

The key feature is the arbitrary response header injection based on query string parameters in the request, allowing for great flexibility and ease-of-use. If the server gets request for /15kb.png?Cache-Control=no-cache&Dummy=Origin it serves the response with Cache-Control: no-cache and Dummy: Origin response headers.

dummyorigin comes with support for GZip, range requests, conditional requests, 404 and 301 responses.

Installation from source

go get github.com/turbobytes/dummyorigin

Usage

By default the server loads sample files into assets directory. Use -nofetch flag to override this.

dummyorigin -assets /tmp/dummyassets

Flags

-assets string
    Path to asset directory (default "assets")
-fetchonly
    Fetch demo assets and exit, i.e. no server
-http string
    listen addr for http server (default ":80")
-nofetch
    Do not fetch demo assets

Docker

The docker image turbobytes/dummyorigin comes pre-populated with sample files

docker run -it turbobytes/dummyorigin

To build an image with your own assets.

go get github.com/turbobytes/dummyorigin
cd $GOPATH/src/github.com/turbobytes/dummyorigin
mkdir assets
#At this point, put whatever you want in the assets directory
IMAGE=username/dummyorigin make all

This gives you a docker image called username/dummyorigin

Server behaviour

When a server gets a request, it does the following.

1. Add response header Access-Control-Allow-Origin: *
2. It looks at querystrings and sets headers using key as header name and value as header value. so ?foo=bar would become Foo: bar. Header names are canonicalized as per net/http
3. It adds response header X-Tb-Time with current time. This is done because most proxies override the Date header.
4. http.ServeFile. 404 if resource is missing, 301 to / for index.html. http.ServeFile might decide to overwrite some headers set in step 2
5. gziphandler.GzipHandler from package github.com/nytimes/gziphandler handles gzip.
6. The request and response details are written to console and optionally to loggly if LOGGLY_TOKEN environment variable is set.

Special error generator

When the server receives request in the format GET /err/<code> it returns with http status <code>.

<code> must be between 400 and 599. The URL should not have trailing slash.

Example:

$ curl --compress -v 127.0.0.1:10808/err/418?coffee=espresso
* Hostname was NOT found in DNS cache
*   Trying 127.0.0.1...
* Connected to 127.0.0.1 (127.0.0.1) port 10808 (#0)
> GET /err/418?Coffee=espresso HTTP/1.1
> User-Agent: curl/7.35.0
> Host: 127.0.0.1:10808
> Accept: */*
> Accept-Encoding: deflate, gzip
>
< HTTP/1.1 418 I'm a teapot
< Access-Control-Allow-Origin: *
< Coffee: espresso
< Content-Type: text/plain; charset=utf-8
< X-Content-Type-Options: nosniff
< X-Tb-Time: 2017-03-31 16:10:49.620647429 +0700 ICT
< Date: Fri, 31 Mar 2017 09:10:49 GMT
< Content-Length: 11
<
Error: 418
* Connection #0 to host 127.0.0.1 left intact
$