Meet Khargo

Khargo is a Go (golang) HTTP file server with a GridFS (MongoDB) backend. If you want to store files in GridFS and serve them over HTTP, Khargo can help you out. It supports memory-efficient streaming of large files, and intelligent gzipping.

Running

Launch Khargo from the command line:

$ ./khargo 
2013/05/06 16:45:41 Connecting to mongodb://localhost:27017/test with strong consistency.
2013/05/06 16:45:41 Listening on :8000

Khargo accepts four command line arguments

• -consistency. Default: "strong". mgo driver consistency mode. One of eventual, monotonic, or strong. See http://godoc.org/labix.org/v2/mgo#Session.SetMode.
• -dburl. Default: mongodb://localhost:27017/test. See http://godoc.org/labix.org/v2/mgo#Dial for other values.
• -max-age. Default: 31557600 (one year). Lifetime (in seconds) for setting Cache-Control and Expires headers.
• -port. Default: 8000. Port to listen on.

Khargo does not daemonize.

The Khargo repository includes a Procfile that will launch Khargo as a 'web' proc. It expects $PORT and $DBURL environment variables to be set.

Compiling

Khargo is written in go. The only requirement outside the Go standard library is the mgo driver:

go get labix.org/v2/mgo
go build khargo.go

Logging

Khargo emits logs to stdout. Log lines look like this:

2013/05/06 15:05:03 10.0.2.2 - GET - /myfile.txt - curl/7.21.4 (universal-apple-darwin11.0) libcurl/7.21.4 OpenSSL/0.9.8r zlib/1.2.5 -  - 200 - 14.024ms

That format is:

date time ip - method - path - user agent - referer - status - response time

Uploading Files

The 'mongo' command line client is usually also installed with a mongofiles utility that you can use to upload files to GridFS. Here's an example of using it to upload this README file, from one directory up:

mongofiles put README.rst --local khargo/README.rst -h mymongoserver --db myfilesdb

The Name

I previously created a Python program called Khartoum that could serve GridFS files over http. Khargo is a rewrite in Go.