Chihaya

Chihaya is a high-performance BitTorrent tracker written in the Go programming language. It is still heavily under development and the current master branch should probably not be used in production (unless you know what you're doing).

Features include:

• Public tracker feature-set with full compatibility with what exists of the BitTorrent spec
• Private tracker feature-set with compatibility for a Gazelle-like deployment (WIP)
• Low resource consumption, and fast, asynchronous request processing
• Full IPv6 support, including handling for dual-stacked peers
• Extensive metrics for visibility into the tracker and swarm's performance
• Ability to prioritize peers in local subnets to reduce backbone contention
• Pluggable backend driver that can coordinate with an external database

When would I use Chihaya?

Chihaya is a meant for every kind of BitTorrent tracker deployment. Chihaya has been used to replace instances of opentracker and also instances of ocelot. Chihaya handles torrent announces and scrapes in memory, but using a backend driver, can also asynchronously provide deltas to maintain a set of persistent data without throttling a database (this most useful for private tracker use-cases).

Building & Installing

Chihaya requires Go 1.4, Godep, and a Go environment previously setup.

$ export GOPATH=$PWD/chihaya
$ git clone github.com/chihaya/chihaya chihaya/src/github.com/chihaya/chihaya
$ godep go install chihaya/src/github.com/chihaya/cmd/chihaya

Configuration

Copy example_config.json to your choice of location, and update the values as required. The available keys and their default values are as follows:

• private_enabled: false – if this is a private tracker
• freeleech_enabled: false – for private trackers, whether download stats should be counted
• purge_inactive_torrents: true – if torrents should be forgotten after some time
• announce: "30m" – the announce "interval" value sent to clients
• min_announce: "15m" – the announce "min_interval" value sent to clients
• default_num_want: 50 – the default number of peers to return if the client has not specified
• torrent_map_shards: 1 – number of torrent maps to use (leave this at 1 in general)
• allow_ip_spoofing: true – if peers are allowed to set their own IP, this must be enabled for dual-stack IP support
• dual_stacked_peers: true – if peers may have both an IPv4 and IPv6 address, otherwise only one IP per peer will be used
• real_ip_header: "" – optionally an HTTP header where the upstream IP is stored, for example X-Forwarded-For or X-Real-IP
• respect_af: false – if responses should only include peers of the same address family as the announcing peer
• client_whitelist_enabled: false – if peer IDs should be matched against the whitelist
• client_whitelist: [] – list of peer ID prefixes to allow
• http_listen_addr: ":6881" – listen address for the HTTP server
• http_request_timeout: "10s"
• http_read_timeout: "10s"
• http_write_timeout: "10s"
• http_listen_limit: 0
• driver: "noop"
• stats_buffer_size: 0
• include_mem_stats: true
• verbose_mem_stats: false
• mem_stats_interval: "5s"

Testing

Chihaya has end-to-end test coverage for announces in addition to unit tests for isolated components. To run the tests, use:

$ cd $GOPATH/src/github.com/chihaya/chihaya
$ godep go test -v ./...

There is also a set of benchmarks for performance-critical sections of Chihaya. These can be run similarly:

$ cd $GOPATH/src/github.com/chihaya/chihaya
$ godep go test -v ./... -bench .