tracker/README.md

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 64-bit Go 1.4, Godep, and a Go environment previously set up.

$ 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

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 .

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:

http_listen_addr

type: string
default: ":6881"

The listen address for the HTTP server. If only a port is specified, the tracker will listen on all interfaces.

private_enabled

type: bool
default: true

Whether this is a public or private tracker.

purge_inactive_torrents

type: bool
default: true

If torrents should be forgotten when there are no active peers. This should be set to false for private trackers.

announce

type: duration
default: "30m"

The announce interval value sent to clients. This specifies how long clients should wait between regular announces.

min_announce

type: duration
default: "30m"

The announce min_interval value sent to clients. This theoretically specifies the minimum allowed time between announces, but most clients don't really respect it.

default_num_want

type: integer
default: 50

The default maximum number of peers to return if the client has not requested a specific number.

allow_ip_spoofing

type: bool
default: true

Whether peers are allowed to set their own IP via the various supported methods or if these are ignored. This must be enabled for dual-stack IP support, since there is no other way to determine both IPs of a peer otherwise.

dual_stacked_peers

type: bool
default: true

True if peers may have both an IPv4 and IPv6 address, otherwise only one IP per peer will be used.

real_ip_header

type: string
default: blank

An optional HTTP header indicating the upstream IP, for example X-Forwarded-For or X-Real-IP. Use this when running the tracker behind a reverse proxy.

respect_af

type: bool
default: false

Whether responses should only include peers of the same address family as the announcing peer, or if peers of any family may be returned (i.e. both IPv4 and IPv6).

client_whitelist_enabled

type: bool
default: false

Enables the peer ID whitelist.

client_whitelist

type: array of strings
default: []

List of peer ID prefixes to allow if client_whitelist_enabled is set to true.

freeleech_enabled

type: bool
default: false

For private trackers only, whether download stats should be counted or ignored for users.

torrent_map_shards

type: integer
default: 1

Number of internal torrent maps to use. Leave this at 1 in general, however it can potentially improve performance when there are many unique torrents and few peers per torrent.

• 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"