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ETORRENT
ETORRENT is a bittorrent client written in Erlang. The focus is on robustness and scalability in number of torrents rather than in pure speed. ETORRENT is mostly meant for unattended operation, where one just specifies what files to download and gets a notification when they are.
Flag days
Flag days are when you need to do something to your setup
- 2010-12-10 You will need a rebar with commit 618b292c3d84 as we got some fixes into rebar.
- 2010-12-06 We now depend on riak_err. You will need to regrab dependencies.
- 2010-12-02 The fast-resume-file format has been updated. You may have to delete your fast_resume_file though the system was configured to do a silent system upgrade.
Build Status
Currently, we are running build-bots through
[http://travis-ci.org](Travis CI).
Why
ETORRENT was mostly conceived as an experiment in how easy it would be to write a bittorrent client in Erlang. The hypothesis is that the code will be cleaner and smaller than comparative bittorrent clients.
Maturity
The code is at this point somewhat mature. It has been used in several scenarios with a good host of different clients and trackers. The code base is not known to act as a bad p2p citizen, although it may be possible that it is.
The most important missing link currently is that only a few users
have been testing it - so there may still be bugs in the code. The
master
branch has been quite stable for months now however, so it is
time to get some more users for testing. Please report any bugs,
especially if the client behaves badly.
Currently supported BEPs:
- BEP 03 - The BitTorrent Protocol Specification.
- BEP 04 - Known Number Allocations.
- BEP 05 - DHT Protocol
- BEP 10 - Extension Protocol
- BEP 12 - Multitracker Metadata Extension.
- BEP 15 - UDP Tracker Protocol
- BEP 23 - Tracker Returns Compact Peer Lists.
Required software:
-
rebar - you need a working rebar installation to build etorrent. The rebar must have commit 618b292c3d84. It is known that rebar version
rebar version: 2 date: 20110310_155239 vcs: git 2e1b4da
works, and later versions probably will too. -
Erlang/OTP R13B04 or R14 - the etorrent system is written in Erlang and thus requires a working Erlang distribution to work. It may work with older versions, but has mostly been tested with newer versions.
If you have the option, running on R14B02 is preferred. The developers are usually running on fairly recent Erlang/OTP releases, so you have much better chances with these systems.
-
A UNIX-derivative or Windows as the operating system Support has been tested by mulander and is reported to work with some manual labor. For details see the Windows getting started section.
GETTING STARTED
make deps
- Pull the relevant dependencies into deps/make compile
- this compiles the source codemake rel
- this creates an embedded release in rel/etorrent which can subsequently be moved to a location at your leisure.- edit
${EDITOR} rel/etorrent/etc/app.config
- there are a number of directories which must be set in order to make the system work. - check
${EDITOR} rel/etorrent/etc/vm.args
- Erlang args to supply - be sure to protect the erlang cookie or anybody can connect to your erlang system! See the Erlang user manual in distributed operation
- run
rel/etorrent/bin/etorrent console
- drop a .torrent file in the watched dir and see what happens.
- call
etorrent:help()
. from the Erlang CLI to get a list of available commands. - If you enabled the webui, you can try browsing to its location. By default the location is 'http://localhost:8080'.
GETTING STARTED (Windows)
-
Obviously get and install erlang from erlang.org. This process was tested with R14B01 release. You may want to add the bin directory to your PATH in order to reduce the length of the commands you will enter later on.
-
Install msysgit. Tested with 1.7.3.1.msysgit.0.
-
Install Win32 OpenSSL. The installer hang on me midway through the process but the libs were properly copied to C:\Windows\system32.
-
Confirm that your crypto works correctly by running
crypto:start().
from an erlang shell (Start->Erlang OTP R14B01->Erlang). The shell should respond withok
. If you get an error then your openssl libraries are still missing. -
Open up a git bash shell and cd to a directory you want to work in.
-
Clone the rebar repository
git clone https://github.com/basho/rebar.git
-
From a regular cmd.exe shell
cd rebar
. Now if you added the erlang bin directory to your PATH then you can simply runbootstrap.bat
. If you didn't add Erlang's bin to your path then issue the following command:"C:\Program Files\erl5.8.2\bin\escript.exe" bootstrap
Adjust the path to your Erlang installation directory. From now on, use this invocation for escript.exe and erl.exe. I'll assume it's on PATH. You should now have a
rebar
file created. If you have Erlangs bin dir on your PATH then you may want to also add the rebar directory to your PATH. This will allow you to use the rebar.bat script which will also reduce the amount of typing you will have to do. -
Clone etorrent and copy the
rebar
file into it (unless you have it on path). -
Now, we need to satisfy the dependencies. This should be done by rebar itself but I couldn't get it to work correctly with git. This point describes how to do it manually.
mkdir deps
# this is where rebar will look for etorrent dependenciesescript.exe rebar check-deps
# this will give you a list of the missing dependencies and their git repos.For each dependency reported by check-deps perform the following command in a git bash shell (be sure to be in the etorrent directory)
git clone git://path_to_repo/name.git deps/name
Be sure to run
escript.exe rebar check-deps
after cloning each additional repo as new dependencies might be added by them.For the time of this writing (2011-02-13) I had to clone the following repositories:
git clone git://github.com/esl/gproc.git deps/gproc
git clone git://github.com/esl/edown.git deps/edown
git clone git://github.com/basho/riak_err.git deps/riak_err
-
escript.exe rebar compile
to compile the application from a cmd.exe prompt. -
escript.exe rebar generate
this creates an embedded release in rel/etorrent which can subsequently be moved to a location at your leisure. This command may take some time so be patient. -
Edit
rel/etorrent/etc/app.config
- there are a number of directories which must be set in order to make the system work. Be sure each directory exists before starting etorrent. You also have to change all paths starting with/
(ie./var/lib...
). When setting paths use forward slashes. For example{dir, "D:/etorrent/torrents"},
. -
Check
rel/etorrent/etc/vm.args
- Erlang args to supply -
Be sure to protect the erlang cookie or anybody can connect to your erlang system! See the Erlang user manual in distributed operation
-
We can't run the etorrent script because it's written in bash. So in order to start ettorent cd from a cmd.exe shell into the
rel\etorrent
directory. And perform the following commanderts-5.8.2\bin\erl.exe -boot release\1.2.1\etorrent -embedded -config etc\app.config -args_file etc\vm.args
Be sure to substitute the version number in the release path to the current etorrent release version. Do the same for the erts version. Allow port communication when/if the Windows firewall asks for it.
-
drop a .torrent file in the watched dir and see what happens.
-
call
etorrent:help()
. from the Erlang CLI to get a list of available commands. -
If you enabled the webui, you can try browsing to its location. By default the location is 'http://localhost:8080'.
Testing etorrent
Read the document etorrent/TEST.md for how to run tests of the system.
Troubleshooting
If the above commands doesn't work, we want to hear about it. This is a list of known problems:
-
General: Many distributions are insane and pack erlang in split packages, so each part of erlang is in its own package. This always leads to build problems due to missing stuff. Be sure you have all relevant packages installed. And when you find which packages are needed, please send a patch to this file for the distribution and version so we can keep it up-to-date.
-
Ubuntu 10.10: Ubuntu has a symlink
/usr/lib/erlang/man -> /usr/share/man
. This is insane and generates problems when building a release (spec errors on missing files if a symlink points to nowhere). The easiest fix is to remove the man symlink from/usr/lib/erlang
. A way better fix is to install a recent Erlang/OTP yourself and use Begone(tm) on the supplied version.
Installing Erlang
I (jlouis@) use the following commands to install Erlang:
- Install stow,
sudo aptitude install stow
- Execute
sudo aptitude build-dep erlang
to pull in all build dependencies we need. - Execute
git clone git://github.com/erlang/otp.git
- Get into the directory and fire away
git checkout dev && ./otp_build autoconf
- Get a useful tag for the otp version you have built
otp_version=$(git describe)
./configure --prefix=/usr/local/stow/${otp_version}
make; make docs
make install install-docs
And then I enable it in stow:
cd /usr/local/stow && stow ${otp_version}
You may have to use stow -D
on an old
Another way is to use Basho kerl, a simple shell script:
$ curl -O https://raw.github.com/spawngrid/kerl/master/kerl; chmod a+x kerl
$ ./kerl build R14B04 r14b04
$ ./kerl install r14b04 /opt/erlang/r14b04
$ . /opt/erlang/r14b04/activate
In the above example, kerl installs Erlang R14B04 to directory /opt/erlang/r14b04 and makes it default. For more information, please check kerl readme.
QUESTIONS??
You can either mail them to jesper.louis.andersen@gmail.com
or you
can come by on IRC #etorrent/freenode and ask.
Development
PATCHES
To submit patches, we have documentation in documentation/git.md
,
giving tips to patch submitters.
Setting up a development environment
When developing for etorrent, you might end up generating a new environment quite often. So ease the configuration, the build infrastructure support this.
- Create a file
rel/vars/etorrent-dev_vars.config
based upon the filerel/vars.config
. - run
make compile etorrent-dev
- run
make console
Notice that we -pa
add ../../apps/etorrent/ebin
so you can l(Mod) files
from the shell directly into the running system after having
recompiled them.
Documentation
Read the HACKING.md file in this directory. For how the git repository
is worked, see documentation/git.md
.
ISSUES
Either mail them to jesper.louis.andersen@gmail.com
(We are
currently lacking a mailing list) or use the issue tracker
Reading material for hacking Etorrent:
-
Protocol specification - BEP0003: This is the original protocol specification, tracked into the BEP process. It is worth reading because it explains the general overview and the precision with which the original protocol was written down.
-
Bittorrent Enhancement Process - BEP0000 The BEP process is an official process for adding extensions on top of the BitTorrent protocol. It allows implementors to mix and match the extensions making sense for their client and it allows people to discuss extensions publicly in a forum. It also provisions for the deprecation of certain features in the long run as they prove to be of less value.
-
wiki.theory.org An alternative description of the protocol. This description is in general much more detailed than the BEP structure. It is worth a read because it acts somewhat as a historic remark and a side channel. Note that there are some commentary on these pages which can be disputed quite a lot.