jamii

sudo apt-get install build-essential python python-dev erlang erlang-dev python-django python-flup python-sphinx libcmph-dev git-core emacs

git clone git://github.com/tuulos/disco.git
cd disco
make
make install
cd lib
python setup.py build
python setup.py install
cd ../contrib/discodex

jamii

make
make install
make install-core
make install-discodb
make install-discodex

jamii

root@li317-243:~/disco# discodex start
-bash: discodex: command not found
root@li317-243:~/disco# bin/discodex start
[Errno 2] No such file or directory
root@li317-243:~/disco# bin/discodex start -v

discodex settings are:

                DISCODEX_DISCO_MASTER = disco://localhost
		DISCODEX_DISCO_PREFIX = _discodex

jamii

root@li317-243:~/disco# bin/discodex start -v

discodex settings are:

                DISCODEX_DISCO_MASTER = disco://localhost
		DISCODEX_DISCO_PREFIX = _discodex
		DISCODEX_ETC_DIR = /usr/local/lib/discodex/etc
		DISCODEX_HOME = /usr/local/lib/discodex
		DISCODEX_HTTP_HOST = localhost
		DISCODEX_HTTP_PORT = 8080

jamii

root@li315-143:~# disco jobs
ExtractFeatures@51d:371d4:4cf64
BuildHistograms@51d:369b8:838a8
root@li315-143:~# ls /usr/local/var/disco/data/*/*/*
/usr/local/var/disco/data/_disco_8989/35/BuildHistograms@51d:369b8:838a8:
events  jobfile

/usr/local/var/disco/data/_disco_8989/c3/ExtractFeatures@51d:371d4:4cf64:
events  jobfile

jamii

# DISCO_GC_AFTER = 5
rm -rf /usr/local/var/disco/data/*/*
disco debug
  temp_gc:start_link(whereis(disco_server)). % leave running
ipython
  import poc
  poc.build() # starts several jobs and purges when finished
# wait 10 minutes
jamie@alien:~/springer-analytics$ ls /usr/local/var/disco/data/*/*/*
/usr/local/var/disco/data/alien/01/CreateDB@51d:5d429:6b2d7:

jamii

in_journal() ->
    receive
        {Seq, Event} ->
            transaction_manager ! {Seq, Event},
            write({Seq, Event}),
            sync(),
            out_journal ! {journaled, Seq}
    end.

% in cpp or ocaml

jamii

let recover_with recover f =
  try
    f ()
  with Invalid_transition _ as exc ->
    recover exc;
    raise exc

let unrecoverable f =
  try
    f ()

jamii

Entities

An entity is an account, order, market, contract, deposit or withdrawal. Every entity has a unique uid. Once created entities are never deleted.

Error handling conventions

We distinguish between recoverable errors and failures.

Recoverable errors are exceptions of type Invalid_transition. If this exception reaches the top level then piston will return an rpc error and continue processing. Any other exceptions will cause piston to die. Deepred will then mark the offending event as unprocessable and replay from a snapshot.

jamii

(ns mechanical-sympathiser.core
  (:require [mechanical-sympathiser.sound :as sound]
            [mechanical-sympathiser.system :as system]
            overtone.core)
  (:import (java.util Timer TimerTask)))

(def timer (new Timer))

(defn poll [period poll-fn]
  (let [task (proxy [TimerTask] []