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The elixir-omg repository contains OMG Network's Elixir implementation of Plasma and forms the basis for the OMG Network.

Build Status Coverage Status

IMPORTANT NOTICE: Heavily WIP, expect anything

Table of Contents

Getting Started

A public testnet for the OMG Network is coming soon. However, if you are brave and want to test being a Plasma chain operator, read on!

Service start up using Docker Compose

This is the recommended method of starting the blockchain services, with the auxiliary services automatically provisioned through Docker.

Before attempting the start up please ensure that you are not running any services that are listening on the following TCP ports: 9656, 7434, 7534, 5000, 8545, 5432, 5433. All commands should be run from the root of the repo.

To bring the entire system up you will first need to bring in the compatible Geth snapshot of plasma contracts:

make init_test

It creates a file ./localchain_contract_addresses.env. It is required to have this file in current directory for running any docker-compose command.

docker-compose up

To bring only specific services up (eg: the childchain service, geth, etc...):

docker-compose up childchain geth ...

(Note: This will also bring up any services childchain depends on.)

To run a Watcher only, first make sure you sent an ENV variable called with INFURA_API_KEY with your api key and then run:

docker-compose -f docker-compose-watcher.yml up

Troubleshooting Docker

You can view the running containers via docker ps

If service start up is unsuccessful, containers can be left hanging which impacts the start of services on the future attempts of docker-compose up. You can stop all running containers via docker kill $(docker ps -q).

If the blockchain services are not already present on the host, docker-compose will attempt to pull the latest build coming from master. If you want Docker to use the latest commit from elixir-omg you can trigger a fresh build by building all three services with make docker-childchain, make docker-watcher and make docker-watcher_info.

Install on a Linux host

Follow the guide to install the Child Chain server, Watcher and Watcher Info.

Installing Plasma contract snapshots

To pull in the compatible snapshot for Geth:

make init_test

Testing & development

Docker building of source code and dependencies used to directly use common mix folders like _build and deps. To support workflows that switch between bare metal and Docker containers we've introduced _build_docker and deps_docker folders:

sudo rm -rf _build_docker
sudo rm -rf deps_docker

mkdir _build_docker && chmod 777 _build_docker
mkdir deps_docker && chmod 777 deps_docker

Pull in the compatible Plasma contracts snapshot:

make init_test

You can setup the docker environment to run testing and development tasks:

docker-compose -f docker-compose.yml -f -f docker-compose.datadog.yml run --rm --entrypoint bash elixir-omg

Once the shell has loaded, you can continue and run additional tasks.

Get the necessary dependencies for building:

cd app && mix deps.get

Quick test (no integration tests):

mix test

Longer-running integration tests (requires compiling contracts):

mix test   --only integration

For other kinds of checks, refer to the CI/CD pipeline ( or build steps (

To run a development iex REPL with all code loaded:

MIX_ENV=test iex -S mix run --no-start

Running integration cabbage tests

Integration tests are written using the cabbage library and they are located in a separated repo - specs. This repo is added to elixir-omg as a git submodule. So to fetch them run:

git submodule init
git submodule update --remote

Create a directory for geth:

mkdir data && chmod 777 data

Make services:

make docker-watcher
make docker-watcher_info

Start geth and postgres:

cd priv/cabbage
make start_daemon_services-2

If the above command fails with the message similar to:

Creating network "omisego_chain_net" with driver "bridge"
ERROR: Pool overlaps with other one on this address space

try the following remedy and retry:

make stop_daemon_services
rm -rf ../../data/*
docker network prune

Build the integration tests project and run tests:

cd priv/cabbage
make install
make generate_api_code
mix deps.get
mix test

Running reorg cabbage tests

Reorg tests test different assumptions against chain reorgs. They also use the same submodule as regular integration cabbage tests.

Fetch submodule:

git submodule init
git submodule update --remote

Create a directory for geth nodes:

mkdir data1 && chmod 777 data1 && mkdir data2 && chmod 777 data2 && mkdir data && chmod 777 data

Make services:

make docker-watcher
make docker-watcher_info

Start geth nodes and postgres:

cd priv/cabbage
make start_daemon_services_reorg-2

Build the integration tests project and run reorg tests:

cd priv/cabbage
make install
make generate_api_code
mix deps.get
REORG=true mix test --only reorg

Working with API Spec's

This repo contains gh-pages branch intended to host Swagger-based API specification. Branch gh-pages is totally diseparated from other development branches and contains just Slate generated page's files.

See gh-pages README for more details.

More details about the design and architecture

Details about the repository, code, architecture and design decisions are available here.