CryptoIndex Home

CryptoIndex is a Ruby on Rails platform for compiling cryptocurrency indexes and allowing users to buy dynamically rebalanced portfolios. The product was never launched so its code has been open-sourced in case it proves a useful starting point for programmers attempting to solve similar problems in future.

• Features
• Installation
• Data Model
• Infrastructure
• Security Model
• Project Management
• Linting
• Testing
• Performance Testing
• Legal

Features

• calculate cryptocurrency index values based on pricing data the server gathers
• accept deposits from users in Ether
• assembles a portfolio of cryptocurrencies corresponding to the index for each user
• execute trades on Binance
• rebalance portfolios once a month
• super basic KYC (phone confirmation/crappy address confirmation)

Installation

Assumptions: You are on a Mac and using nvm.

• Install Bundler and Foreman:

  $ gem install bundler
  $ gem install foreman -v 0.84
  

• Run Bundler:

  $ bundle install
  

• Install Yarn:

  $ brew install yarn --without-node
  

• Download Yarn packages:

  $ yarn install
  

• Initialize the local database:

  $ rails db:setup
  

• Install Redis and configure to run at login:

  $ brew install redis
  $ brew services start redis
  

• Optional: Install Ganache CLI:

  $ yarn global add ganache-cli
  

• Run Foreman:

  $ foreman start
  

• Open localhost:3000 in your favorite browser.

Git Hooks

We store a pre-push Git hook in ./git-hooks. Install with:

$ cp ./git-hooks/pre-push .git/hooks/
$ chmod +x .git/hooks/pre-push

# Install dependency `ag` (The Silver Searcher)
$ brew install ag

Note: The pre-push Git hook does not run the RSpec system tests. You can run them by typing bin/rspec manually. Please make sure to do so periodically.

Blockchain Testing

In the development and test environments, our wallets are seeded with the mnemonic:

'nominee relief private cruise shoe pudding master spike gospel few creek hungry'

A handy external tool for verifying derived addresses, public keys, and private keys can be found here.

Sending Deposits

To send a deposit in the development environment, e.g., run:

Blockchains::Ethereum::Network.send_transaction(
  private_key: '11d0a1403641ae0758aec808d479ba39992fe7761d0086ae46cd4b5bbce7c2e5',
  from_address: '0x334670deb29fd28ea713c8c6565040a87c2b5217',
  to_address: '0xb6efbdd4515e63eb2080a83385748170209c1313',
  nonce: 0,
  value: 100
)

Note that in order to send a transaction from another address, you'll need to update the private_key as well as the from_address.

In this example, from_address refers to the first_user's Ethereum account from config/data/blockchains/ganache/accounts.csv, and to_address refers to the first deposit address generated by the system.

Rails Credentials

We maintain an unencrypted config/credentials.yml in addition to the encrypted config/credentials.yml.enc file. Please make sure that they always have the same structure and sequence of entries.

Merge Conflicts

Merge conflicts in the encrypted credentials file can be annoying.

The following workflow usually helps:

$ git checkout --theirs config/credentials.yml.enc
$ rails credentials:show | $EDITOR

$ git checkout --our config/credentials.yml.enc
$ rails credentials:edit

Then carefully compare the two versions and save a new version of the combined credentials file.

Data Model

Currencies

The Currency model represents a cryptocurrency.

Currencies are carefully curated and whitelisted as part of the config/currencies.csv file. Only whitelisted currencies are included in our indexes, traded on exchanges, and held within our storage systems.

Currencies have a trackable_at date.

They may also be rejected: In this case, the rejected_at date indicates the first timestamp the currency has been disregarded at. We reject currencies such as The DAO in order to protect users from harmful investments, and similarly exclude stablecoins and other assets that are not suitable long-term investments. Rejected currencies are neither tracked nor traded, and we sell off existing holdings of a to-be-rejected currency before the rejected_at date.

Valuations

The Valuation model represents the market value of a cryptocurrency at a specific timestamp.

A valuation is associated with one or more Valuation::Reading instances which provide the raw data from an industry source such as CoinMarketCap. It also has a Valuation::Indicator which adds further information such as the 24-hour moving averages for a number of its attributes.

Valuations form the basis of our cryptocurrency index allocations. By default, they are automatically created for the past month in development. Check out config.settings.bootstrap in development.rb to change the default behavior.

In order to create the valuations for all currencies for yesterday and today, run:

$ rails valuations:create

In order to create the valuations for all currencies on January 1st, 2018, run:

$ rails valuations:create[2018-01-01]

In order to create the valuations for all currencies for the entire month of January 2018, run:

$ rails valuations:create[2018-01-01,2018-01-31]

In order to scan all valuations gathered in 2018 for missing data, run:

$ rails valuations:validate[2018-01-01,2018-12-31]

In order to automatically try and create missing valuations, you can run the validation with the repair=true option:

$ rails valuations:validate[2018-01-01,2018-12-31,repair=true]

Valuations readings are immutable.

Valuations are immutable once an index has been allocated at that timestamp.

Indexes

The Index model represents a weighted and capped cryptocurrency index.

Indexes are the lifeblood of CryptoIndex's investment platform. We enable investors to invest in the whole market with a long-term perspective. Indexes have a fixed number_of_components. They also have a minimum_component_weight in order to make sure that a certain minimum position of each currency is held and a maximum_component_weight in order to make sure that no single currency dominates the overall index.

An index is associated with a single Index::Allocation instance for each timestamp which in turn represents a collection of Index::Component instances. The latter represent the currencies included in the index together with their respective weight. The weights always add up to 1.0 for every allocation.

An index allocation's value is defined as the sum of the market capitalizations of each component by the divisor of the index. The divisor is defined as the sum of the market capitalizations of each component of the index's genesis allocation on January 1st, 2017.

In order to create the allocations for all indexes for yesterday and today, run:

$ rails allocations:create

In order to create the allocations for all indexes on January 1st, 2018, run:

$ rails allocations:create[2018-01-01]

In order to create the allocations for all currencies for the entire month of January 2018, run:

$ rails allocations:create[2018-01-01,2018-01-31]

Index allocations and their components are immutable.

Linting

We use RuboCop for Ruby, ESLint for JavaScript, ShellCheck for shell scripts, and Stylelint for Sass.

Setup

• rubocop is part of the :development group in Gemfile.
• shellcheck can be installed using $ brew install shellcheck.
• eslint and stylelint are part of the devDependencies in package.json.

Rule Sets

• RuboCop: .rubocop.yml
• ESLint: .eslintrc and .eslintignore
• Stylelint: stylelint.config.js

Linting from the Command Line

We enforce linting via Git hooks, although it's possible to run them individually:

Ruby:

$ bin/rubocop
Inspecting X files
.....................................

X files inspected, no offenses detected
$

JavaScript:

$ bin/eslint
$

Shell scripts:

$ bin/shellcheck
$

Sass:

$ bin/stylelint
$

Testing

Ruby tests should generally be run with bin/rspec. This wrapper adds blockchain support to the tests. Individual tests not tagged with mining can be run with the unwrapped rspec command and will execute more quickly.

Code Coverage

By default, the generation of code coverage is switched off. To generate a report, run the tests with:

$ COVERAGE=true bin/rspec

The results can then be viewed with:

open coverage/index.html

Note: This only reports on code coverage in Ruby files. No information is given about code coverage with respect to our front-end.

Fixtures

Generation

Our fixture files are generated dynamically with the fixture_builder gem, which is configured via a file of the same name. You can regenerate the fixtures with:

$ rails db:fixtures:regenerate RAILS_ENV=test

Goals

1. Minimize the amount of data. This is done by reusing the same currency symbols where possible and by minimizing the number of timestamps we cover with data (e.g. for valuations, compositions, etc.). When writing an integration test, it's generally necessary to freeze time to something like Fixtures::DEFAULT_TIMESTAMP or some other timestamp known to have comprehensive data.

2. Have deterministic pricing data that can be tested against. These are contained in the file spec/support/fixtures.rb The main purpose of this is to allow us to write tests in terms of invariant prices. Doing so insulates the integration tests from breaking when we modify the fixtures.

# bad (hard-coded style)
expect(btc_market_cap).to eq(8200.04)

# good (invariant style)
expect(btc_market_cap).to eq(Fixtures.market_cap_for('BTC', Time.now))

3. Have users with intelligently named email addresses. We choose names according to the actions users have taken in the system (and the corresponding fixtures available for them), e.g. [email protected], [email protected].

4. Tell a somewhat realistic story with the data. For example, pricing data and the contents of the indexes should roughly match the real world at the testing timestamps.

5. Avoid the need to mock ActiveRecord in integration tests.

Tags

• qa - Tests that, while important for quality assurance (QA), do not need to be run frequently.

• ethereum - Tests that require mining on the Ethereum blockchain.

Quirks

The application is highly dependent on time, therefore freezing of time needs to be micro-managed throughout the tests.

Be aware of:

1. Currency availability via trackable_at, rejected_at, etc.

2. Calls to Time.now (e.g. in Compositions::Create) that cut off data creation

3. Any time scopes that scan for before_x or after_x

4. Qny wait periods (e.g. WAIT_INTERVAL, REFERENCE_INTERVAL, RECENT_INTERVAL)

5. Expectations that pricing data is available at certain timestamps (e.g. Valuation::Indicator::MINIMUM_NUMBER_OF_PRIOR_VALUATIONS)

6. Time-dependent levying of CryptoIndex fees (pre- vs. post-LAUNCH_DATE)

Performance Testing

RAM and CPU Usage (development)

First enable caching with

$ rails dev:cache

Testing for a Memory Leak

Run the following command, gradually increasing the TEST_COUNT up to however many thousands are needed. A file will be generated in the /tmp directory detailing memory usage over time.

In this example, the path /currencies will be hit:

$ TEST_COUNT=10 DISABLE_SPRING=1 PATH_TO_HIT=/currencies RAILS_ENV=development bundle exec derailed exec perf:mem_over_time

Testing Object Generation in Memory

Again, testing the path /currencies:

$ TEST_COUNT=10 PATH_TO_HIT=/currencies RAILS_ENV=development bundle exec derailed exec perf:objects

Testing CPU Performance

This command tells you which methods were consuming the most CPU resources:

TEST_COUNT=5 PATH_TO_HIT=/currencies RAILS_ENV=development bundle exec derailed exec perf:stackprof

Testing Memory Required by Gems

This command need only be run with TEST_COUNT=1:

$ RAILS_ENV=development bundle exec derailed bundle:mem

Postgres (production)

Most of this section assumes you have enabled the Heroku pg-extras plugin.

$ heroku plugins:install heroku-pg-extras

Index Hit Ratio

Measures how often Postgres can use indexes as opposed to having to scan the entire table, an incredibly slow operation:

$ heroku pg:index-usage

Cache Hit Ratio

Measures how often Postgres has the desired table data/indexes/query execution plans etc. cached in RAM, as opposed to having to hit the hard drive. Anything below 0.99 is generally seen to be indicative of insufficient RAM:

$ heroku pg:cache-hit

Locks

Describes the locks currently granted. Helps to debug deadlock situations:

$ heroku pg:locks

Most Time-Consuming Queries

Lists the top ten most time-consuming commands and the number of times they were called:

$ heroku pg:outliers

Legal

MIT License

Copyright 2018 Jack Kinsella

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Additional warnings

• You are free to use the CryptoIndex code under the MIT license, but not necessarily any libraries we include. It is therefore your responsibility to ascertain whether any licensing restrictions apply to the ruby/node/other libraries used.

• The code is provided for non-production demo purposes. It is your responsibility to check for legality issues with regards to deploying in a real system.