The Syscoin Price Peg Server is a NodeJS server application for maintaining a Syscoin "Alias Peg" on the the Syscoin network's blockchain. An Alias peg provides information to the network on how many Syscoins are needed to equal 1 unit of any other currency supported by the peg.

The peg server uses data from multiple sources to derives the necessary values to convert values between various currencies. Fixer.io is used for all fiat currency conversion information, Coinbase is used for all BTC/USD conversion information, and a mix of Poloniex and Bittrex are used for all other blockchain currency information. The server watches each configured currency pair independently and when any one currency exchange rate moves outside the configured threshold the updated values are writted to the peg-alias on the Syscoin blockchain.

Syscoin Price Peg Server installation requires NPM and Node 7+.

Note: Prior to setup make sure you have the latest versions of the required tools using the commands:

• GIT: sudo apt-get install git
• NodeJS/NPM
  • curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -
  • sudo apt-get install -y nodejs

1. If installing from source first clone the repository using git clone https://github.com/syscoin/pricepeg.git.
2. Install the required dependencies using npm install.
3. This guide assumes you have already installed the latest Syscoin wallet and created a Syscoin.conf file with the required parameters to enable its JSONRPC server functionality.
4. The server comes with a default config.ini file which controls all aspects of the server, including which currencies it supports. For more information please refer to the configuration section.
5. Update the configuration file to reflect the Alias you with to use as a peg and the currencies you wish to support. You MUST create the peg alias on the Syscoin network with a public value of {"rates":[]} BEFORE attempting to run Price Peg Server to manage it! The wallet responsible for maintaining the peg Alias must also have a minimal balance to support transaction fees associated with the aliasupdate operation (50-100 SYS per year recommended).

The full list of supported currencies can be found in src/common.ts: supportedCurrencies or in the table at the bottom of this page.

The Price Peg Server must be run as a daemon. There are two optons for this:

• (Recommended) Install pm2 for better running and monitoring of the server in daemon mode.
  1. Install pm2 globall using sudo npm install -g pm2.
  2. Ensure pm2 is updated- pm2 update.
  3. Change to the Syscoin Price Peg Server directory using cd pricepeg. Run the server in daemon mode using pm2 start dist/server.js $CONFIG --name "pegserver" (may need permission).
  4. (Optional) You can now use pm2's tooling for insights on how many resources the Peg Server is using and even launch it in multiprocess or clustered mode.
• If you use the screen application you can start the server by simply running screen npm run start. Make sure to detach from the screen without terminating it!

The Syscoin Price Peg Server can easily be reconfigured with zero coding knowledge. Below are the configuration properties and options. The default configuration file can also be used as a reference.

We've also included some sample configurations to further illustrate how to customize the Syscoin Price Peg Server:

• Sample Config #1 DOGE/USD Peg w/ mods
• Sample Config #2 BTC/XMR/ZEC/ETH Peg w/ mods

IMPORTANT NOTE: Many properties that are typically required are marked as optional in the above table because the Syscoin Price Peg server has been developed in a way to provide all required values, in the form of their default values if the operator fails to override them (with the exception of CurrencyConfig. The server also has rudimentary configuration file validation- in situations where the server fails to start please review the output in the debugLogFilename for information on what the issues are with the configuration file.

Syscoin Price Peg Server is controlled through config.ini which uses the INI configuration file format. Below are some example configurations, for more info or questions please create an issue or ask in the Syscoin Slack.

• Support DOGE and USD
• Use peg-alias of "doge.peg"
• Limit to 3 updates per period
• Change update period to 3 days rather than the default 1hr
• Change update threshold to 1% rather than default 5%
• Change the auth info for server

;BASIC CONFIG
;maximum number of peg updates that will be allowed to occur in a single period
maxUpdatesPerPeriod = 3

;defintion of the duration of a single period in seconds
updatePeriod = 259200

;percentage at which an update is attempted, if value of peg fluctuates +/- this range
updateThresholdPercentage = 0.01

rpcuser = secretuser
rpcpassword = secretpassword
pegalias = doge.peg
pegalias_aliaspeg = doge.peg

;MODIFY BELOW SECTION TO CHANGE CURRENCY SUPPORT
[currencies.USD]
isFiat = true
escrowFee = 0.01
precision = 2

[currencies.BTC]
isFiat = false
dataSources = Poloniex, Bittrex
escrowFee = 0.01
fee = 75
precision = 8

• Support XMR, ZCash, BTC, and ETH
• Use peg-alias of "multicrypto.peg"
• Change update threshold to 10% rather than default 5%
• Change the auth info for server
• Change LogLevel config
• Change log file name

;BASIC CONFIG
;percentage at which an update is attempted, if value of peg fluctuates +/- this range
updateThresholdPercentage = 0.1
debugLogFilename = mypeg.log

rpcuser = secretuser
rpcpassword = secretpassword
pegalias = multicrypto.peg
pegalias_aliaspeg = multicrypto.peg

[logLevel]
logNetworkEvents = true
logBlockchainEvents = false
logPriceCheckEvents = true
logUpdateLoggingEvents = false

;MODIFY BELOW SECTION TO CHANGE CURRENCY SUPPORT
[currencies.BTC]
isFiat = false
dataSources = Poloniex, Bittrex
escrowFee = 0.01
fee = 75
precision = 8

[currencies.XMR]
isFiat = false
dataSources = Poloniex
escrowFee = 0.05
fee = 100
precision = 8

[currencies.ZEC]
isFiat = false
dataSources = Poloniex, Bittrex
escrowFee = 0.05
fee = 75
precision = 5

[currencies.ETH]
isFiat = false
dataSources = Poloniex, Bittrex
escrowFee = 0.1
fee = 200
precision = 5

Syscoin Price Peg Server is built using Typescript and ES6. Developers are encouraged to extend and enhance the native functionality, or add more currency support. Devs will need to work in the native Typescript files then transpile the code for distribution. The only command needed to rebuild code after changes is npm run build to rebuild the source and all resources to dist.

We encourage community contributon! If you wish to contribute please issue a pull request with your changes, the team will review and merge or provide feedback. All development should happen in the /src folder. All new files should be Typescript, using ES6 JS syntax.