robinagist/ezo

Ethereum Oracle and Offchain Development Toolset

ezo

Quickly Build Oracles and Event Responders on Ethereum using Python!

(13 June 2018) - now in alpha!

ezo (pronounced eh-zoh) makes Ethereum oracle development a snap. Developed in Python, ezo permits compiling and deploying contracts, and generating handler scaffolding that allows the fast development of off-chain data sources which respond to contract events.

Inspired by AWS toolsets, such as Serverless and Gordon, ezo allows for multiple deployment targets. Start out testing with Ganache on your local machine, later move to the test net and then the mainnet, by simply specifying the target at deployment time.

v 0.1a Features

• build oracles from the command line. removes the tedium from developing oracles and other off-chain contract event responders for Ethereum
• compile and deploy to multiple networks
• generates handlers in Python, for easy customization
• listen for, and respond to multiple events on multiple contracts
• Web3 1.0 using Web3.py
• compiles Solidity and (soon) Vyper contracts
• choose between IPC, WebSockets or HTTPS
• built-in Ethereum test client. Start ezo and bring up a second terminal to run contracts that kick off events.
• asychronous, single-threaded. no multiprocess witchcraft to deal with.

coming in version 1.0 - decentralized Ezo on Tendermint!!

ezo test client running against another instance of ezo in oracle mode

NOTE: Account management and transaction signing in the next alpha release. The Web3.py middleware layer for signing transactions transparently is still in testing. In the meantime, use your account addresses with your local node accounts, or Ganache accounts.

Install and Make A Project!!!

Build an Ethereum Oracle in 10 Minutes with Ezo and Python

To get up fast, the ezo comes preconfigured for running on Ganache GUI. Use it, and you won't have to mess with configuration right now. Just use the test target (more on that later).

ezo -- the first five minutes

0. Install dependencies:

   • Python 3.6
   • LevelDB.
   • Virtualenv
   • solc Solidity compiler

1. create Virtualenv and start

2. Install ezo with

   pip install ezo

3. create the ezo project with

   ezo create project <project name>

   Put in any name you like. We'll use MyEzo:

   ezo create project MyEzo

   Then cd into the project directory.

4. now, compile one of the test Solidity contracts (contract1.sol and contract2.sol):

   ezo compile contract1.sol

5. The name of the sample contract is TemperatureOracle.
   We'll create the handlers for it, and register to events:

   ezo gen handlers TemperatureOracle

   (if you look in the handlers subdirectory, you'll see a temperature_oracle directory, containing two Python handlers that are ready for code.)

6. Back in the project directory, we want to see our contract.

   ezo view contracts

   will show us our compiled contract.

7. With Ganache GUI running on port 7545, we'll deploy our contract. In ezo.conf, Ganache is already configured as the test target with a default Ganache account, using HTTPS, so we're ready to go.

   ezo deploy TemperatureOracle --target=test

8. Let's look at our deployed contract with

   ezo view deploys.

   We should see our contract there.

9. ezo is ready to start listening for the two events on the TemperatureOracle:

   ezo start TemperatureOracle --target=test

Now, ezo's built-in test client

1. With ezo running, open another terminal window and navigate to the project's base directory

2. start up Virtualenv

3. We're going to send a transaction to the TemperatureOracle's request method. It has no parameters, so we'll just pass an empty list. Sending the transaction fires an event that will show up as received in the ezo oracle terminal:

   ezo send tx TemperatureOracle request [] --target=test

4. You should see an event show up in the other terminal display, while the test client screen should fill up with transaction data (see image above).

Now, you can customize the oracle with Python code in just the handler. There is code to help you quickly wire up event responses.

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Check out the Wiki for more information

thank you

ezo is built using Python 3.6, the Cement CLI Framework and Web3.py, for use on any Ethereum blockchain network. Contract and deployment state is maintained in LevelDB. It makes use of solc, the Solidity compiler, and soon the Vyper compiler. To the folks that built those tools, and to the others who both necessitated the need for things such as ezo, and who also provided the pieces of the puzzle that made the project happen: thank you. ezo is dedicated to you, the open source community. You move the world forward.