Open Charging Network Registry

Registry smart contract for OCN Node operator and OCPI party listings. For Ethereum-based networks.

Pre-amble

There are a few concepts which first need to be explained. The Registry smart contract works on Ethereum-based blockchains. That might be ganache if running a local development blockchain, or the pre-production or production chain of the Energy Web Foundation's blockchain. These chains use Etheruem's public-private key cryptography. In the OCN they are used to identify Node operators and OCPI parties on the Open Charging Network and can be generated in a variety of ways, for example by Metamask.

Signers and Spenders

The OCN Registry allows for two ways of adding and maintaining listings. It can be done directly, whereby a single keypair signs the registry data and sends a transaction to the blockchain network, paying for the transaction fee in the process. This is arguably simpler but requires each keypair to be funded. Alternatively, "raw" transactions can be used, whereby the registry data is signed by the data owner's keypair and sent to the blockchain network using a different, funded keypair.

Therefore, in "direct" transactions, the signer and spender are one, named just the "signer". In contrast, in raw transactions, the "signer" is the data owner, and the "spender" is the one paying for the transaction.

Node Operators and OCPI Parties

The principle behind the registry is that the nodes, comprising the Open Charging Network, need a way of discovering counterparties they are not directly connected to. This works in two stages: OCN Node operators (i.e. administrators) can list their node in the registry, which allows OCPI parties (i.e. Charge Point Operators or E-Mobility Service Providers) to link their services to a registered node.

Note that the registry listing must be done by the OCPI party before an OCN Node accepts their credentials registration, so that the OCN Node can ensure the party has correctly linked themselves to that node in the registry.

Example steps:

1. Operator signs a transaction stating they run the OCN Node on domain https://node.ocn.org. The address of their wallet (0x9bC1169Ca09555bf2721A5C9eC6D69c8073bfeB4), used to sign the transaction, now points to the domain name.

2. OCPI party signs a transaction stating they use the OCN Node of 0x9bC1169Ca09555bf2721A5C9eC6D69c8073bfeB4. The address of their wallet, (0x0B2E57DDB616175950e65dE47Ef3F5BA3bc29979) now points to the wallet address of their OCN Node operator.

3. OCPI party does the credentials registration handshake with the OCN Node at https://node.ocn.org.

4. Party is now able to send and receive OCPI requests from other OCPI parties on the network.

Usage

There are several ways to interact with the OCN Registry, including:

• CLI
• TypeScript Library
• Java Library

Command Line Interface

Getting started

Clone this repository or install the registry npm package:

Using this repository

git clone https://bitbucket.org/shareandcharge/ocn-registry.git
cd ocn-registry
npm install
npx ts-node src --help

Using the npm package

npm install -g @shareandcharge/registry
ocn-registry --help

Setting the signer

The private keys of the signer (and optionally spender) are needed for each transaction (modifying state of the contract). Contract calls (i.e. getting data) do not require this.

This can be done in two ways: environment variables or command line flags.

EXPORT SIGNER=0xbe367b774603c65850ee2cf479df809174f95cdb847483db2a6bcf1aad0fa5fd

If using a raw command, the spender is also required:

EXPORT SENDER=0x2f0810c5fc949c846ff64edb26b0b00ca28effaffb9ac867a7b9256c034fe849

Important: do not use these private keys outside of development! They were generated for this guide only.

Alternatively, flags allow setting the signer and spender for each command. Add --help to any command to get information about available flags.

Choosing the network

By default, the registry will look for a local ganache instance running on http://localhost:8544. This is the development chain which can be started with npm run ganache. This also provides 20 funded keypairs to play around with (they are generated from a mnemonic, so won't change between restarts). Each command can be run against additional networks on which the OCN Registry has been deployed. As of February 2020, this is only the Volta pre-production network of the Energy Web Chain. The CLI will connect to a remote Volta node (as detailed here) when the network flag is specified and volta is chosen.

Get an operator's node

To check the domain of a single node operator on the network, use:

ocn-registry get-node 0xEada1b2521115e07578DBD9595B52359E9900104

Where 0xEada1b2521115e07578DBD9595B52359E9900104 is the operator's keypair address.

To use the Volta network:

ocn-registry get-node 0xEada1b2521115e07578DBD9595B52359E9900104 --network=volta

Get all nodes

To return a list of all nodes and operators, use:

ocn-registry list-nodes

Listing a node

OCN Node operators can make their node visible on the network by adding it to the OCN Registry. Creating and updating a listing can be done using the same command:

ocn-registry set-node https://node.provider.net

Alternatively, using a raw transaction:

ocn-registry set-node-raw https://node.provider.net

Remember to set the signer AND spender for the raw transaction. If not using environment variables, set with the following flags:

ocn-registry set-node-raw https://node.provider.net
        --signer=0xbe367b774603c65850ee2cf479df809174f95cdb847483db2a6bcf1aad0fa5fd 
        --spender=0x2f0810c5fc949c846ff64edb26b0b00ca28effaffb9ac867a7b9256c034fe849

Type --help after any command for more information.

ocn-registry set-node-raw --help

De-listing a node

If an operator decides not to provide a node any longer, they can remove it from the registry:

ocn-registry delete-node

Or as a raw transaction:

ocn-registry delete-node-raw

Get party information

Check the registered information of a given party using their address or OCPI credentials (country_code and party_id):

ocn-registry get-party -a 0x0B2E57DDB616175950e65dE47Ef3F5BA3bc29979
ocn-registry get-party -c CH CPO

Get all parties

List all registered parties on the network:

ocn-registry list-parties

Listing a party

To list a party, the following information is required:

• country_code and party_id
• role
• OCN Node operator wallet address

The following commands can be used to both create and update the party information.

Scenario 1: party_id with single role

Using a direct transaction:

ocn-registry set-party -c CH CPO -r CPO -o 0x9bC1169Ca09555bf2721A5C9eC6D69c8073bfeB4

Using a raw transaction:

ocn-registry set-party-raw -c CH CPO -r CPO -o 0x9bC1169Ca09555bf2721A5C9eC6D69c8073bfeB4

Scenario 2: party_id with multiple roles

ocn-registry set-party -c CH ABC -r CPO EMSP -o 0x9bC1169Ca09555bf2721A5C9eC6D69c8073bfeB4

Scenario 3: platform with multiple roles under different party_ids

In this case, the platform must use different wallets for each party_id:

ocn-registry set-party -c CH CPO -r CPO -o 0x9bC1169Ca09555bf2721A5C9eC6D69c8073bfeB4 -s 0xd37f60f3a7c78a72d24e50b9105879c89d249e299699ba762d890276dea73fea
ocn-registry set-party -c CH MSP -r EMSP -o 0x9bC1169Ca09555bf2721A5C9eC6D69c8073bfeB4 -s 0x0bdea97cf8736a66f85283d7b0241b5cba51edd809a67af5e8971f441aa8e22b

Listing OCPI modules implemented by the party

In this opt-in feature, an OCPI party can list their module implementations, so that other parties on the network can learn which requests are supported. As the usual OCPI version endpoints cannot be used by counterparties, this provides a way for them to discover supported OCPI 2.2 modules.

Implementations are split into sender and receiver interfaces. For example, an EMSP may implement the command module's sender interface, and a CPO the receiver interface. Alternatively, a single party_id with both CPO and EMSP roles may implement both.

Note that as the purpose of this is to provide modules used typically used in peer-to-peer communication, not every module is available. The following modules can be listed: cdrs, chargingprofiles, commands, locations, sessions, tariffs, tokens.

Scenario 1: CPO or EMSP providing their implementations

Following typical OCPI implementations, a CPO could register their modules like so:

ocn-registry set-modules \
    --sender-interface cdrs locations session tariffs \
    --receiver-interface chargingprofiles commands tokens

Whereas an EMSP may register the following modules:

ocn-registry set-modules \
    --sender-interface commands tokens \
    --receiver-interface locations sessions tariffs

Scenario 2: CPO and EMSP providing combined implementations

In the case that a party_id implements multiple OCPI roles, both sets of interfaces can be listed. When sending a request to either interface, the OCN Node of the recipient will know which interface it should be forwarded to.

ocn-registry set-modules \ 
    --sender-interface commands cdrs locations \
    --receiver-interface commands cdrs locations

Updating modules is done by the same command and can also be used to remove all listed modules (by providing none):

ocn-registry set-modules 

Raw transactions can also be used:

ocn-registry set-modules-raw

De-listing a party

Use the following command to remove a party listing from the registry:

ocn-registry delete-party

And with raw transaction:

ocn-registry delete-party-raw

TypeScript Library

npm install @shareandcharge/registry

In your project source file, import the registry:

TypeScript:

import { Registry } from "@shareandcharge/registry"

JavaScript:

const Registry = require("@shareandcharge/registry").Registry

Then, instantiate the Registry class with the environment ("local" or "volta"). Optionally set the signer to gain access to write methods on the contract:

const registryReadOnly = new Registry("local")
console.log(registryReadOnly.mode)
// "r"

const registryReadWrite = new Registry("local", "0xbe367b774603c65850ee2cf479df809174f95cdb847483db2a6bcf1aad0fa5fd")
console.log(registryReadWrite.mode)
// "r+w"

And use the contract:

registryReadOnly.getAllNodes().then(console.log)

registryReadWrite.setNode("https://node.provider.net").then(console.log)

Java Library

TODO

Development

Clone and install dependencies:

git clone https://bitbucket.org/shareandcharge/ocn-registry.git
cd ocn-registry
npm install

Run Ganache for your local development blockchain:

npm run ganache

Ensure tests are working as expected:

npm test

Migrating contracts

Initial deployment of the smart contracts (STAGE defaults to "local" - see truffle.js for more options):

npm migrate --network={{STAGE}}

Publish new contract definitions:

node bin/publish.js {{STAGE}}

The contract definitions are now available to be used in ./contract.defs.{{STAGE}}.json.

Updating contract wrappers

The Java wrapper can be updated using web3j:

npm run compile
web3j truffle generate ./build/contracts/Registry.json -o ./java -p snc.openchargingnetwork.contracts

Publishing new versions

Build the TypeScript library:

npm run build

Bump the version number (see https://docs.npmjs.com/cli/version for more):

npm version patch 

Publish:

npm publish

Docker

You may also use Docker to aid development of other services using the registry. Simply run docker-compose up to start ganache and have the contracts deployed automatically. The registry contract will always have the same owner and address:

• Address: 0x345cA3e014Aaf5dcA488057592ee47305D9B3e10
• Owner: 0x627306090abaB3A6e1400e9345bC60c78a8BEf57

If you make changes to the contracts, run docker-compose --build. This will ensure that the above is true, giving you the same address.