GSN Kit - Transactions related to oz cli questions (Learning)

grog · January 8, 2020, 5:15pm

I’m trying to understand exactly what’s going on when playing with gsn kit with oz create Counter and npx oz-gsn fund-recipient --recipient 0x6F43ad249A11B57C66da54453be8226a722f66B4 regarding transaction’s “point of view”.

oz create Counter creates 3 tx:

the first one create Counter logic’s contract
the second creates the proxyAdmin contract
the third creates the Counter-proxy contract

So far so good, but I did not figure it out how call/read the proxyAdmin. I thought I could do so via oz call or oz send-tx but only Counter looks accessible via these command (or the proxy’s counter more precisely). I found oz set-admin but what if I wanted to do this manually ? What if I wanted to read the current value of admin (address) ?
Is this behaviour normal ?
On top of that, on the build directory there is no ProxyAdmin.json which means no abi in order to get the instance on a truffle console so… I’m wondering how the contract has been deployed in the first place…

npx oz-gsn fund-recipient --recipient 0x6F43ad249A11B57C66da54453be8226a722f66B4 creates also 3 txs:

account[0] send 0.42 eth to an “unknown” address (A)
(A) creates the Relayhub contract
account[0] sent by default 1 eth to the RelayHub

Could you please explain what happening here ?
From my understanding:

the first just “load” an openzeppelin’s EOA called “deployer” (https://github.com/OpenZeppelin/openzeppelin-gsn-helpers/blob/master/src/data.js)
the second just use the deployer to creates the RelayHub contract, okay
but the third one…I’m not sure.

I dig a bit here and there and I think a got some pieces of the cake but not the whole, especially regarding the third transaction.
Initially I thought any Recipient would keep some eth “inside” so that it would pay a successfull relayer’s action. But the funds actually go to the RelayHub contract which I guess act a little bit as an escrow in a sense that, it is is responsability to trigger the “payment/reward” on behalf of the recipient, so that guaranteeing both parties.

If it’s correct, how are we suppose to fund one recipient “normally” ? Using the command line oz-gsn fund-recipient or manually with the depositFor fonction ?
Is it possible to achieve a logic in which a relayer get paid with a portion of an ERC20 transfer (the meta tx relayed) ?

abcoathup · January 9, 2020, 6:41am

Hi @grog,

We can interact with the ProxyAdmin contract

github.com

OpenZeppelin/openzeppelin-sdk/blob/master/packages/lib/contracts/upgradeability/ProxyAdmin.sol#L43


      
            (bool success, bytes memory returndata) = address(proxy).staticcall(hex"f851a440");
            require(success);
            return abi.decode(returndata, (address));
          }
          
          /**
           * @dev Changes the admin of a proxy.
           * @param proxy Proxy to change admin.
           * @param newAdmin Address to transfer proxy administration to.
           */
          function changeProxyAdmin(AdminUpgradeabilityProxy proxy, address newAdmin) public onlyOwner {
            proxy.changeAdmin(newAdmin);
          }
          
          /**
           * @dev Upgrades a proxy to the newest implementation of a contract.
           * @param proxy Proxy to be upgraded.
           * @param implementation the address of the Implementation.
           */
          function upgrade(AdminUpgradeabilityProxy proxy, address implementation) public onlyOwner {
            proxy.upgradeTo(implementation);

There isn't currently an OpenZeppelin CLI command to get the current value of the admin address.
We can see the ProxyAdmin address in <network.json> in the .openzeppelin directory.

Yes, this is how it currently works.

The json for @openzeppelin/upgrades can be found in the following directory: .node_modules/@openzeppelin/upgrades/build/contracts

The third transaction is funding the recipient contract with 1 Ether in the RelayHub (calling depositFor.

Deposits Ether for a contract, so that it can receive (and pay for) relayed transactions.

github.com

OpenZeppelin/openzeppelin-gsn-helpers/blob/master/src/fund.js#L27


      
            // Ensure relayHub is deployed on the local network
            if (options.relayHubAddress.toLowerCase() === data.relayHub.address.toLowerCase()) {
              await deployRelayHub(web3, options);
            }
            const relayHub = getRelayHub(web3, options.relayHubAddress);
          
            const targetAmount = new web3.utils.BN(options.amount);
            const currentBalance = new web3.utils.BN(await relayHub.methods.balanceOf(options.recipient).call());
            if (currentBalance.lt(targetAmount)) {
              const value = targetAmount.sub(currentBalance);
              await relayHub.methods.depositFor(options.recipient).send({ value, from: options.from });
              return targetAmount;
            } else {
              return currentBalance;
            }
          }
          
          module.exports = {
            fundRecipient,
          };

We fund the recipient contract using the GSN Dapp Tool
Open https://gsn.openzeppelin.com/recipients in a browser with MetaMask (or other web3 provider) and deposit for the recipient contract.

See the following guide for: Using Gas Station Network starter kit on a public testnet

Let me know if you need more information.

abcoathup · January 9, 2020, 11:47pm

Hi @grog,

I realized that I had missed a question.

Not currently. The RelayHub uses Ether for paying relayers.

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GSN Kit - Transactions related to oz cli questions (Learning)

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