Deploy on Arbitrum Testnets

[guidiaz]

https://developer.arbitrum.io/intro/

[guidiaz]

The fact that multiple chains can run in parallel is a crucial perk to off-chain scaling technology. Currently, on Ethereum mainnet, there are 2 Arbitrum chains: one Arbitrum Rollup chain, called "Arbitrum One," and one AnyTrust chain, called "Nova"; users and developers can pick whatever suits their security / transaction cost needs.

[guidiaz]

An Arbitrum AnyTrust chain doesn’t have the same decentralization / trustlessness / permissionless security guarantees of a Rollup chain, and thus can offer lower fees. Rollup and AnyTrust are similar in many ways, though have one key difference: whereas in Rollup, all data is posted on L1 (which allows anyone to permissionless join as a validator), in AnyTrust, data is managed off-chain. In the case of a challenge, an AnyTrust chain reverts back to “rollup mode”; the security assumption here is that at least 2 of the committee members are honest (i.e., they will provide the data when it’s necessary). Keeping the data off-chain in the happy/common case means the system can charge the user significantly lower fees. For applications that require high transaction throughput and don’t require the full decentralization that rollups provide, AnyTrust could be a sensible tradeoff.

[guidiaz]

GD: for the time being, we'll just deploy on Arbitrum One Testnet, until some specific support is requested for Arbitrum Nova.

[guidiaz]

Arbitrum/Ethereum Differences:

• Time in L2 is tricky; the timing assumptions one is used to making about L1 blocks don't exactly carry over into the timing of Arbitrum blocks.
• Arbitrum's L2 block hashes should not be relied on as a secure source of randomness.
• The L2 fees an Arbitrum transaction pays essentially work identically to gas fees on Ethereum. Arbitrum transactions must also, however, pay an L1-fee component to cover the cost of their calldata.
• Arbitrum transaction receipts include two additional fields: l1BlockNumber, gasUdedForL1.

[guidiaz]

Block numbers and time:

• Arbitrum blocks are assigned their own L2 block numbers, distinct from Ethereum's L1 block numbers.
• But,,,,,,,, accessing block numbers within an Arbitrum smart contract (i.e., block.number in Solidity) will return a value close to (but not necessarily exactly) the L1 block number at which the Sequencer received the transaction.
• Arbitrum blocks have their own block numbers, starting at 0 at the Arbitrum genesis block and updating sequentially.
• A client that queries an Arbitrum node's RPC interface (for, ie., transaction receipts) will receive the transaction's Arbitrum block number as the standard block number field. The L1 block number will also be included in the added l1BlockNumber field.

[guidiaz]

Nitro Goerli Rollup Testnet: This testnet (421613) uses the Nitro rollup tech stack; it is expected to be the primary, stable Arbitrum testnet moving forward. Users can now use Alchemy, Infura, and QuickNode to interact with the Arbitrum One.

[guidiaz]

Let's go for Arbitrum Nitro Goerli deployment, then.

[guidiaz]

Bridging 0.5 GoerliETH to 0.5 AGOR in Arbitrum Nitro Goerli:

• L1 tx: https://goerli.etherscan.io/tx/0xc2613cc10de0425e8f3aafc2856ea884aa4e19153826d944e853314366714c6c
• L2 tx: https://goerli.arbiscan.io/tx/0x116afaedf0d895bf6ee41fd4758cc01653f4e936b568700a9eb9088f38f01d6f

[guidiaz]

Arbitrum Nitro Goerli:

• Chain id: 421613
• RPC: https://goerli-rollup.arbitrum.io/rpc
• Explorer: https://goerli.arbiscan.io, https://goerli-rollup-explorer.arbitrum.io

[guidiaz]

Goerli faucet can be used on ETH/L1, and then bridge those to ARB/ETH/L2 via the Arbitrum Bridge dapp:

• https://bridge.arbitrum.io/

(works the same of all Arbitrum chains, as long as they're available on preferred web wallet)

[aesedepece]

Arbitrum Nitro Goerli:

* Chain id: 421613

* RPC: https://goerli-rollup.arbitrum.io/rpc

* Explorer: https://goerli.arbiscan.io, https://goerli-rollup-explorer.arbitrum.io

I sent an Infura URL to you over Telegram, just in case you want to use that!

[guidiaz]

Bridging GoerliETH from L1 to L2 takes like 15 minutes.

[guidiaz]

Script "arbitrum:goerli" added to Web3 RPC gateway. It works by settings

ETHERS_ESTIMATE_GAS_PRICE=true
ETHERS_ESTIMATE_GAS_LIMIT=true
ETHERS_GAS_LIMIT_FACTOR=1.25
ETHERS_MOCK_FILTERS=true

[guidiaz]

Btw, there's also a Twitter faucet for Nitro Goerli linked from the Arbitrum Bridge dapp. It provides like 0,001 AGOR in L2, after a few minutes.

[guidiaz]

Deployed and verified contracts in Arbitrum Nitro Goerli:

• Witnet Solidity Bridge:

  • WitnetDecoderLib: 0x9Ef886Df202100FFc1b38388b3591e0031E53045
  • WitnetParserLib: 0x7d0a71D7D797b7b2637F682e4cB47f66602e59F3
  • WitnetProxy: 0xa6a6b2cBE9Ce5B8fF94729F1eC402efc5042AbBF
  • WitnetRequestBoardTrustableDefault: 0x17c7b4E454689EF181dE1FfA6eC59b3D146344bD

• Witnet use cases:

  • WitnetPriceRouter: 0xAafb2D27E2E0f83dcE501a2879aaD710ec377403
  • WitnetRandomness: 0xB0C5d40A7658b2ab28360aFa6eB5bAeb2fFe86c3

• Witnet price feeds:

  • Price-ETH/USD-6: 0xA349fE7Ac24EEF338D14E3d3A32AdB2bAda16A11

[guidiaz]

Related PRs:

• https://github.com/witnet/witnet-solidity-bridge/pull/296
• https://github.com/witnet/witnet-price-feeds/pull/145
• https://github.com/witnet/data-feeds-explorer/pull/271

[guidiaz]

Both evm accounts for pollers and bridges have been authorized.

[guidiaz]

Create new bridge stack in bootstrap host, named as "bridgearbitrumgoerli".

[guidiaz]

Created change request on https://docs.witnet.io.