CODEWITHSUNDEEP
nearprotocol
sirwillem
sirwillem

Reputation: 722

How do you estimate the gas usage of a NEAR smart contract method call?

Is there a tool that can estimate how much gas a contract call will make before submitting to the NEAR network?

Upvotes: 3

Views: 677

Answers (2)

Vlad Grichina
Vlad Grichina

Reputation: 1069

The easiest way to do it is to submit sample transaction with more than needed gas attached and then check in explorer how much gas was used, e.g. see https://explorer.testnet.near.org/transactions/23dgV15pydiVhirWJ4He7TMoyRJM2DUXtcWb7VXFSy2G

300 Tgas was attached and 47 Tgas used for that given transaction.

Upvotes: 1

sirwillem
sirwillem

Reputation: 722

Currently the best estimation is to use runtime-standalone, which can process transactions without having to worry about consensus/networking. This means you can create accounts, deploy contracts, and invoke them and the outcome returned includes how much gas was burnt and used. The difference being burnt gas is used to execute the function call and used gas is how much was used by contract promise calls.

However, it's currently a MVP prototype and has only been used to test our core contract, here is it being used to test the lockup contract.

If your contract method doesn't invoke any batch promises and only normal promises,the mock runtime in near-sdk-as provides a way to create accounts and "deploy" contracts. It does this by internally using the binary of near-vm-runner-standalone, which is a rust crate. The binary provides a CLI to invoke a single transaction, which takes as input the current state of the contract being called, the contract's binary, the config file that defines the current context (who is calling the contract, how much gas is prepaid, etc), and a config for the cost of different fees. It then returns the updated state, the outcome of the transaction (e.g. how much gas was used and any receipts of transactions queued by promise calls).

The near-vm-runner-standalone is also published to npm with the package name: near-vm, which is what the mock runtime uses.

This is still an active area of development and we hope to turn runtime standalone into a useful easy to use tool for testing and gas estimation.

Upvotes: 2

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