Investigation into tx fees in ink! smart contracts

Repo demonstrating fees being taken for adding storage to a contract and subsequently being refunded when the contract is terminated.

Prerequisites

Substrate node running on local machine

docker run -p 9944:9944 -p 9933:9933 -p 9615:9615 -d prosopo/substrate:dev-aura-aadbbed50ede27817158c7517f13f6f61c9cf000

Build the contract

cd contract &&
RUST_LOG=debug cargo contract build --manifest-path ./Cargo.toml --verbose --keep-debug-symbols --generate all

Set up env vars

Copy the env.development file and set the path to your contract resources

cp env.development .env.development

DAPP_WASM_PATH=<YOUR_PATH>batching/contract/target/ink/dapp.wasm
DAPP_ABI_PATH=<YOUR_PATH>batching/contract/target/ink/dapp.json

Install the dependencies and build

npm i && \
npm run build

Deploy the contract

npm run deploy

Run the transactions

npm run tx

Sending address: 5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty Payment Info: 1.9845 Unit faucet response.storageDeposit { Charge: '480.0000 Unit' } Block number 13886 Balance before: 995284288 UNIT, Balance after: 995283806 UNIT

Tx Cost: 481 UNIT for extrinsic without sub call

Sending address: 5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty Payment Info: 1.9845 Unit faucetWithStore response.storageDeposit { Charge: '480.0000 Unit' } Block number 13887 Balance before: 995283806 UNIT, Balance after: 995283324 UNIT

Tx Cost: 481 UNIT for extrinsic with sub call

Sending address: 5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty Payment Info: 1.9845 Unit terminate response.storageDeposit { Refund: '2.4090 kUnit' } Block number 13888 Balance before: 995283324 UNIT, Balance after: 995285832 UNIT

Tx Cost: -2507 UNIT for terminate extrinsic

prosopo/batching