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fob:laboratoare:08 [2022/09/27 14:18] 127.0.0.1 external edit |
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| - | ===== Laboratorul 08. ===== | + | ===== Liquidity Pools ===== |
| + | In this lab you will learn how to setup a Liquidity Pool. The original [[https://github.com/ElrondNetwork/sc-dex-rs/tree/main/dex/pair|Elrond's Pair SC]] will not be used, but we will use a [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/tree/master/labs/lab07| simplified version]]. | ||
| + | Please clone the git repo from [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/tree/master/labs/lab07|here]]. | ||
| + | |||
| + | Tasks for this practical session: | ||
| + | - Create tokens: First Token, Second Token, LiquidityPool Token (see previous labs) | ||
| + | - Build SC (see previous labs) | ||
| + | - Deploy SC (see previous labs) | ||
| + | - Set Roles of deployed SC: setTransferExecGasLimit, setLpTokenIdentifier, setSpecialRoleToken | ||
| + | - Add Liquidity | ||
| + | - Partially Remove Liquidity | ||
| + | - Perform Swaps: Trade token1 for token2 | ||
| + | |||
| + | Please check [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/master/labs/lab07/lab07/interaction/testnet.snippets.sh|interaction script]]. | ||
| + | You can use this file by sourcing it: | ||
| + | <code> | ||
| + | costin@Byblos:~/facultate/cursuri/fob/Foundation-Of-Blockchains/labs/lab07/lab07/interaction$ . testnet.snippets.sh | ||
| + | costin@Byblos:~/facultate/cursuri/fob/Foundation-Of-Blockchains/labs/lab07/lab07/interaction$ issueToken FobToken FOB | ||
| + | INFO:accounts:Account.sync_nonce() | ||
| + | INFO:accounts:Account.sync_nonce() done: 59 | ||
| + | INFO:transactions:Transaction.send: nonce=59 | ||
| + | INFO:transactions:Hash: 0a735360d68047ace30a26e64c7b0e67b654d227400b3929332efa05a52db344 | ||
| + | INFO:utils:View this transaction in the Elrond Testnet Explorer: https://testnet-explorer.elrond.com/transactions/0a735360d68047ace30a26e64c7b0e67b654d227400b3929332efa05a52db344 | ||
| + | { | ||
| + | "emittedTransaction": { | ||
| + | "nonce": 59, | ||
| + | "value": "50000000000000000", | ||
| + | "receiver": "erd1qqqqqqqqqqqqqqqpqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqzllls8a5w6u", | ||
| + | "sender": "erd1ld6er5zpdze3cynzkapur9qhzh826jje6n87g7tvdfrtszs8jn2qv44nqd", | ||
| + | "gasPrice": 1000000000, | ||
| + | "gasLimit": 60000000, | ||
| + | "data": "aXNzdWVANDY2RjYyNTQ2RjZCNjU2RUA0NjRGNDJARkZGRkZGRkZGRkZGRkZGRkZGRkZAMTI=", | ||
| + | "chainID": "T", | ||
| + | "version": 1, | ||
| + | "signature": "c30f1b3bf9edf0e4dea32ca89ba950165bb2d027797bfaf4d2629b6bec341464c7bd4cd93174fc440857b067871fffedb610272afb9013190dc1a5a03d65d709" | ||
| + | }, | ||
| + | "emittedTransactionData": "issue@466F62546F6B656E@464F42@FFFFFFFFFFFFFFFFFFFF@12", | ||
| + | "emittedTransactionHash": "0a735360d68047ace30a26e64c7b0e67b654d227400b3929332efa05a52db344", | ||
| + | "contractAddress": "erd1qqqqqqqqqqqqqqqpqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqzllls8a5w6u" | ||
| + | } | ||
| + | </code> | ||
| + | |||
| + | |||
| + | === Set Roles for deployed Pair SC === | ||
| + | |||
| + | Use [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/config.rs#L14|set_transfer_exec_gas_limit]] function to set the gas limit for transfer. This will set the //transfer_exec_gas_limit// variable from storage and will be further used by the contract. | ||
| + | |||
| + | Use [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/lib.rs#L520|setLpTokenIdentifier]] endpoint to set the LP Token for the Pair SC. This token will be used when users add and remove liquidity. For **X** Token1 and **X** Token2, the users will receive **Y** LP Token as proof that they provided liquidity. The user will use the LP Token to remove liquidity and get the tokens back. | ||
| + | |||
| + | Use [[https://docs.elrond.com/tokens/esdt-tokens/#setting-and-unsetting-special-roles|setSpecialRole]] to provide the Pair SC //setSpecialRoleToken// role so that it can create LP Tokens. | ||
| + | |||
| + | When deployed, the Pair SC is in **ActiveNoSwaps** state. Check [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/lib.rs#L73|this code]]. You will have to call [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/config.rs#L43|resume]] endpoint to change to state to **Active** so that swaps may be performed. | ||
| + | |||
| + | === Add and Remove Liquidity === | ||
| + | |||
| + | <note warning>To add liquidity to the Pair SC you have to send two tokens. Please use [[https://docs.elrond.com/sdk-and-tools/erdpy/smart-contract-interactions/#multi-esdt-transfer|Multi ESDT Transfer]] documentation.</note> | ||
| + | |||
| + | Now that the Pair SC is configured, you can call [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/lib.rs#L88|addLiquidity]] and [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/lib.rs#L190|removeLiquidity]]. | ||
| + | <note important>Check the transactions. What tokens were sent/received?</note> | ||
| + | |||
| + | The transactions should follow the order: | ||
| + | <code> | ||
| + | MultiESDTNFTTransfer@Contract_address_in_hex@02@Token1Identifier_in_hex@Token1Nonce_in_hex@Token1Value_in_hex@Token2Identifier_in_hex@Token2Nonce_in_hex@Token2Value_in_hex@myEndpoint_in_hex@parameters | ||
| + | </code> | ||
| + | |||
| + | === Swaps === | ||
| + | |||
| + | Now with the SC configured and having liquidity, you can perform swaps using [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/lib.rs#L351|swap_tokens_fixed_input]] and [[https://github.com/systems-cs-pub-ro/Foundation-Of-Blockchains/blob/5634f03ce56ba191a0e6685f6b5e675f02c9431f/labs/lab07/lab07/src/lib.rs#L438|swap_tokens_fixed_output]]. Remember the difference from last lab? | ||
| + | <note important>What happens with the ratio Token1/Token2?</note> | ||
| + | |||
| + | === Bonus === | ||
| + | |||
| + | This Pair SC has a vulnerability. Can you find it? | ||
