Merge pull request #500 from onflow/improve-coa-creation-transaction

Improve COA creation transaction to gracefully handle existing COA in storage

services/requester/cadence/create_coa.cdc

@@ -3,24 +3,29 @@ import FungibleToken
 import FlowToken
 
 transaction(amount: UFix64) {
-    let sentVault: @FlowToken.Vault
     let auth: auth(Storage) &Account
 
     prepare(signer: auth(Storage) &Account) {
-        let vaultRef = signer.storage.borrow<auth(FungibleToken.Withdraw) &FlowToken.Vault>(
-            from: /storage/flowTokenVault
-        ) ?? panic("Could not borrow reference to the owner's Vault!")
-
-        self.sentVault <- vaultRef.withdraw(amount: amount) as! @FlowToken.Vault
         self.auth = signer
     }
 
     execute {
+        // If the COA is already created & saved, there's nothing to do, just return.
+        if let coa = self.auth.storage.borrow<&EVM.CadenceOwnedAccount>(from: /storage/evm) {
+            return
+        }
+
+        let vaultRef = self.auth.storage.borrow<auth(FungibleToken.Withdraw) &FlowToken.Vault>(
+            from: /storage/flowTokenVault
+        ) ?? panic("Could not borrow reference to the owner's Vault!")
+        let vault <- vaultRef.withdraw(amount: amount) as! @FlowToken.Vault
+
         let account <- EVM.createCadenceOwnedAccount()
-        log(account.address())
-        account.deposit(from: <-self.sentVault)
+        account.deposit(from: <-vault)
 
-        log(account.balance())
-        self.auth.storage.save<@EVM.CadenceOwnedAccount>(<-account, to: StoragePath(identifier: "evm")!)
+        self.auth.storage.save<@EVM.CadenceOwnedAccount>(
+            <-account,
+            to: /storage/evm
+        )
     }
 }

services/requester/requester.go

@@ -181,17 +181,18 @@ func NewEVM(
 
 	// create COA on the account
 	if config.CreateCOAResource {
-		// we ignore errors for now since creation of already existing COA resource will fail, which is fine for now
 		tx, err := evm.buildTransaction(
 			context.Background(),
 			evm.replaceAddresses(createCOAScript),
 			cadence.UFix64(coaFundingBalance),
 		)
 		if err != nil {
 			logger.Warn().Err(err).Msg("COA resource auto-creation failure")
+			return nil, fmt.Errorf("COA resource auto-creation failure: %w", err)
 		}
 		if err := evm.client.SendTransaction(context.Background(), *tx); err != nil {
 			logger.Warn().Err(err).Msg("failed to send COA resource auto-creation transaction")
+			return nil, fmt.Errorf("failed to send COA resource auto-creation transaction: %w", err)
 		}
 	}