Firstly, i love sbt-ethereum. It is zippy and an absolute pleasure. Having completed the contract-interaction portion of the tutorial, I wanted to test out a live contract.

I would like to interact with the uniswap.io ETH-DAI-exchange contract directly from sbt-ethereum to obtain 2 DAI.

  1. I found the dai-token address by scrolling on etherscan
  2. Then used the Uniswap docs to get the uniswap-factory contract address
  3. Called ethTransactionView uniswap-factory getExchange dai-token
  4. This returned the uniswap-dai-exchange address (0x09cabec1ead1c0ba254b09efb3ee13841712be14)
  5. I verified that the Contract ABI on etherscan matched the github version
  6. Then I tried to obtain 2 DAI with a timer of 5 minutes. Varying combinations of input parameters (See A to E), including some with the [ETH to pay, optional] field, failed with the same error.
  7. I checked the dai contract, which seems to be 18 decimals, so I changed the DAI input to 2e18. I tried the optional payment in ether and in finney denominations. I also had a go with the ethToTokenSwapInput, specifying the amount of ETH rather than DAI, same outcome.

[error] com.mchange.sc.v2.jsonrpc.package$JsonrpcException: gas required exceeds allowance or always failing transaction [code=-32000]: No further information

I'm sure it's something simple I'm doing. The sending wallet is funded with >5 DAI worth of ETH.

Any ideas?

Note: I wasn't able to create the new sbt-ethereum tag as intended as reputation <150.

A: ethTransactionInvoke uniswap-dai-exchange ethToTokenSwapOutput 2 300

B: ethTransactionInvoke uniswap-dai-exchange ethToTokenSwapOutput 2 300 15 finney

C: ethTransactionInvoke uniswap-dai-exchange ethToTokenSwapOutput 2000000000000000000 300

D: ethTransactionInvoke uniswap-dai-exchange ethToTokenSwapOutput 2000000000000000000 300 15 finney

E: ethTransactionInvoke uniswap-dai-exchange ethToTokenSwapOutput 2000000000000000000 300 0.015 ether

  • The deadline parameter has to be a unix timestamp.
    – Ismael
    May 5, 2019 at 20:52

1 Answer 1


First, thanks a ton for trying out sbt-ethereum (and for liking it!).

I was able I think to make the transaction you want to do work. There are two issues:

  1. As @Ismael says, the deadline should be a unix timestamp. (Given the prevalence of these, I should probably add a utility for easily computing them in sbt-ethereum.)

  2. The function you are calling is marked @payable, and does indeed require that you pay the amount of ether you are willing to make available for the swap. It occurs to me that the sbt-ethereum tutorial fails to much emphasize this, but when calling payable functions, after you supply the function arguments you can supply the amount you wish to pay as a number and unit. (Update: I see that you already did notice and try this! So it was mostly just the deadline.)

Another issue is that DAI decimals are 18, so we want 2 plus a lotta zeroes if we just want 2 DAI tokens. (The uint parser in sbt-ethereum doesn't support scientific notation, another thing to remedy!)

So, when all is said and done we have...

> ethTransactionInvoke unverified-uniswap-dai-exchange ethToTokenSwapOutput 2000000000000000000 1557109479 0.015 ether
[info] Unlocking address '0x465e79b940bc2157e4259ff6b2d92f454497f1e4' (on chain with ID 1, aliases ['default-sender','testing0'])
Enter passphrase or hex private key for address '0x465e79b940bc2157e4259ff6b2d92f454497f1e4': *******************
[info] V3 wallet(s) found for '0x465e79b940bc2157e4259ff6b2d92f454497f1e4' (aliases ['default-sender','testing0'])

==> T R A N S A C T I O N   S U B M I S S I O N   R E Q U E S T
==> The transaction would be a message with...
==>   To:    0x09cabec1ead1c0ba254b09efb3ee13841712be14 (with aliases ['unverified-uniswap-dai-exchange'] on chain with ID 1)
==>   From:  0x465e79b940bc2157e4259ff6b2d92f454497f1e4 (with aliases ['default-sender','testing0'] on chain with ID 1)
==>   Data:  0x6b1d4db70000000000000000000000000000000000000000000000001bc16d674ec80000000000000000000000000000000000000000000000000000000000005ccf9ae7
==>   Value: 0.015 Ether
==> The transaction is signed with Chain ID 1 (which correctly matches the current session's 'ethNodeChainId').
==> According to the ABI currently associated with the 'to' address, this message would amount to the following method call...
==>   Function called: ethToTokenSwapOutput(uint256,uint256)
==>     Arg 1 [name=tokens_bought, type=uint256]: 2000000000000000000
==>     Arg 2 [name=deadline, type=uint256]: 1557109479
==> The nonce of the transaction would be 407.
==> $$$ The transaction you have requested could use up to 66235 units of gas.
==> $$$ You would pay 3 gwei for each unit of gas, for a maximum cost of 0.000198705 ether.
==> $$$ This is worth 0.031652712975 USD (according to Coinbase at 7:20 PM).
==> $$$ You would also send 0.015 ether (2.389425 USD), for a maximum total cost of 0.015198705 ether (2.421077712975 USD).

Would you like to submit this transaction? [y/n] y
A transaction with hash '0x0509bafc336c760f21e6c7a1c491d7ba86a6c17c18ec46eec8d87d4995afd8e6' will be submitted. Please wait.
[info] Called function 'ethToTokenSwapOutput', with args '2000000000000000000, 1557109479', sending 15000000000000000 wei to address '0x09cabec1ead1c0ba254b09efb3ee13841712be14' in transaction '0x0509bafc336c760f21e6c7a1c491d7ba86a6c17c18ec46eec8d87d4995afd8e6'.
[info] Waiting for the transaction to be mined (will wait up to 5 minutes).
[info] Transaction Receipt:
[info]        Transaction Hash:    0x0509bafc336c760f21e6c7a1c491d7ba86a6c17c18ec46eec8d87d4995afd8e6
[info]        Transaction Index:   122
[info]        Transaction Status:  SUCCEEDED
[info]        Block Hash:          0x3257d8fd31b49c2c7d55d72c0fddd01f02b92a3326529ed903fdd0e6cb520f9d
[info]        Block Number:        7704627
[info]        From:                0x465e79b940bc2157e4259ff6b2d92f454497f1e4
[info]        To:                  0x09cabec1ead1c0ba254b09efb3ee13841712be14
[info]        Cumulative Gas Used: 6482478
[info]        Gas Used:            54719
[info]        Contract Address:    None
[info]        Logs:                0 => EthLogEntry [source=0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359] (
[info]                                    topics=[
[info]                                      0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef,
[info]                                      0x00000000000000000000000009cabec1ead1c0ba254b09efb3ee13841712be14,
[info]                                      0x000000000000000000000000465e79b940bc2157e4259ff6b2d92f454497f1e4
[info]                                    ],
[info]                                    data=0000000000000000000000000000000000000000000000001bc16d674ec80000
[info]                                  ),
[info]                             1 => EthLogEntry [source=0x09cabec1ead1c0ba254b09efb3ee13841712be14] (
[info]                                    topics=[
[info]                                      0xcd60aa75dea3072fbc07ae6d7d856b5dc5f4eee88854f5b4abf7b680ef8bc50f,
[info]                                      0x000000000000000000000000465e79b940bc2157e4259ff6b2d92f454497f1e4,
[info]                                      0x000000000000000000000000000000000000000000000000002c13f43dbb6c42,
[info]                                      0x0000000000000000000000000000000000000000000000001bc16d674ec80000
[info]                                    ],
[info]                                    data=
[info]                                  )
[info]        Events:              0 => Transfer [source=0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359] (
[info]                                    _from (of type address): 0x09cabec1ead1c0ba254b09efb3ee13841712be14,
[info]                                    _to (of type address): 0x465e79b940bc2157e4259ff6b2d92f454497f1e4,
[info]                                    _value (of type uint256): 2000000000000000000
[info]                                  ),
[info]                             1 => TokenPurchase [source=0x09cabec1ead1c0ba254b09efb3ee13841712be14] (
[info]                                    buyer (of type address): 0x465e79b940bc2157e4259ff6b2d92f454497f1e4,
[info]                                    eth_sold (of type uint256): 12406838703909954,
[info]                                    tokens_bought (of type uint256): 2000000000000000000
[info]                                  )
[success] Total time: 37 s, completed May 5, 2019 7:20:27 PM

sbt:ethdocstore> ethTransactionView 0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359 balanceOf testing0
[info] The function 'balanceOf' yields 1 result.
[info]  + Result 1 of type 'uint256', named 'balance', is 2000000000000000002
[success] Total time: 1 s, completed May 5, 2019 7:26:36 PM

The extra 2 atoms at the end of the account balance are due to my originally trying without all those extra zeroes.

You can see if you review the successful transaction, for my 2 DAI I sent out 0.015 ether, but (in an "internal transaction") got 0.002593161296090046 ether back as change.

Thanks again for giving sbt-ethereum a shot. I hope this helps!

p.s. If you want to compute the UNIX timestamp for a 300 second (5 minute) deadline in sbt-ethereum as it is, you can do..

> consoleQuick
[info] Starting scala interpreter...
Welcome to Scala 2.12.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_172).
Type in expressions for evaluation. Or try :help.

scala> (System.currentTimeMillis / 1000) + 300
res0: Long = 1557110378


Obviously it'd be better not to have to drop into a Scala REPL to do this, though.

  • Thanks Ismael you were spot on. My deadline was indeed set to a few mins after New Year's 1970. May 6, 2019 at 8:25
  • I really do like the tool, and think others will too! It's responsive and customisable a way that no chrome extension has ever been. May 6, 2019 at 8:29

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