This guide should serve to allow users to create their own exit pool transactions for weighted pools manually in the event of the ui being inaccessible.
Note: If your BPT is deposited into a gauge earning rewards (or deposited into Aura), you will need to withdraw from there first.
Let's first familiarize ourself with what an exit pool looks like.
https://etherscan.io/tx/0xec1e3fdc774542cd93a8f8bc8a0d2216b52d0ece1097faa952d58ce0bb7d9698
Go to the Balancer vault address on etherscan and scroll down until you see "contract abi". Copy this and go to https://abi.hashex.org/ select autoparse, and paste the abi into the text box and click parse. Then under "function" select "exitPool" https://etherscan.io/address/0xba12222222228d8ba445958a75a0704d566bf2c8#code
It should look like this
The exitpool transaction is made up of four parts, poolId, sender, recipient, request
poolId: You can find this by going to the LP token contract address, going to "contract" tab on etherscan then "read contract" and item 12 should be getPoolId, which should look like this 0xcfca23ca9ca720b6e98e3eb9b6aa0ffc4a5c08b9000200000000000000000274
Sender: this is your address
Recipient: this is also your address
And finally, the most complex one,
Request is a struct made up of address[],uint256[],bytes,bool corresponding with:
[contract addresses, amounts, userData, toInternalBalance]
it is fine if you don't know what this means, I will show you how to encode it.
Let's break down each part of the request. Get a text file and fill out these parameters as we go and we will put it together at the end.
this is an array of contract addresses for the assets in the pool.
If you already know the asset contract addresses, you can skip this part. Go to the balancer vault on etherscan, and go to contract>read contract then find 10. getPoolTokens. Input the poolid and hit query and it should return the array of tokens like this
It should look like this
["0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "0xC0c293ce456fF0ED870ADd98a0828Dd4d2903DBF"]
the addresss above must be sorted lowest to highest, in terms of leading hexadecimal digits. with 1 < 5< a < f. In this case 0xC02 is less than 0xC0c. If you get BAL#102 this is whats causing it.
is where we will be encoding our amounts out. You must be aware of the decimals on the token (can be found on the token page on etherscan) and adjust accordingly per asset. You can find out how much underlying assets your pool tokens are worth on the balancer ui, and wallet viewers like debank, zapper, etc. Note that you have have to apply slippage at this stage so if you have a slippage of 1% (remember if it goes outside this range before being executed the transaction will fail, wasting precious gas), subtract 1% from both assets.
I'll work off the same example from above, which used the amounts
["11769299331677283777","10012399421913945132007"]
Which normalized from 18 decimals is 11.7692993317 and 10012.3994219. Note that the order of this array corresponds with the order of assets in the above address[] array.
This data basically describes
- what exit type it is (proportional in this case) and
- how much BPT to burn
It looks like this
0x0000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000022ee66da08cf2d48ef
Lets split them up by part
0000000000000000000000000000000000000000000000000000000000000001
This is the exit type. Simply leave this as is for proportional exits.
000000000000000000000000000000000000000000000022ee66da08cf2d48ef
Is our bpt amount in hex. A hex to decimal conversion shows this value to be 644367956066146535663 or 644.367956066 adjusted for 18 decimals (which all bpt are).
To encode this value, go to https://abi.hashex.org/ and select Add Argument and select UINT256 then type in your BPT amount
You can get your BPT amount by going to the pool token contract, clicking contract> read contract and going to balanceOf() and inputting your address. Whatever it returns is how much BPT you hold in 18 decimals. Input that into the site above and copy the resulting "encoded data" at the bottom. It should look like this
000000000000000000000000000000000000000000000022ee66da08cf2d48ef
Now we put these two parts together with a 0x at the beginning so
0x + 0000000000000000000000000000000000000000000000000000000000000001 + 000000000000000000000000000000000000000000000022ee66da08cf2d48ef =
0x0000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000022ee66da08cf2d48ef
Which is our userData
The final parameter relates to whether the resulting output is to internal balances. You can just set it to false if you don't intend to use internal balances (which you probably don't).
So now we put these four pieces together in an array like this
[address[],uint256[],bytes,bool]
So the Request looks like this
[["0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "0xC0c293ce456fF0ED870ADd98a0828Dd4d2903DBF"],["11769299331677283777","10012399421913945132007"],"0x0000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000022ee66da08cf2d48ef",false]
Now go back to the hashex site with the exitPool function selected and lets fill in the data. We already explained poolId, sender and recipient. Now copy the entire Request struct starting with the opening [ and ending with the closing ] into the request struct box. It should look like this
Now that the transaction is created, we now have to send it. In order to send custom transactions through metamask, we first must go to settings>advanced>"show hex data" and enable it. Next go to send, and with the "to" address being the balancer vault 0xBA12222222228d8Ba445958a75a0704d566BF2C8
In the "hex data" section on metamask, input the "encoded data" at the bottom of the above image. Note that if there are any errors in the tx construction, it will say the transaction is likely to fail. If its only estimating 21000 gas, that means the transaction will fail.
Assuming everything is right, sending this transaction will withdraw from the weighted pool.