Onchain.Aave.DebtToken (onchain_aave v0.2.0)

Aave V3 debt token credit delegation reads and writes.

Credit delegation lives on the variable/stable debt token contracts, not the Pool. Use debt_token_address/3 to resolve the debt token for an asset and rate mode via Pool.getReserveData/1, then approve_delegation/4 to grant or revoke (amount 0) borrowing power and borrow_allowance/3 to read the current allowance.

Error Format

Errors pass through from underlying modules:

Source	Error Shape
`Onchain.Address.validate/1`	`{:error, {:invalid_address, input}}`
`Onchain.Aave.Contracts.address/2`	`{:error, {:unsupported_network, network}}`
`Onchain.ABI.encode_call/2`	`{:error, {:encode_error, reason}}`
`Onchain.RPC.eth_call/3`	`{:error, {:rpc_error, map}}`
`Onchain.ABI.decode_response/2`	`{:error, {:decode_error, reason}}`
`Onchain.Signer.send_transaction/3`	`{:error, {:missing_option, ...}}`, `{:error, {:sign_error, ...}}`, etc.
Interest rate mode validation	`{:error, {:invalid_interest_rate_mode, value}}`

Functions

Function	Purpose
`debt_token_address/3`	Resolve variable/stable debt token address for an asset
`approve_delegation/4`	Grant or revoke delegated borrow allowance (returns tx hash)
`borrow_allowance/3`	Read delegated borrow allowance between two addresses

API Functions

Function	Arity	Description	Param Kinds
`borrow_allowance`	4	Read the delegated borrow allowance between two addresses.	`debt_token: value`, `from_user: value`, `to_user: value`, `opts: value`
`approve_delegation`	4	Approve or revoke credit delegation on a debt token.	`debt_token: value`, `delegatee: value`, `amount: value`, `opts: value`
`debt_token_address`	3	Resolve the variable or stable debt token address for an asset.	`asset: value`, `rate_mode: value`, `opts: value`

Summary

Functions

approve_delegation(debt_token, delegatee, amount, opts)

Approve or revoke credit delegation on a debt token.

borrow_allowance(debt_token, from_user, to_user, opts \\ [])

Read the delegated borrow allowance between two addresses.

debt_token_address(asset, rate_mode, opts \\ [])

Resolve the variable or stable debt token address for an asset.

Functions

approve_delegation(debt_token, delegatee, amount, opts)

@spec approve_delegation(
  String.t() | binary(),
  String.t() | binary(),
  non_neg_integer(),
  keyword()
) ::
  {:ok, String.t()} | {:error, term()}

Approve or revoke credit delegation on a debt token.

Parameters

debt_token - Variable or stable debt token contract address (value)
delegatee - Address receiving delegated borrowing power (value)
amount - Delegated borrow amount (raw integer); use 0 to revoke (value)
opts - Required: :private_key, :nonce, :chain_id, :rpc_url. Optional: :gas_limit (recommend ~120k) (value)

Returns

Transaction hash hex string ({:ok, String.t()} | {:error, term()})

# descripex:contract
%{
  params: %{
    opts: %{
      description: "Required: :private_key, :nonce, :chain_id, :rpc_url. Optional: :gas_limit (recommend ~120k)",
      kind: :value
    },
    amount: %{
      description: "Delegated borrow amount (raw integer); use 0 to revoke",
      kind: :value
    },
    debt_token: %{
      description: "Variable or stable debt token contract address",
      kind: :value
    },
    delegatee: %{
      description: "Address receiving delegated borrowing power",
      kind: :value
    }
  },
  returns: %{
    type: "{:ok, String.t()} | {:error, term()}",
    description: "Transaction hash hex string"
  }
}

borrow_allowance(debt_token, from_user, to_user, opts \\ [])

@spec borrow_allowance(
  String.t() | binary(),
  String.t() | binary(),
  String.t() | binary(),
  keyword()
) ::
  {:ok, non_neg_integer()} | {:error, term()}

Read the delegated borrow allowance between two addresses.

Parameters

debt_token - Variable or stable debt token contract address (value)
from_user - Delegator address (value)
to_user - Delegatee address (value)
opts - Options: :rpc_url, :timeout, :block (default: [], value)

Returns

Delegated borrow allowance in underlying asset units ({:ok, non_neg_integer()} | {:error, term()})

# descripex:contract
%{
  params: %{
    opts: %{
      default: [],
      description: "Options: :rpc_url, :timeout, :block",
      kind: :value
    },
    debt_token: %{
      description: "Variable or stable debt token contract address",
      kind: :value
    },
    from_user: %{description: "Delegator address", kind: :value},
    to_user: %{description: "Delegatee address", kind: :value}
  },
  returns: %{
    type: "{:ok, non_neg_integer()} | {:error, term()}",
    description: "Delegated borrow allowance in underlying asset units"
  }
}

debt_token_address(asset, rate_mode, opts \\ [])

@spec debt_token_address(String.t() | binary(), :variable | :stable, keyword()) ::
  {:ok, String.t()} | {:error, term()}

Resolve the variable or stable debt token address for an asset.

Parameters

asset - Underlying reserve asset address (value)
rate_mode - Interest rate mode: :variable or :stable (value)
opts - Options: :network (default :ethereum), :rpc_url, :timeout, :block (default: [], value)

Returns

Checksummed debt token contract address ({:ok, String.t()} | {:error, term()})

# descripex:contract
%{
  params: %{
    opts: %{
      default: [],
      description: "Options: :network (default :ethereum), :rpc_url, :timeout, :block",
      kind: :value
    },
    asset: %{description: "Underlying reserve asset address", kind: :value},
    rate_mode: %{
      description: "Interest rate mode: :variable or :stable",
      kind: :value
    }
  },
  returns: %{
    type: "{:ok, String.t()} | {:error, term()}",
    description: "Checksummed debt token contract address"
  }
}