This PR implements a new version of the abigen utility (v2) which exists
along with the pre-existing v1 version.
Abigen is a utility command provided by go-ethereum that, given a
solidity contract ABI definition, will generate Go code to transact/call
the contract methods, converting the method parameters/results and
structures defined in the contract into corresponding Go types. This is
useful for preventing the need to write custom boilerplate code for
contract interactions.
Methods in the generated bindings perform encoding between Go types and
Solidity ABI-encoded packed bytecode, as well as some action (e.g.
`eth_call` or creating and submitting a transaction). This limits the
flexibility of how the generated bindings can be used, and prevents
easily adding new functionality, as it will make the generated bindings
larger for each feature added.
Abigen v2 was conceived of by the observation that the only
functionality that generated Go bindings ought to perform is conversion
between Go types and ABI-encoded packed data. Go-ethereum already
provides various APIs which in conjunction with conversion methods
generated in v2 bindings can cover all functionality currently provided
by v1, and facilitate all other previously-desired use-cases.
## Generating Bindings
To generate contract bindings using abigen v2, invoke the `abigen`
command with the `--v2` flag. The functionality of all other flags is
preserved between the v2 and v1 versions.
## What is Generated in the Bindings
The execution of `abigen --v2` generates Go code containing methods
which convert between Go types and corresponding ABI-encoded data
expected by the contract. For each input-accepting contract method and
the constructor, a "packing" method is generated in the binding which
converts from Go types to the corresponding packed solidity expected by
the contract. If a method returns output, an "unpacking" method is
generated to convert this output from ABI-encoded data to the
corresponding Go types.
For contracts which emit events, an unpacking method is defined for each
event to unpack the corresponding raw log to the Go type that it
represents.
Likewise, where custom errors are defined by contracts, an unpack method
is generated to unpack raw error data into a Go type.
## Using the Generated Bindings
For a smooth user-experience, abigen v2 comes with a number of utility
functions to be used in conjunction with the generated bindings for
performing common contract interaction use-cases. These include:
* filtering for historical logs of a given topic
* watching the chain for emission of logs with a given topic
* contract deployment methods
* Call/Transact methods
https://geth.ethereum.org will be updated to include a new tutorial page
for abigen v2 with full code examples. The page currently exists in a
PR: https://github.com/ethereum/go-ethereum/pull/31390 .
There are also extensive examples of interactions with contract bindings
in [test
cases](cc855c7ede/accounts/abi/bind/v2/lib_test.go)
provided with this PR.
---------
Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
This is a rewrite of the 'simulated backend', an implementation of the ethclient interfaces
which is backed by a simulated blockchain. It was getting annoying to maintain the old
version of the simulated backend feature because there was a lot of code duplication with
the main client.
The new version is built using parts that we already have: an in-memory geth node instance
running in developer mode provides the chain, while the Go API is provided by ethclient.
A backwards-compatibility wrapper is provided, but the simulated backend has also moved to
a more sensible import path: github.com/ethereum/go-ethereum/ethclient/simulated
---------
Co-authored-by: Felix Lange <fjl@twurst.com>
Co-authored-by: Gary Rong <garyrong0905@gmail.com>
* api/bind: Add CallOpts.BlockHash to allow calling contracts at a specific block hash.
* ethclient: Add BalanceAtHash, NonceAtHash and StorageAtHash functions
* accounts/abi/bind: fix bounded contracts and sim backend for 1559
* accounts/abi/bind, ethclient: don't rely on chain config for gas prices
* all: enable London for all internal tests
* les: get receipt type info in les tests
* les: fix weird test
Co-authored-by: Martin Holst Swende <martin@swende.se>
There is no need to depend on the old context package now that the
minimum Go version is 1.7. The move to "context" eliminates our weird
vendoring setup. Some vendored code still uses golang.org/x/net/context
and it is now vendored in the normal way.
This change triggered new vet checks around context.WithTimeout which
didn't fire with golang.org/x/net/context.
The need for these functions comes up in code that actually deploys and
uses contracts. As of this commit, they can be used with both
SimulatedBackend and ethclient.
SimulatedBackend gains some additional methods in the process and is now
safe for concurrent use.
In this commit, contract bindings and their backend start using the
Ethereum Go API interfaces offered by ethclient. This makes ethclient a
suitable replacement for the old remote backend and gets us one step
closer to the final stable Go API that is planned for go-ethereum 1.5.
The changes in detail:
* Pending state is optional for read only contract bindings.
BoundContract attempts to discover the Pending* methods via an
interface assertion. There are a couple of advantages to this:
ContractCaller is just two methods and can be implemented on top of
pretty much anything that provides Ethereum data. Since the backend
interfaces are now disjoint, ContractBackend can simply be declared as
a union of the reader and writer side.
* Caching of HasCode is removed. The caching could go wrong in case of
chain reorganisations and removing it simplifies the code a lot.
We'll figure out a performant way of providing ErrNoCode before the
1.5 release.
* BoundContract now ensures that the backend receives a non-nil context
with every call.
