mirror of
https://github.com/jwinterm/grin-wallet.git
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06ab92a619
* wallet: update lmdb from store crate, migrate single backend from trait to struct, update tests cargo deps and design doc * backend: do not panic on iter and directory creation * return iterator errors * build: update to last node revision * fix: height selection for scan, remove unused mutability for wallet * wallet: remove unused mutability conversion * tx: store slate state at database * build: cargo fmt * fix: do not return error when slate not found on tx slate state update * lmdb: do not collect all tx log records at iterator, show read errors at log * fix: save slate state, return error if slate not found * tx: specify amount of bad txs on slate state update error --------- Co-authored-by: Joerg <wiesche89@googlemail.com>
82 lines
5.3 KiB
Markdown
82 lines
5.3 KiB
Markdown
# Grin Wallet + Library Design
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## High Level Wallet Design Overview
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The current Grin `wallet` crate provides several layers of libraries, services, and traits that can be mixed, matched and reimplemented to support
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various needs within the default Grin wallet as well as provide a set of useful library functions for 3rd-party implementors. At a very high level,
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the code is organized into the following components (from highest-level to lowest):
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* **Command Line Client** - The command line client invoked by `grin-wallet [command]`, simply instantiates the other components below
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and parses command line arguments as needed.
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* **Web Wallet Client** - [Work In Progress] A web wallet client accessible from the local machine only. Current code can be viewed here:
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https://github.com/mimblewimble/grin-web-wallet
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* **Static File Server** - [TBD] A means of serving up the web wallet client above to the user (still under consideration)
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* **libWallet** - A high level wallet library that provides functions for the default grin wallet. The functions in here can be somewhat
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specific to how the grin wallet does things, but could still be reused by 3rd party implementors following the same basic principles as grin
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does. Major functionality is split into:
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* **Owner API** - An API that provides information that should only be viewable by the wallet owner
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* **Foreign API** - An API to communicate with other wallets and external grin nodes
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* **Service Controller** - A Controller that instantiates the above APIs (either locally or via web services)
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* **Internal Functions** Helper functions to perform needed wallet tasks, such as selecting coins, updating wallet outputs with
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results from a Grin node, etc.
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* **libTx** - Library that provides lower-level transaction building, rangeproof and signing functions, highly-reusable by wallet implementors.
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* **Wallet Traits** - A set of generic traits defined within libWallet and the `keychain` crate . A wallet implementation such as Grin's current
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default only needs to implement these traits in order to provide a wallet:
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* **NodeClient** - Defines communication between the wallet, a running grin node and/or other wallets
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* **WalletBackend** - Defines the storage implementation of the wallet
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* **KeyChain** - Defines key derivation operations
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## Module-Specific Notes
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A full API-Description for each of these parts is still TBD (and should be generated by rustdoc rather than repeated here). However a few design
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notes on each module are worth mentioning here.
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### Web Wallet Client / Static File Server
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This component is not a 3rd-party hosted 'Web Wallet' , but a client meant to be run on the local machine only by the wallet owner. It should provide
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a usable browser interface into the wallet, that should be functionally equivalent to using the command line but (hopefully) far easier to use.
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It is currently not being included by a default grin build, although the required listener is currently being run by default. To build and test this
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component, see instructions on the [project page](https://github.com/mimblewimble/grin-web-wallet). The 'Static File Server' is still under
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discussion, and concerns how to provide the web-wallet to the user in a default Grin build.
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### Owner API / Foreign API
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The high-level wallet API has been split into two, to allow for different requirements on each. For instance, the Foreign API would listen on
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an external-facing port, and therefore potentially has different security requirements from the Owner API, which can simply be bound to localhost
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only.
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### libTX
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Transactions are built using the concept of a 'Slate', which is a data structure that gets passed around to all participants in a transaction,
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with each appending their Inputs, Outputs or Signatures to it to build a completed wallet transaction. Although the current mode of operation in
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the default client only supports single-user - single recipient, an arbitrary number of participants to a transaction is supported within libTX.
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### Wallet Traits
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In the current code, a Wallet implementation is just a combination of these two traits. The vast majority of functions within libwallet
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and libTX have a signature similar to the following:
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```rust
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pub fn retrieve_outputs<T: ?Sized, C, K>(
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!·wallet: &mut WalletBackend<C, K>,
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!·show_spent: bool,
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!·tx_id: Option<u32>,
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) -> Result<Vec<OutputData>, Error>
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where
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!·C: NodeClient,
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!·K: Keychain,
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{
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```
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Provided `WalletBackend` parameterized with implementations of `NodeClient` and `Keychain`.
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There is currently only a single implementation of the Keychain trait within the Grin code, in the `keychain` crate exported as `ExtKeyChain`.
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The `Keychain` trait makes several assumptions about the underlying implementation, particularly that it will adhere to a
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[BIP-38 style](https://github.com/bitcoin/bips/blob/master/bip-0038.mediawiki) 'master key -> child key' model.
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There are two implementations of `NodeClient` within the code, the main version being the `HTTPNodeClient` found within `wallet/src/client.rs` and
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the seconds a test client that communicates with an in-process instance of a chain. The NodeClient isolates all network calls, so upgrading wallet
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communication from the current simple http interaction to a more secure protocol (or allowing for many options) should be a simple
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matter of dropping in different `NodeClient` implementations. |