lighthouse/common/eth2_wallet_manager/src/locked_wallet.rs
Michael Sproul 3486d6a809 Use OS file locks in validator client (#1958)
## Issue Addressed

Closes #1823

## Proposed Changes

* Use OS-level file locking for validator keystores, eliminating problems with lockfiles lingering after ungraceful shutdowns (`SIGKILL`, power outage). I'm using the `fs2` crate because it's cross-platform (unlike `file-lock`), and it seems to have the most downloads on crates.io.
* Deprecate + disable `--delete-lockfiles` CLI param, it's no longer necessary
* Delete the `validator_dir::Manager`, as it was mostly dead code and was only used in the `validator list` command, which has been rewritten to read the validator definitions YAML instead.

## Additional Info

Tested on:

- [x] Linux
- [x] macOS
- [x] Docker Linux
- [x] Docker macOS
- [ ] Windows
2020-11-26 11:25:46 +00:00

95 lines
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Rust
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use crate::{
filesystem::{read, update},
Error,
};
use eth2_wallet::{Uuid, ValidatorKeystores, Wallet};
use lockfile::Lockfile;
use std::path::{Path, PathBuf};
pub const LOCK_FILE: &str = ".lock";
/// Represents a `Wallet` in a `wallet_dir`.
///
/// For example:
///
/// ```ignore
/// <wallet_dir>
/// └── .lock
/// └── <wallet-json>
/// ```
///
/// Provides the following functionality:
///
/// - Control over the `.lock` file to prevent concurrent access.
/// - A `next_validator` function which wraps `Wallet::next_validator`, ensuring that the wallet is
/// persisted to disk (as JSON) between each consecutive call.
pub struct LockedWallet {
wallet_dir: PathBuf,
wallet: Wallet,
_lockfile: Lockfile,
}
impl LockedWallet {
/// Opens a wallet with the `uuid` from a `base_dir`.
///
/// ```ignore
/// <base-dir>
/// ├── <uuid (directory)>
///    └── <uuid (json file)>
/// ```
///
/// ## Errors
///
/// - If the wallet does not exist.
/// - There is file-system or parsing error.
/// - The lock-file already exists.
pub(crate) fn open<P: AsRef<Path>>(base_dir: P, uuid: &Uuid) -> Result<Self, Error> {
let wallet_dir = base_dir.as_ref().join(format!("{}", uuid));
if !wallet_dir.exists() {
return Err(Error::MissingWalletDir(wallet_dir));
}
let _lockfile = Lockfile::new(wallet_dir.join(LOCK_FILE))?;
Ok(Self {
wallet: read(&wallet_dir, uuid)?,
wallet_dir,
_lockfile,
})
}
/// Returns a reference to the underlying wallet.
///
/// Note: this does not read from the file-system on each call. It assumes that the wallet does
/// not change due to the use of a lock-file.
pub fn wallet(&self) -> &Wallet {
&self.wallet
}
/// Calls `Wallet::next_validator` on the underlying `wallet`.
///
/// Ensures that the wallet JSON file is updated after each call.
///
/// ## Errors
///
/// - If there is an error generating the validator keys.
/// - If there is a file-system error.
pub fn next_validator(
&mut self,
wallet_password: &[u8],
voting_keystore_password: &[u8],
withdrawal_keystore_password: &[u8],
) -> Result<ValidatorKeystores, Error> {
let keystores = self.wallet.next_validator(
wallet_password,
voting_keystore_password,
withdrawal_keystore_password,
)?;
update(&self.wallet_dir, &self.wallet)?;
Ok(keystores)
}
}