cuprate/storage/txpool/README.md
Boog900 44981f2b24
CI: add cargo hack (#170)
* add workflow

* fix errors

* fix workflow

* install dependencies

* fix more errors

* Update CONTRIBUTING.md

* Update CONTRIBUTING.md

Co-authored-by: hinto-janai <hinto.janai@protonmail.com>

* fix hack + enable it for cuprate-database

* move hack to main CI

* fix docs

* fix ci formatting

* fix txpool tests

* fix CONTRIBUTING.md formatting

* service -> tower::Service

* review fixes

* review fixes

* fix CI

---------

Co-authored-by: hinto-janai <hinto.janai@protonmail.com>
2024-11-01 20:22:14 +00:00

110 lines
3.2 KiB
Markdown

Cuprate's tx-pool database.
This documentation is mostly for practical usage of `cuprate_txpool`.
For a high-level overview, see the database section in
[Cuprate's architecture book](https://architecture.cuprate.org).
If you're looking for a database crate, consider using the lower-level
[`cuprate-database`](https://doc.cuprate.org/cuprate_database)
crate that this crate is built on-top of.
# Purpose
This crate does 3 things:
1. Uses [`cuprate_database`] as a base database layer
1. Implements various transaction pool related [operations](ops), [tables], and [types]
1. Exposes a [`tower::Service`] backed by a thread-pool
Each layer builds on-top of the previous.
As a user of `cuprate_txpool`, consider using the higher-level [`service`] module,
or at the very least the [`ops`] module instead of interacting with the `cuprate_database` traits directly.
# `cuprate_database`
Consider reading `cuprate_database`'s crate documentation before this crate, as it is the first layer.
If/when this crate needs is used, be sure to use the version that this crate re-exports, e.g.:
```rust
use cuprate_txpool::{
cuprate_database::RuntimeError,
};
```
This ensures the types/traits used from `cuprate_database` are the same ones used by `cuprate_txpool` internally.
# Feature flags
Different database backends are enabled by the feature flags:
- `heed` (LMDB)
- `redb`
The default is `heed`.
`tracing` is always enabled and cannot be disabled via feature-flag.
<!-- FIXME: tracing should be behind a feature flag -->
# Invariants when not using `service`
See [`cuprate_blockchain`](https://doc.cuprate.org/cuprate_blockchain), the invariants are the same.
# Examples
The below is an example of using `cuprate_txpool`'s
lowest API, i.e. using a mix of this crate and `cuprate_database`'s traits directly -
**this is NOT recommended.**
For examples of the higher-level APIs, see:
- [`ops`]
- [`service`]
```rust
use cuprate_txpool::{
cuprate_database::{
ConcreteEnv,
Env, EnvInner,
DatabaseRo, DatabaseRw, TxRo, TxRw,
},
config::ConfigBuilder,
tables::{Tables, TablesMut, OpenTables},
};
# fn main() -> Result<(), Box<dyn std::error::Error>> {
// Create a configuration for the database environment.
let tmp_dir = tempfile::tempdir()?;
let db_dir = tmp_dir.path().to_owned();
let config = ConfigBuilder::new()
.db_directory(db_dir.into())
.build();
// Initialize the database environment.
let env = cuprate_txpool::open(config)?;
// Open up a transaction + tables for writing.
let env_inner = env.env_inner();
let tx_rw = env_inner.tx_rw()?;
let mut tables = env_inner.open_tables_mut(&tx_rw)?;
// ⚠️ Write data to the tables directly.
// (not recommended, use `ops` or `service`).
const KEY_IMAGE: [u8; 32] = [88; 32];
const TX_HASH: [u8; 32] = [88; 32];
tables.spent_key_images_mut().put(&KEY_IMAGE, &TX_HASH)?;
// Commit the data written.
drop(tables);
TxRw::commit(tx_rw)?;
// Read the data, assert it is correct.
let tx_ro = env_inner.tx_ro()?;
let tables = env_inner.open_tables(&tx_ro)?;
let (key_image, tx_hash) = tables.spent_key_images().first()?;
assert_eq!(key_image, KEY_IMAGE);
assert_eq!(tx_hash, TX_HASH);
# Ok(())
}
```