use super::PathInfoService;
use crate::proto::PathInfo;
use data_encoding::BASE64;
use futures::{stream::BoxStream, StreamExt};
use prost::Message;
use redb::{Database, ReadableTable, TableDefinition};
use std::{path::PathBuf, sync::Arc};
use tokio_stream::wrappers::ReceiverStream;
use tonic::async_trait;
use tracing::{instrument, warn};
use tvix_castore::{
composition::{CompositionContext, ServiceBuilder},
Error,
};
const PATHINFO_TABLE: TableDefinition<[u8; 20], Vec<u8>> = TableDefinition::new("pathinfo");
/// PathInfoService implementation using redb under the hood.
/// redb stores all of its data in a single file with a K/V pointing from a path's output hash to
/// its corresponding protobuf-encoded PathInfo.
pub struct RedbPathInfoService {
// We wrap db in an Arc to be able to move it into spawn_blocking,
// as discussed in https://github.com/cberner/redb/issues/789
db: Arc<Database>,
}
impl RedbPathInfoService {
/// Constructs a new instance using the specified file system path for
/// storage.
pub async fn new(path: PathBuf) -> Result<Self, Error> {
if path == PathBuf::from("/") {
return Err(Error::StorageError(
"cowardly refusing to open / with redb".to_string(),
));
}
let db = tokio::task::spawn_blocking(|| -> Result<_, redb::Error> {
let db = redb::Database::create(path)?;
create_schema(&db)?;
Ok(db)
})
.await??;
Ok(Self { db: Arc::new(db) })
}
/// Constructs a new instance using the in-memory backend.
pub fn new_temporary() -> Result<Self, Error> {
let db =
redb::Database::builder().create_with_backend(redb::backends::InMemoryBackend::new())?;
create_schema(&db)?;
Ok(Self { db: Arc::new(db) })
}
}
/// Ensures all tables are present.
fn create_schema(db: &redb::Database) -> Result<(), redb::Error> {
// Opens a write transaction and calls open_table on PATHINFO_TABLE, which will
// create it if not present.
let txn = db.begin_write()?;
txn.open_table(PATHINFO_TABLE)?;
txn.commit()?;
Ok(())
}
#[async_trait]
impl PathInfoService for RedbPathInfoService {
#[instrument(level = "trace", skip_all, fields(path_info.digest = BASE64.encode(&digest)))]
async fn get(&self, digest: [u8; 20]) -> Result<Option<PathInfo>, Error> {
let db = self.db.clone();
tokio::task::spawn_blocking({
move || {
let txn = db.begin_read()?;
let table = txn.open_table(PATHINFO_TABLE)?;
match table.get(digest)? {
Some(pathinfo_bytes) => Ok(Some(
PathInfo::decode(pathinfo_bytes.value().as_slice()).map_err(|e| {
warn!(err=%e, "failed to decode stored PathInfo");
Error::StorageError(format!("failed to decode stored PathInfo: {}", e))
})?,
)),
None => Ok(None),
}
}
})
.await?
}
#[instrument(level = "trace", skip_all, fields(path_info.root_node = ?path_info.node))]
async fn put(&self, path_info: PathInfo) -> Result<PathInfo, Error> {
// Call validate on the received PathInfo message.
let store_path = path_info
.validate()
.map_err(|e| Error::InvalidRequest(format!("failed to validate PathInfo: {}", e)))?
.to_owned();
let path_info_encoded = path_info.encode_to_vec();
let db = self.db.clone();
tokio::task::spawn_blocking({
move || -> Result<(), Error> {
let txn = db.begin_write()?;
{
let mut table = txn.open_table(PATHINFO_TABLE)?;
table
.insert(store_path.digest(), path_info_encoded)
.map_err(|e| {
warn!(err=%e, "failed to insert PathInfo");
Error::StorageError(format!("failed to insert PathInfo: {}", e))
})?;
}
Ok(txn.commit()?)
}
})
.await??;
Ok(path_info)
}
fn list(&self) -> BoxStream<'static, Result<PathInfo, Error>> {
let db = self.db.clone();
let (tx, rx) = tokio::sync::mpsc::channel(50);
// Spawn a blocking task which writes all PathInfos to tx.
tokio::task::spawn_blocking({
move || -> Result<(), Error> {
let read_txn = db.begin_read()?;
let table = read_txn.open_table(PATHINFO_TABLE)?;
for elem in table.iter()? {
let elem = elem?;
tokio::runtime::Handle::current()
.block_on(tx.send(Ok(
PathInfo::decode(elem.1.value().as_slice()).map_err(|e| {
Error::InvalidRequest(format!("invalid PathInfo: {}", e))
})?,
)))
.map_err(|e| Error::StorageError(e.to_string()))?;
}
Ok(())
}
});
ReceiverStream::from(rx).boxed()
}
}
#[derive(serde::Deserialize)]
#[serde(deny_unknown_fields)]
pub struct RedbPathInfoServiceConfig {
is_temporary: bool,
#[serde(default)]
/// required when is_temporary = false
path: Option<PathBuf>,
}
impl TryFrom<url::Url> for RedbPathInfoServiceConfig {
type Error = Box<dyn std::error::Error + Send + Sync>;
fn try_from(url: url::Url) -> Result<Self, Self::Error> {
// redb doesn't support host, and a path can be provided (otherwise it'll live in memory only)
if url.has_host() {
return Err(Error::StorageError("no host allowed".to_string()).into());
}
Ok(if url.path().is_empty() {
RedbPathInfoServiceConfig {
is_temporary: true,
path: None,
}
} else {
RedbPathInfoServiceConfig {
is_temporary: false,
path: Some(url.path().into()),
}
})
}
}
#[async_trait]
impl ServiceBuilder for RedbPathInfoServiceConfig {
type Output = dyn PathInfoService;
async fn build<'a>(
&'a self,
_instance_name: &str,
_context: &CompositionContext,
) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
match self {
RedbPathInfoServiceConfig {
is_temporary: true,
path: None,
} => Ok(Arc::new(RedbPathInfoService::new_temporary()?)),
RedbPathInfoServiceConfig {
is_temporary: true,
path: Some(_),
} => Err(
Error::StorageError("Temporary RedbPathInfoService can not have path".into())
.into(),
),
RedbPathInfoServiceConfig {
is_temporary: false,
path: None,
} => Err(Error::StorageError("RedbPathInfoService is missing path".into()).into()),
RedbPathInfoServiceConfig {
is_temporary: false,
path: Some(path),
} => Ok(Arc::new(RedbPathInfoService::new(path.to_owned()).await?)),
}
}
}
