use super::{BlobReader, BlobService, BlobWriter};
use crate::{B3Digest, Error};
use std::{
io::{self, Cursor},
path::PathBuf,
};
use tracing::instrument;
#[derive(Clone)]
pub struct SledBlobService {
db: sled::Db,
}
impl SledBlobService {
pub fn new(p: PathBuf) -> Result<Self, sled::Error> {
let config = sled::Config::default().use_compression(true).path(p);
let db = config.open()?;
Ok(Self { db })
}
pub fn new_temporary() -> Result<Self, sled::Error> {
let config = sled::Config::default().temporary(true);
let db = config.open()?;
Ok(Self { db })
}
}
impl BlobService for SledBlobService {
/// Constructs a [SledBlobService] from the passed [url::Url]:
/// - scheme has to be `sled://`
/// - there may not be a host.
/// - a path to the sled needs to be provided (which may not be `/`).
fn from_url(url: &url::Url) -> Result<Self, Error> {
if url.scheme() != "sled" {
return Err(crate::Error::StorageError("invalid scheme".to_string()));
}
if url.has_host() {
return Err(crate::Error::StorageError(format!(
"invalid host: {}",
url.host().unwrap()
)));
}
// TODO: expose compression and other parameters as URL parameters, drop new and new_temporary?
if url.path().is_empty() {
Self::new_temporary().map_err(|e| Error::StorageError(e.to_string()))
} else if url.path() == "/" {
Err(crate::Error::StorageError(
"cowardly refusing to open / with sled".to_string(),
))
} else {
Self::new(url.path().into()).map_err(|e| Error::StorageError(e.to_string()))
}
}
#[instrument(skip(self), fields(blob.digest=%digest))]
fn has(&self, digest: &B3Digest) -> Result<bool, Error> {
match self.db.contains_key(digest.to_vec()) {
Ok(has) => Ok(has),
Err(e) => Err(Error::StorageError(e.to_string())),
}
}
#[instrument(skip(self), fields(blob.digest=%digest))]
fn open_read(&self, digest: &B3Digest) -> Result<Option<Box<dyn BlobReader>>, Error> {
match self.db.get(digest.to_vec()) {
Ok(None) => Ok(None),
Ok(Some(data)) => Ok(Some(Box::new(Cursor::new(data[..].to_vec())))),
Err(e) => Err(Error::StorageError(e.to_string())),
}
}
#[instrument(skip(self))]
fn open_write(&self) -> Box<dyn BlobWriter> {
Box::new(SledBlobWriter::new(self.db.clone()))
}
}
pub struct SledBlobWriter {
db: sled::Db,
/// Contains the buffer Vec and hasher, or None if already closed
writers: Option<(Vec<u8>, blake3::Hasher)>,
/// The digest that has been returned, if we successfully closed.
digest: Option<B3Digest>,
}
impl SledBlobWriter {
pub fn new(db: sled::Db) -> Self {
Self {
db,
writers: Some((Vec::new(), blake3::Hasher::new())),
digest: None,
}
}
}
impl io::Write for SledBlobWriter {
fn write(&mut self, b: &[u8]) -> io::Result<usize> {
match &mut self.writers {
None => Err(io::Error::new(
io::ErrorKind::NotConnected,
"already closed",
)),
Some((ref mut buf, ref mut hasher)) => {
let bytes_written = buf.write(b)?;
hasher.write(&b[..bytes_written])
}
}
}
fn flush(&mut self) -> io::Result<()> {
match &mut self.writers {
None => Err(io::Error::new(
io::ErrorKind::NotConnected,
"already closed",
)),
Some(_) => Ok(()),
}
}
}
impl BlobWriter for SledBlobWriter {
fn close(&mut self) -> Result<B3Digest, Error> {
if self.writers.is_none() {
match &self.digest {
Some(digest) => Ok(digest.clone()),
None => Err(crate::Error::StorageError(
"previously closed with error".to_string(),
)),
}
} else {
let (buf, hasher) = self.writers.take().unwrap();
// We know self.hasher is doing blake3 hashing, so this won't fail.
let digest = B3Digest::from_vec(hasher.finalize().as_bytes().to_vec()).unwrap();
// Only insert if the blob doesn't already exist.
if !self.db.contains_key(digest.to_vec()).map_err(|e| {
Error::StorageError(format!("Unable to check if we have blob {}: {}", digest, e))
})? {
// put buf in there. This will move buf out.
self.db
.insert(digest.to_vec(), buf)
.map_err(|e| Error::StorageError(format!("unable to insert blob: {}", e)))?;
}
self.digest = Some(digest.clone());
Ok(digest)
}
}
}
#[cfg(test)]
mod tests {
use tempfile::TempDir;
use super::BlobService;
use super::SledBlobService;
/// This uses a wrong scheme.
#[test]
fn test_invalid_scheme() {
let url = url::Url::parse("http://foo.example/test").expect("must parse");
assert!(SledBlobService::from_url(&url).is_err());
}
/// This uses the correct scheme, and doesn't specify a path (temporary sled).
#[test]
fn test_valid_scheme_temporary() {
let url = url::Url::parse("sled://").expect("must parse");
assert!(SledBlobService::from_url(&url).is_ok());
}
/// This sets the path to a location that doesn't exist, which should fail (as sled doesn't mkdir -p)
#[test]
fn test_nonexistent_path() {
let tmpdir = TempDir::new().unwrap();
let mut url = url::Url::parse("sled://foo.example").expect("must parse");
url.set_path(tmpdir.path().join("foo").join("bar").to_str().unwrap());
assert!(SledBlobService::from_url(&url).is_err());
}
/// This uses the correct scheme, and specifies / as path (which should fail
// for obvious reasons)
#[test]
fn test_invalid_path_root() {
let url = url::Url::parse("sled:///").expect("must parse");
assert!(SledBlobService::from_url(&url).is_err());
}
/// This uses the correct scheme, and sets a tempdir as location.
#[test]
fn test_valid_scheme_path() {
let tmpdir = TempDir::new().unwrap();
let mut url = url::Url::parse("sled://").expect("must parse");
url.set_path(tmpdir.path().to_str().unwrap());
assert!(SledBlobService::from_url(&url).is_ok());
}
/// This sets a host, rather than a path, which should fail.
#[test]
fn test_invalid_host() {
let url = url::Url::parse("sled://foo.example").expect("must parse");
assert!(SledBlobService::from_url(&url).is_err());
}
/// This sets a host AND a valid path, which should fail
#[test]
fn test_invalid_host_and_path() {
let tmpdir = TempDir::new().unwrap();
let mut url = url::Url::parse("sled://foo.example").expect("must parse");
url.set_path(tmpdir.path().to_str().unwrap());
assert!(SledBlobService::from_url(&url).is_err());
}
}