feat(tvix/store): add directoryservice r/5912

This adds a DirectoryService trait, and an implementation for it using
sled, and one using a HashMap.

Change-Id: Ida61524b2ca949e1b3a78089a5aa7d9f9800c8d7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8093
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>

1 files changed, 84 insertions, 0 deletions

diff --git a/tvix/store/src/directoryservice/sled.rs b/tvix/store/src/directoryservice/sled.rs
new file mode 100644
index 0000000000..caa78615d3
--- /dev/null
+++ b/tvix/store/src/directoryservice/sled.rs
@@ -0,0 +1,84 @@
+use crate::proto::Directory;
+use crate::{proto, Error};
+use data_encoding::BASE64;
+use prost::Message;
+use std::path::PathBuf;
+use tracing::{instrument, warn};
+
+use super::DirectoryService;
+
+#[derive(Clone)]
+pub struct SledDirectoryService {
+    db: sled::Db,
+}
+
+impl SledDirectoryService {
+    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 })
+    }
+}
+
+impl DirectoryService for SledDirectoryService {
+    // TODO: change api to only be by digest
+    #[instrument(name = "SledDirectoryService::get", skip(self, by_what))]
+    fn get(
+        &self,
+        by_what: &proto::get_directory_request::ByWhat,
+    ) -> Result<Option<proto::Directory>, Error> {
+        match by_what {
+            proto::get_directory_request::ByWhat::Digest(digest) => {
+                match self.db.get(digest) {
+                    // The directory was not found, return
+                    Ok(None) => Ok(None),
+
+                    // The directory was found, try to parse the data as Directory message
+                    Ok(Some(data)) => match Directory::decode(&*data) {
+                        Ok(directory) => {
+                            // Validate the retrieved Directory indeed has the
+                            // digest we expect it to have, to detect corruptions.
+                            let actual_digest = directory.digest();
+                            if actual_digest.as_slice() != digest {
+                                return Err(Error::StorageError(format!(
+                                    "requested directory with digest {}, but got {}",
+                                    BASE64.encode(digest),
+                                    BASE64.encode(&actual_digest)
+                                )));
+                            }
+
+                            Ok(Some(directory))
+                        }
+                        Err(e) => {
+                            warn!("unable to parse directory {}: {}", BASE64.encode(digest), e);
+                            Err(Error::StorageError(e.to_string()))
+                        }
+                    },
+                    // some storage error?
+                    Err(e) => Err(Error::StorageError(e.to_string())),
+                }
+            }
+        }
+    }
+
+    #[instrument(name = "SledDirectoryService::put", skip(self, directory), fields(directory.digest = BASE64.encode(&directory.digest())))]
+    fn put(&self, directory: proto::Directory) -> Result<Vec<u8>, Error> {
+        let digest = directory.digest();
+
+        // validate the directory itself.
+        if let Err(e) = directory.validate() {
+            return Err(Error::InvalidRequest(format!(
+                "directory {} failed validation: {}",
+                BASE64.encode(&digest),
+                e,
+            )));
+        }
+        // store it
+        let result = self.db.insert(&digest, directory.encode_to_vec());
+        if let Err(e) = result {
+            return Err(Error::StorageError(e.to_string()));
+        }
+        Ok(digest)
+    }
+}