radicle: temporary repository helper

It's possible that a temporary directory can be created on a different
mount, and when moved during a clone, creates an I/O error.

To prevent this, add a method to `Storage` which creates a temporary
directory and `Repository` with the path in the form
`<rid>.lock`.

This `.lock` path name can easily be skipped when listing
repositories. Further tooling can be added for detecting leftover
`.lock` directories if, for some reason, they were not cleaned up by
the `tempfile` crate.

Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett

radicle-node/src/runtime.rs

@@ -136,13 +136,7 @@ impl Runtime {
         let network = config.network;
         let rng = fastrand::Rng::new();
         let clock = LocalTime::now();
-        let storage = Storage::open(
-            home.storage(),
-            git::UserInfo {
-                alias: alias.clone(),
-                key: id,
-            },
-        )?;
+        let storage = Storage::open(home.storage(), git::UserInfo { alias, key: id })?;
         let address_db = node_dir.join(ADDRESS_DB_FILE);
         let routing_db = node_dir.join(ROUTING_DB_FILE);
         let tracking_db = node_dir.join(TRACKING_DB_FILE);
@@ -254,7 +248,6 @@ impl Runtime {
             scope,
             tracking_db,
             limit: FetchLimit::default(),
-            info: git::UserInfo { alias, key: nid },
             local: nid,
             expiry: worker::garbage::Expiry::default(),
         };

radicle-node/src/worker.rs

@@ -14,7 +14,7 @@ use radicle::identity::Id;
 use radicle::prelude::NodeId;
 use radicle::storage::refs::RefsAt;
 use radicle::storage::{ReadRepository, ReadStorage};
-use radicle::{crypto, git, Storage};
+use radicle::{crypto, Storage};
 use radicle_fetch::FetchLimit;
 
 use crate::runtime::{thread, Handle};
@@ -159,8 +159,6 @@ pub struct FetchConfig {
     pub tracking_db: PathBuf,
     /// Data limits when fetching from a remote.
     pub limit: FetchLimit,
-    /// Information of the local peer.
-    pub info: git::UserInfo,
     /// Public key of the local peer.
     pub local: crypto::PublicKey,
     /// Configuration for `git gc` garbage collection. Defaults to `1
@@ -281,7 +279,6 @@ impl Worker {
             scope,
             tracking_db,
             limit,
-            info,
             local,
             expiry,
         } = &self.fetch_config;
@@ -292,15 +289,7 @@ impl Worker {
         let tracked = radicle_fetch::Tracked::from_config(rid, &tracking)?;
         let blocked = radicle_fetch::BlockList::from_config(&tracking)?;
 
-        let handle = fetch::Handle::new(
-            rid,
-            *local,
-            info.clone(),
-            &self.storage,
-            tracked,
-            blocked,
-            channels,
-        )?;
+        let handle = fetch::Handle::new(rid, *local, &self.storage, tracked, blocked, channels)?;
         let result = handle.fetch(rid, &self.storage, *limit, remote, refs_at)?;
 
         if let Err(e) = garbage::collect(&self.storage, rid, *expiry) {

radicle-node/src/worker/fetch.rs

@@ -3,9 +3,7 @@ pub mod error;
 use std::collections::HashSet;
 
 use radicle::crypto::PublicKey;
-use radicle::git::UserInfo;
 use radicle::prelude::Id;
-use radicle::storage::git::Repository;
 use radicle::storage::refs::RefsAt;
 use radicle::storage::{ReadStorage as _, RefUpdate, WriteRepository as _};
 use radicle::Storage;
@@ -35,7 +33,6 @@ impl Handle {
     pub fn new(
         rid: Id,
         local: PublicKey,
-        info: UserInfo,
         storage: &Storage,
         tracked: Tracked,
         blocked: BlockList,
@@ -47,8 +44,7 @@ impl Handle {
             let handle = radicle_fetch::Handle::new(local, repo, tracked, blocked, channels)?;
             Ok(Handle::Pull { handle })
         } else {
-            let tmp = tempfile::tempdir()?;
-            let repo = Repository::create(tmp.path(), rid, &info)?;
+            let (repo, tmp) = storage.lock_repository(rid)?;
             let handle = radicle_fetch::Handle::new(local, repo, tracked, blocked, channels)?;
             Ok(Handle::Clone { handle, tmp })
         }

radicle/src/storage/git.rs

@@ -9,6 +9,7 @@ use std::{fs, io};
 
 use crypto::{Signer, Verified};
 use once_cell::sync::Lazy;
+use tempfile::TempDir;
 
 use crate::crypto::Unverified;
 use crate::git;
@@ -152,6 +153,27 @@ impl Storage {
         Ok(Self { path, info })
     }
 
+    /// Create a [`Repository`] in a temporary directory.
+    ///
+    /// N.b. it is important to keep the [`TempDir`] in scope while
+    /// using the [`Repository`]. If it is dropped, any action on the
+    /// `Repository` will fail.
+    pub fn lock_repository(&self, rid: Id) -> Result<(Repository, TempDir), RepositoryError> {
+        if self.contains(&rid)? {
+            return Err(Error::Io(io::Error::new(
+                io::ErrorKind::AlreadyExists,
+                format!("refusing to create '{}.lock'", rid),
+            ))
+            .into());
+        }
+        let tmp = tempfile::Builder::new()
+            .prefix(&rid.canonical())
+            .suffix(".lock")
+            .tempdir_in(self.path())
+            .map_err(Error::from)?;
+        Ok((Repository::create(tmp.path(), rid, &self.info)?, tmp))
+    }
+
     pub fn path(&self) -> &Path {
         self.path.as_path()
     }
@@ -170,6 +192,12 @@ impl Storage {
             if path.file_name().to_string_lossy().starts_with('.') {
                 continue;
             }
+            // Skip lock files.
+            if let Some(ext) = path.path().extension() {
+                if ext == "lock" {
+                    continue;
+                }
+            }
             let rid =
                 Id::try_from(path.file_name()).map_err(|_| Error::InvalidId(path.file_name()))?;