Don't keep the index repository open long term

src/docbuilder/queue.rs

@@ -12,7 +12,8 @@ impl DocBuilder {
     /// Returns the number of crates added
     pub fn get_new_crates(&mut self) -> Result<usize> {
         let conn = connect_db()?;
-        let (mut changes, oid) = self.index.diff().peek_changes()?;
+        let diff = self.index.diff()?;
+        let (mut changes, oid) = diff.peek_changes()?;
         let mut crates_added = 0;
 
         // I believe this will fix ordering of queue if we get more than one crate from changes
@@ -58,7 +59,7 @@ impl DocBuilder {
             }
         }
 
-        self.index.diff().set_last_seen_reference(oid)?;
+        diff.set_last_seen_reference(oid)?;
 
         Ok(crates_added)
     }

src/index/mod.rs

@@ -4,11 +4,11 @@ use url::Url;
 
 use self::api::Api;
 use crate::error::Result;
+use failure::ResultExt;
 
 pub(crate) mod api;
 
 pub(crate) struct Index {
-    diff: crates_index_diff::Index,
     path: PathBuf,
     api: Api,
 }
@@ -41,14 +41,19 @@ fn load_config(repo: &git2::Repository) -> Result<IndexConfig> {
 impl Index {
     pub(crate) fn new(path: impl AsRef<Path>) -> Result<Self> {
         let path = path.as_ref().to_owned();
-        let diff = crates_index_diff::Index::from_path_or_cloned(&path)?;
-        let config = load_config(diff.repository())?;
-        let api = Api::new(config.api)?;
-        Ok(Self { diff, path, api })
+        // This initializes the repository, then closes it afterwards to avoid leaking file descriptors.
+        // See https://github.com/rust-lang/docs.rs/pull/847
+        let diff = crates_index_diff::Index::from_path_or_cloned(&path)
+            .context("initialising registry index repository")?;
+        let config = load_config(diff.repository()).context("loading registry config")?;
+        let api = Api::new(config.api).context("initialising registry api client")?;
+        Ok(Self { path, api })
     }
 
-    pub(crate) fn diff(&self) -> &crates_index_diff::Index {
-        &self.diff
+    pub(crate) fn diff(&self) -> Result<crates_index_diff::Index> {
+        let diff = crates_index_diff::Index::from_path_or_cloned(&self.path)
+            .context("re-opening registry index for diff")?;
+        Ok(diff)
     }
 
     pub(crate) fn api(&self) -> &Api {