Merge pull request #91 from DeterminateSystems/why-io-error

Why io error

gha-cache/src/api.rs

@@ -75,8 +75,8 @@ pub enum Error {
         info: ApiErrorInfo,
     },
 
-    #[error("I/O error: {0}")]
-    IoError(#[from] std::io::Error),
+    #[error("I/O error: {0}, context: {1}")]
+    IoError(std::io::Error, String),
 
     #[error("Too many collisions")]
     TooManyCollisions,
@@ -345,8 +345,9 @@ impl Api {
         let mut futures = Vec::new();
         loop {
             let buf = BytesMut::with_capacity(CHUNK_SIZE);
-            let chunk = read_chunk_async(&mut stream, buf).await?;
-
+            let chunk = read_chunk_async(&mut stream, buf)
+                .await
+                .map_err(|e| Error::IoError(e, "Reading a chunk during upload".to_string()))?;
             if chunk.is_empty() {
                 offset += chunk.len();
                 break;
@@ -368,7 +369,10 @@ impl Api {
                 let url = self.construct_url(&format!("caches/{}", allocation.0 .0));
 
                 tokio::task::spawn(async move {
-                    let permit = concurrency_limit.acquire().await.unwrap();
+                    let permit = concurrency_limit
+                        .acquire()
+                        .await
+                        .expect("failed to acquire concurrency semaphore permit");
 
                     tracing::trace!(
                         "Starting uploading chunk {}-{}",
@@ -410,7 +414,9 @@ impl Api {
         future::join_all(futures)
             .await
             .into_iter()
-            .try_for_each(|join_result| join_result.unwrap())?;
+            .try_for_each(|join_result| {
+                join_result.expect("failed collecting a join result during parallel upload")
+            })?;
 
         tracing::debug!("Received all chunks for cache {:?}", allocation.0);
 

magic-nix-cache/src/api.rs

@@ -112,7 +112,8 @@ async fn workflow_finish(
 
     // NOTE(cole-h): see `init_logging`
     if let Some(logfile) = &state.logfile {
-        let logfile_contents = std::fs::read_to_string(logfile)?;
+        let logfile_contents = std::fs::read_to_string(logfile)
+            .map_err(|e| crate::error::Error::Io(e, format!("Reading {}", logfile.display())))?;
         println!("Every log line throughout the lifetime of the program:");
         println!("\n{logfile_contents}\n");
     }

magic-nix-cache/src/error.rs

@@ -19,8 +19,8 @@ pub enum Error {
     #[error("Bad Request")]
     BadRequest,
 
-    #[error("I/O error: {0}")]
-    Io(#[from] std::io::Error),
+    #[error("I/O error: {0}. Context: {1}")]
+    Io(std::io::Error, String),
 
     #[error("GHA cache is disabled")]
     GHADisabled,

magic-nix-cache/src/gha.rs

@@ -72,7 +72,9 @@ impl GhaCache {
             self.channel_tx
                 .send(Request::Shutdown)
                 .expect("Cannot send shutdown message");
-            worker_result.await.unwrap()
+            worker_result
+                .await
+                .expect("failed to read result from gha worker")
         } else {
             Ok(())
         }
@@ -189,7 +191,7 @@ async fn upload_path(
 
     let narinfo = path_info_to_nar_info(store.clone(), &path_info, format!("nar/{}", nar_path))
         .to_string()
-        .unwrap();
+        .expect("failed to convert path into to nar info");
 
     tracing::debug!("Uploading '{}'", narinfo_path);
 
@@ -224,7 +226,17 @@ fn path_info_to_nar_info(store: Arc<NixStore>, path_info: &ValidPathInfo, url: S
         references: path_info
             .references
             .iter()
-            .map(|r| r.file_name().unwrap().to_str().unwrap().to_owned())
+            .map(|r| {
+                r.file_name()
+                    .and_then(|n| n.to_str())
+                    .unwrap_or_else(|| {
+                        panic!(
+                            "failed to convert nar_info reference to string: {}",
+                            r.display()
+                        )
+                    })
+                    .to_owned()
+            })
             .collect(),
         system: None,
         deriver: None,

magic-nix-cache/src/main.rs

@@ -392,8 +392,33 @@ async fn main_cli() -> Result<()> {
 
         tracing::debug!("Startup notification via file at {startup_notification_file_path:?}");
 
-        let mut notification_file = File::create(&startup_notification_file_path).await?;
-        notification_file.write_all(file_contents).await?;
+        if let Some(parent_dir) = startup_notification_file_path.parent() {
+            tokio::fs::create_dir_all(parent_dir)
+                .await
+                .with_context(|| {
+                    format!(
+                        "failed to create parent directory for startup notification file path: {}",
+                        startup_notification_file_path.display()
+                    )
+                })?;
+        }
+        let mut notification_file = File::create(&startup_notification_file_path)
+            .await
+            .with_context(|| {
+                format!(
+                    "failed to create startup notification file to path: {}",
+                    startup_notification_file_path.display()
+                )
+            })?;
+        notification_file
+            .write_all(file_contents)
+            .await
+            .with_context(|| {
+                format!(
+                    "failed to write startup notification file to path: {}",
+                    startup_notification_file_path.display()
+                )
+            })?;
 
         tracing::debug!("Created startup notification file at {startup_notification_file_path:?}");
     }
@@ -437,8 +462,16 @@ fn init_logging() -> Result<LogGuard> {
     let filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| {
         #[cfg(debug_assertions)]
         return EnvFilter::new("info")
-            .add_directive("magic_nix_cache=debug".parse().unwrap())
-            .add_directive("gha_cache=debug".parse().unwrap());
+            .add_directive(
+                "magic_nix_cache=debug"
+                    .parse()
+                    .expect("failed to parse magix_nix_cache directive"),
+            )
+            .add_directive(
+                "gha_cache=debug"
+                    .parse()
+                    .expect("failed to parse gha_cahce directive"),
+            );
 
         #[cfg(not(debug_assertions))]
         return EnvFilter::new("info");

magic-nix-cache/src/pbh.rs

@@ -164,9 +164,20 @@ pub async fn setup_legacy_post_build_hook(
                 &path.display().to_string(),
             ])
             .output()
-            .await?;
+            .await
+            .with_context(|| {
+                format!(
+                    "Running nix to add the post-build-hook to the store from {}",
+                    path.display()
+                )
+            })?;
         if res.status.success() {
-            tokio::fs::remove_file(path).await?;
+            tokio::fs::remove_file(&path).await.with_context(|| {
+                format!(
+                    "Cleaning up the temporary post-build-hook at {}",
+                    path.display()
+                )
+            })?;
             PathBuf::from(String::from_utf8_lossy(&res.stdout).trim())
         } else {
             path

magic-nix-cache/src/util.rs

@@ -11,9 +11,19 @@ use crate::error::Result;
 pub async fn get_store_paths(store: &NixStore) -> Result<HashSet<PathBuf>> {
     // FIXME: use the Nix API.
     let store_dir = store.store_dir();
-    let mut listing = tokio::fs::read_dir(store_dir).await?;
+    let mut listing = tokio::fs::read_dir(store_dir).await.map_err(|e| {
+        crate::error::Error::Io(
+            e,
+            format!("Enumerating store paths in {}", store_dir.display()),
+        )
+    })?;
     let mut paths = HashSet::new();
-    while let Some(entry) = listing.next_entry().await? {
+    while let Some(entry) = listing.next_entry().await.map_err(|e| {
+        crate::error::Error::Io(
+            e,
+            format!("Reading existing store paths from {}", store_dir.display()),
+        )
+    })? {
         let file_name = entry.file_name();
         let file_name = Path::new(&file_name);