fix(snapshots): Chunk image uploads to avoid fd exhaustion and 413 errors

Uploading hundreds of images fails in two ways: all file handles are
opened upfront causing EMFILE (too many open files), and the objectstore
client batches everything into one HTTP request causing 413 Payload Too
Large from the server.

Split upload_images() into two phases: pre-process all images without
opening files (collision detection, hashing, metadata), then upload in
chunks of 100. This bounds both open file descriptors and HTTP request
payload size regardless of total image count.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: NicoHinderling

src/commands/build/snapshots.rs

@@ -9,7 +9,7 @@ use anyhow::{Context as _, Result};
 use clap::{Arg, ArgMatches, Command};
 use console::style;
 use itertools::Itertools as _;
-use log::{debug, info, warn};
+use log::{debug, warn};
 use objectstore_client::{ClientBuilder, ExpirationPolicy, Usecase};
 use rayon::prelude::*;
 use secrecy::ExposeSecret as _;
@@ -29,6 +29,7 @@ const EXPERIMENTAL_WARNING: &str =
 
 const IMAGE_EXTENSIONS: &[&str] = &["png", "jpg", "jpeg"];
 const MAX_PIXELS_PER_IMAGE: u64 = 40_000_000;
+const UPLOAD_BATCH_SIZE: usize = 100;
 
 pub fn make_command(command: Command) -> Command {
     command
@@ -283,6 +284,11 @@ fn read_sidecar_metadata(image_path: &Path) -> Result<HashMap<String, Value>> {
     })
 }
 
+struct PreparedImage {
+    path: PathBuf,
+    key: String,
+}
+
 fn upload_images(
     images: Vec<ImageInfo>,
     org: &str,
@@ -298,30 +304,28 @@ fn upload_images(
     let client = ClientBuilder::new(options.objectstore.url)
         .token({
             // TODO: replace with auth from `ObjectstoreUploadOptions` when appropriate
-            let auth = match authenticated_api.auth() {
+            match authenticated_api.auth() {
                 Auth::Token(token) => token.raw().expose_secret().to_owned(),
-            };
-            auth
+            }
         })
         .configure_reqwest(|r| r.connect_timeout(Duration::from_secs(10)))
         .build()?;
 
+    let scopes = options.objectstore.scopes;
+
+    let find_scope = |name: &str| {
+        scopes
+            .iter()
+            .find(|(k, _)| k == name)
+            .map(|(_, v)| v.clone())
+    };
+    let org_id = find_scope("org").context("Missing org in UploadOptions scope")?;
+    let project_id = find_scope("project").context("Missing project in UploadOptions scope")?;
+
     let mut scope = Usecase::new("preprod").scope();
-    let (mut org_id, mut project_id): (Option<String>, Option<String>) = (None, None);
-    for (key, value) in options.objectstore.scopes.into_iter() {
-        scope = scope.push(&key, value.clone());
-        if key == "org" {
-            org_id = Some(value);
-        } else if key == "project" {
-            project_id = Some(value);
-        }
+    for (key, value) in scopes {
+        scope = scope.push(&key, value);
     }
-    let Some(org_id) = org_id else {
-        anyhow::bail!("Missing org in UploadOptions scope");
-    };
-    let Some(project_id) = project_id else {
-        anyhow::bail!("Missing project in UploadOptions scope");
-    };
 
     let session = scope.session(&client)?;
 
@@ -330,10 +334,10 @@ fn upload_images(
         .build()
         .context("Failed to create tokio runtime")?;
 
-    let mut many_builder = session.many();
     let mut manifest_entries = HashMap::new();
     let mut collisions: HashMap<String, Vec<String>> = HashMap::new();
     let mut kept_paths = HashMap::new();
+    let mut uploads = Vec::with_capacity(images.len());
 
     let hashed_images: Vec<_> = images
         .into_par_iter()
@@ -361,21 +365,7 @@ fn upload_images(
             continue;
         }
 
-        let file = runtime
-            .block_on(tokio::fs::File::open(&image.path))
-            .with_context(|| {
-                format!("Failed to open image for upload: {}", image.path.display())
-            })?;
-
         let key = format!("{org_id}/{project_id}/{hash}");
-        info!("Queueing {} as {key}", image.relative_path.display());
-
-        many_builder = many_builder.push(
-            session
-                .put_file(file)
-                .key(&key)
-                .expiration_policy(expiration),
-        );
 
         let mut extra = read_sidecar_metadata(&image.path).unwrap_or_else(|err| {
             warn!("Error reading sidecar metadata, ignoring it instead: {err:#}");
@@ -384,47 +374,81 @@ fn upload_images(
         extra.insert("content_hash".to_owned(), serde_json::Value::String(hash));
 
         kept_paths.insert(image_file_name.clone(), relative_path);
+        uploads.push(PreparedImage {
+            path: image.path,
+            key,
+        });
         manifest_entries.insert(
             image_file_name,
             ImageMetadata::new(image.width, image.height, extra),
         );
     }
 
     if !collisions.is_empty() {
-        let mut details = String::new();
-        for (name, excluded_paths) in &collisions {
-            let mut all_paths = vec![kept_paths[name].as_str()];
-            all_paths.extend(excluded_paths.iter().map(|s| s.as_str()));
-            details.push_str(&format!("\n  {name}: {}", all_paths.join(", ")));
-        }
+        let details: String = collisions
+            .iter()
+            .map(|(name, excluded)| {
+                let kept = &kept_paths[name];
+                let all = std::iter::once(kept.as_str())
+                    .chain(excluded.iter().map(|s| s.as_str()))
+                    .join(", ");
+                format!("\n  {name}: {all}")
+            })
+            .collect();
         warn!("Some images share identical file names. Only the first occurrence of each is included:{details}");
     }
 
-    let result = runtime.block_on(async { many_builder.send().error_for_failures().await });
+    let total_count = uploads.len();
+    let total_batches = total_count.div_ceil(UPLOAD_BATCH_SIZE);
 
-    let uploaded_count = manifest_entries.len();
+    for (batch_idx, chunk) in uploads.chunks(UPLOAD_BATCH_SIZE).enumerate() {
+        debug!(
+            "Uploading batch {}/{total_batches} ({} images)",
+            batch_idx + 1,
+            chunk.len()
+        );
 
-    match result {
-        Ok(()) => {
-            println!(
-                "{} Uploaded {} image {}",
-                style(">").dim(),
-                style(uploaded_count).yellow(),
-                if uploaded_count == 1 { "file" } else { "files" }
+        let mut many_builder = session.many();
+        for prepared in chunk {
+            let file = runtime
+                .block_on(tokio::fs::File::open(&prepared.path))
+                .with_context(|| {
+                    format!(
+                        "Failed to open image for upload: {}",
+                        prepared.path.display()
+                    )
+                })?;
+
+            many_builder = many_builder.push(
+                session
+                    .put_file(file)
+                    .key(&prepared.key)
+                    .expiration_policy(expiration),
             );
-            Ok(manifest_entries)
         }
-        Err(errors) => {
+
+        let result = runtime.block_on(async { many_builder.send().error_for_failures().await });
+        if let Err(errors) = result {
+            let errors: Vec<_> = errors.collect();
             eprintln!("There were errors uploading images:");
-            let mut error_count = 0;
-            for error in errors {
-                let error = anyhow::Error::new(error);
+            for error in &errors {
                 eprintln!("  {}", style(format!("{error:#}")).red());
-                error_count += 1;
             }
-            anyhow::bail!("Failed to upload {error_count} out of {uploaded_count} images")
+            let error_count = errors.len();
+            let batch_num = batch_idx + 1;
+            anyhow::bail!(
+                "Failed to upload {error_count} images in batch {batch_num}/{total_batches}"
+            );
         }
     }
+
+    println!(
+        "{} Uploaded {} image {}",
+        style(">").dim(),
+        style(total_count).yellow(),
+        if total_count == 1 { "file" } else { "files" }
+    );
+    Ok(manifest_entries)
 }
 
 #[cfg(test)]