store: Only print "Fetching bound image" if it's not there

Also print how many bound images we have, since it's interesting
and relevant information.

Signed-off-by: Colin Walters <walters@verbum.org>

lib/src/boundimage.rs

@@ -5,6 +5,8 @@
 //! pre-pulled (and in the future, pinned) before a new image root
 //! is considered ready.
 
+use std::num::NonZeroUsize;
+
 use anyhow::{Context, Result};
 use camino::Utf8Path;
 use cap_std_ext::cap_std::fs::Dir;
@@ -145,16 +147,22 @@ fn parse_container_file(file_contents: &tini::Ini) -> Result<BoundImage> {
 #[context("Pulling bound images")]
 pub(crate) async fn pull_images(sysroot: &Storage, bound_images: Vec<BoundImage>) -> Result<()> {
     tracing::debug!("Pulling bound images: {}", bound_images.len());
-    // Only initialize the image storage if we have images to pull
-    let imgstore = if !bound_images.is_empty() {
-        sysroot.get_ensure_imgstore()?
-    } else {
+    // Yes, the usage of NonZeroUsize here is...maybe odd looking, but I find
+    // it an elegant way to divide (empty vector, non empty vector) since
+    // we want to print the length too below.
+    let Some(n) = NonZeroUsize::new(bound_images.len()) else {
         return Ok(());
     };
-    //TODO: do this in parallel
+    // Only do work like initializing the image storage if we have images to pull.
+    let imgstore = sysroot.get_ensure_imgstore()?;
+    // TODO: do this in parallel
     for bound_image in bound_images {
         let image = &bound_image.image;
-        let desc = format!("Updating bound image: {image}");
+        if imgstore.exists(image).await? {
+            tracing::debug!("Bound image already present: {image}");
+            continue;
+        }
+        let desc = format!("Fetching bound image: {image}");
         crate::utils::async_task_with_spinner(&desc, async move {
             imgstore
                 .pull(&bound_image.image, PullMode::IfNotExists)
@@ -163,6 +171,8 @@ pub(crate) async fn pull_images(sysroot: &Storage, bound_images: Vec<BoundImage>
         .await?;
     }
 
+    println!("Bound images stored: {n}");
+
     Ok(())
 }
 

lib/src/imgstorage.rs

@@ -245,17 +245,21 @@ impl Storage {
         Ok(garbage)
     }
 
+    /// Return true if the image exists in the storage.
+    pub(crate) async fn exists(&self, image: &str) -> Result<bool> {
+        // Sadly https://docs.rs/containers-image-proxy/latest/containers_image_proxy/struct.ImageProxy.html#method.open_image_optional
+        // doesn't work with containers-storage yet
+        let mut cmd = AsyncCommand::from(self.new_image_cmd()?);
+        cmd.args(["exists", image]);
+        Ok(cmd.status().await?.success())
+    }
+
     /// Fetch the image if it is not already present; return whether
     /// or not the image was fetched.
     pub(crate) async fn pull(&self, image: &str, mode: PullMode) -> Result<bool> {
         match mode {
             PullMode::IfNotExists => {
-                // Sadly https://docs.rs/containers-image-proxy/latest/containers_image_proxy/struct.ImageProxy.html#method.open_image_optional
-                // doesn't work with containers-storage yet
-                let mut cmd = AsyncCommand::from(self.new_image_cmd()?);
-                cmd.args(["exists", image]);
-                let exists = cmd.status().await?.success();
-                if exists {
+                if self.exists(image).await? {
                     tracing::debug!("Image is already present: {image}");
                     return Ok(false);
                 }