container: Support JSON out for ManifestDiff

This will let higher level tools (Plasma Discover for example) more
easily read the output of `bootc update --check --json`.

lib/src/cli.rs

@@ -10,7 +10,7 @@ use camino::{Utf8Path, Utf8PathBuf};
 use cap_std::fs::Dir;
 use cap_std_ext::cap_std;
 use cap_std_ext::prelude::CapStdExtDirExt;
-use clap::{Parser, Subcommand};
+use clap::{Parser, Subcommand, builder::ArgPredicate};
 use fn_error_context::context;
 use io_lifetimes::AsFd;
 use ostree::{gio, glib};
@@ -178,6 +178,10 @@ pub(crate) enum ContainerOpts {
         /// Image reference, e.g. ostree-remote-image:someremote:registry:quay.io/exampleos/exampleos:latest
         #[clap(value_parser = parse_imgref)]
         imgref_new: OstreeImageReference,
+
+        /// Use JSON as output format.
+        #[clap(long)]
+        json: bool,
     },
 }
 
@@ -234,6 +238,10 @@ pub(crate) enum ContainerImageOpts {
         /// the new manifest.
         #[clap(long)]
         check: Option<Utf8PathBuf>,
+
+        /// Use JSON as output format. Only applies to the --check option.
+        #[clap(long, requires_if(ArgPredicate::IsPresent, "check"))]
+        json: bool,
     },
 
     /// Output metadata about an already stored container image.
@@ -717,6 +725,7 @@ async fn container_store(
     proxyopts: ContainerProxyOpts,
     quiet: bool,
     check: Option<Utf8PathBuf>,
+    json: bool
 ) -> Result<()> {
     let mut imp = ImageImporter::new(repo, imgref, proxyopts.into()).await?;
     let prep = match imp.prepare().await? {
@@ -739,7 +748,7 @@ async fn container_store(
     }
     if let Some(previous_state) = prep.previous_state.as_ref() {
         let diff = ManifestDiff::new(&previous_state.manifest, &prep.manifest);
-        diff.print();
+        diff.print(json);
     }
     print_layer_status(&prep);
     let printer = (!quiet).then(|| {
@@ -965,9 +974,10 @@ async fn run_from_opt(opt: Opt) -> Result<()> {
                     proxyopts,
                     quiet,
                     check,
+                    json,
                 } => {
                     let repo = parse_repo(&repo)?;
-                    container_store(&repo, &imgref, proxyopts, quiet, check).await
+                    container_store(&repo, &imgref, proxyopts, quiet, check, json).await
                 }
                 ContainerImageOpts::History { repo, imgref } => {
                     let repo = parse_repo(&repo)?;
@@ -1177,12 +1187,13 @@ async fn run_from_opt(opt: Opt) -> Result<()> {
             ContainerOpts::Compare {
                 imgref_old,
                 imgref_new,
+                json,
             } => {
                 let (manifest_old, _) = crate::container::fetch_manifest(&imgref_old).await?;
                 let (manifest_new, _) = crate::container::fetch_manifest(&imgref_new).await?;
                 let manifest_diff =
                     crate::container::ManifestDiff::new(&manifest_old, &manifest_new);
-                manifest_diff.print();
+                manifest_diff.print(json);
                 Ok(())
             }
         },

lib/src/container/mod.rs

@@ -28,6 +28,7 @@
 use anyhow::anyhow;
 use containers_image_proxy::oci_spec;
 use ostree::glib;
+use serde_json::json;
 
 use std::borrow::Cow;
 use std::collections::HashMap;
@@ -376,16 +377,34 @@ impl<'a> ManifestDiff<'a> {
 
 impl<'a> ManifestDiff<'a> {
     /// Prints the total, removed and added content between two OCI images
-    pub fn print(&self) {
-        let print_total = self.total;
-        let print_total_size = glib::format_size(self.total_size);
-        let print_n_removed = self.n_removed;
-        let print_removed_size = glib::format_size(self.removed_size);
-        let print_n_added = self.n_added;
-        let print_added_size = glib::format_size(self.added_size);
-        println!("Total new layers: {print_total:<4}  Size: {print_total_size}");
-        println!("Removed layers:   {print_n_removed:<4}  Size: {print_removed_size}");
-        println!("Added layers:     {print_n_added:<4}  Size: {print_added_size}");
+    pub fn print(&self, json: bool) {
+        if json {
+            let out = json!({
+                "total": {
+                  "count": self.total,
+                  "size": self.total_size
+                },
+                "removed": {
+                  "count": self.n_removed,
+                  "size": self.removed_size
+                },
+                "added": {
+                  "count": self.n_added,
+                  "size": self.added_size
+                }
+              });
+            println!("{}", out.to_string());
+        } else {
+            let print_total = self.total;
+            let print_total_size = glib::format_size(self.total_size);
+            let print_n_removed = self.n_removed;
+            let print_removed_size = glib::format_size(self.removed_size);
+            let print_n_added = self.n_added;
+            let print_added_size = glib::format_size(self.added_size);
+            println!("Total new layers: {print_total:<4}  Size: {print_total_size}");
+            println!("Removed layers:   {print_n_removed:<4}  Size: {print_removed_size}");
+            println!("Added layers:     {print_n_added:<4}  Size: {print_added_size}");
+        }
     }
 }