encapsulate: Support setting arbitrary container config

Part of coreos/rpm-ostree#4701

Basically we should support setting arbitrary container configuration.

lib/src/cli.rs

@@ -17,7 +17,8 @@ use ostree::{gio, glib};
 use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::ffi::OsString;
-use std::io::{BufWriter, Write};
+use std::fs::File;
+use std::io::{BufReader, BufWriter, Write};
 use std::path::PathBuf;
 use std::process::Command;
 use tokio::sync::mpsc::Receiver;
@@ -138,6 +139,11 @@ pub(crate) enum ContainerOpts {
         /// Path to Docker-formatted authentication file.
         authfile: Option<PathBuf>,
 
+        /// Path to a JSON-formatted serialized container configuration; this is the
+        /// `config` property of https://github.com/opencontainers/image-spec/blob/main/config.md
+        #[clap(long)]
+        config: Option<Utf8PathBuf>,
+
         /// Propagate an OSTree commit metadata key to container label
         #[clap(name = "copymeta", long)]
         copy_meta_keys: Vec<String>,
@@ -660,16 +666,23 @@ async fn container_export(
     authfile: Option<PathBuf>,
     copy_meta_keys: Vec<String>,
     copy_meta_opt_keys: Vec<String>,
+    container_config: Option<Utf8PathBuf>,
     cmd: Option<Vec<String>>,
     compression_fast: bool,
 ) -> Result<()> {
     let config = Config {
         labels: Some(labels),
         cmd,
     };
+    let container_config = if let Some(container_config) = container_config {
+        serde_json::from_reader(File::open(container_config).map(BufReader::new)?)?
+    } else {
+        None
+    };
     let opts = crate::container::ExportOpts {
         copy_meta_keys,
         copy_meta_opt_keys,
+        container_config,
         authfile,
         skip_compression: compression_fast, // TODO rename this in the struct at the next semver break
         ..Default::default()
@@ -896,6 +909,7 @@ async fn run_from_opt(opt: Opt) -> Result<()> {
                 authfile,
                 copy_meta_keys,
                 copy_meta_opt_keys,
+                config,
                 cmd,
                 compression_fast,
             } => {
@@ -917,6 +931,7 @@ async fn run_from_opt(opt: Opt) -> Result<()> {
                     authfile,
                     copy_meta_keys,
                     copy_meta_opt_keys,
+                    config,
                     cmd,
                     compression_fast,
                 )

lib/src/container/encapsulate.rs

@@ -214,7 +214,7 @@ fn build_oci(
     let commit_meta = &commit_v.child_value(0);
     let commit_meta = glib::VariantDict::new(Some(commit_meta));
 
-    let mut ctrcfg = oci_image::Config::default();
+    let mut ctrcfg = opts.container_config.clone().unwrap_or_default();
     let mut imgcfg = oci_image::ImageConfiguration::default();
     imgcfg.set_created(Some(
         commit_timestamp.format("%Y-%m-%dT%H:%M:%SZ").to_string(),
@@ -381,6 +381,8 @@ pub struct ExportOpts<'m, 'o> {
     // TODO semver-break: remove this
     /// Use only the standard OCI version label
     pub no_legacy_version_label: bool,
+    /// Image runtime configuration that will be used as a base
+    pub container_config: Option<oci_image::Config>,
     /// A reference to the metadata for a previous build; used to optimize
     /// the packing structure.
     pub prior_build: Option<&'m oci_image::ImageManifest>,

lib/tests/it/main.rs

@@ -454,10 +454,15 @@ async fn impl_test_container_import_export(chunked: bool) -> Result<()> {
         })
         .transpose()?;
     let mut opts = ExportOpts::default();
+    let container_config = oci_spec::image::ConfigBuilder::default()
+        .stop_signal("SIGRTMIN+3")
+        .build()
+        .unwrap();
     opts.copy_meta_keys = vec!["buildsys.checksum".to_string()];
     opts.copy_meta_opt_keys = vec!["nosuchvalue".to_string()];
     opts.max_layers = std::num::NonZeroU32::new(PKGS_V0_LEN as u32);
     opts.contentmeta = contentmeta.as_ref();
+    opts.container_config = Some(container_config);
     let digest = ostree_ext::container::encapsulate(
         fixture.srcrepo(),
         fixture.testref(),
@@ -483,11 +488,10 @@ async fn impl_test_container_import_export(chunked: bool) -> Result<()> {
     let creation_time =
         chrono::NaiveDateTime::parse_from_str(cfg.created().as_deref().unwrap(), "%+").unwrap();
     assert_eq!(creation_time.timestamp(), 872879442);
+    let found_cfg = cfg.config().as_ref().unwrap();
     // unwrap.  Unwrap.  UnWrap.  UNWRAP!!!!!!!
     assert_eq!(
-        cfg.config()
-            .as_ref()
-            .unwrap()
+        found_cfg
             .cmd()
             .as_ref()
             .unwrap()
@@ -497,6 +501,7 @@ async fn impl_test_container_import_export(chunked: bool) -> Result<()> {
             .as_str(),
         "/usr/bin/bash"
     );
+    assert_eq!(found_cfg.stop_signal().as_deref().unwrap(), "SIGRTMIN+3");
 
     let n_chunks = if chunked { LAYERS_V0_LEN } else { 1 };
     assert_eq!(cfg.rootfs().diff_ids().len(), n_chunks);