agent: Add PullImage endpoint

This commit adds the PullImge endpoint to the agent
and the agent-ctl command to test it.

Fixes: #2509

Signed-off-by: Georgina Kinge <georgina.kinge@ibm.com>
Co-authored-by: stevenhorsman <steven@uk.ibm.com>

src/agent/protocols/protos/agent.proto

@@ -67,6 +67,7 @@ service AgentService {
 	rpc CopyFile(CopyFileRequest) returns (google.protobuf.Empty);
 	rpc GetOOMEvent(GetOOMEventRequest) returns (OOMEvent);
 	rpc AddSwap(AddSwapRequest) returns (google.protobuf.Empty);
+	rpc PullImage(PullImageRequest) returns (google.protobuf.Empty);
 }
 
 message CreateContainerRequest {
@@ -513,3 +514,8 @@ message GetMetricsRequest {}
 message Metrics {
 	string metrics = 1;
 }
+
+message PullImageRequest {
+	string image = 1;
+	string container_id = 2;
+}

src/agent/src/rpc.rs

@@ -11,6 +11,7 @@ use tokio::sync::Mutex;
 use std::ffi::CString;
 use std::io;
 use std::path::Path;
+use std::process::ExitStatus;
 use std::sync::Arc;
 use ttrpc::{
     self,
@@ -78,6 +79,8 @@ use std::path::PathBuf;
 
 const CONTAINER_BASE: &str = "/run/kata-containers";
 const MODPROBE_PATH: &str = "/sbin/modprobe";
+const SKOPEO_PATH: &str = "/usr/bin/skopeo";
+const UMOCI_PATH: &str = "/usr/local/bin/umoci";
 
 // Convenience macro to obtain the scope logger
 macro_rules! sl {
@@ -675,6 +678,21 @@ impl protocols::agent_ttrpc::AgentService for AgentService {
             .map_err(|e| ttrpc_error(ttrpc::Code::INTERNAL, e.to_string()))
     }
 
+    async fn pull_image(
+        &self,
+        _ctx: &TtrpcContext,
+        req: protocols::agent::PullImageRequest,
+    ) -> ttrpc::Result<protocols::empty::Empty> {
+        let image = req.get_image();
+        let cid = req.get_container_id();
+
+        pull_image_from_registry(image, cid)
+            .map_err(|e| ttrpc_error(ttrpc::Code::INTERNAL, e.to_string()))?;
+        unpack_image(cid).map_err(|e| ttrpc_error(ttrpc::Code::INTERNAL, e.to_string()))?;
+
+        Ok(Empty::new())
+    }
+
     async fn pause_container(
         &self,
         ctx: &TtrpcContext,
@@ -1697,6 +1715,76 @@ fn load_kernel_module(module: &protocols::agent::KernelModule) -> Result<()> {
     }
 }
 
+fn pull_image_from_registry(image: &str, cid: &str) -> Result<()> {
+    let source_image = format!("{}{}", "docker://", image);
+
+    let manifest_path = format!("/tmp/{}/image_manifest", cid);
+    let target_path_manifest = format!("dir://{}", manifest_path);
+
+    // Define the target transport and path for the OCI image, without signature
+    let oci_path = format!("/tmp/{}/image_oci:latest", cid);
+    let target_path_oci = format!("oci://{}", oci_path);
+
+    fs::create_dir_all(&manifest_path)?;
+    fs::create_dir_all(&oci_path)?;
+
+    let status: ExitStatus = Command::new(SKOPEO_PATH)
+        .arg("copy")
+        .arg(source_image)
+        .arg(&target_path_manifest)
+        .status()?;
+
+    if !status.success() {
+        return Err(anyhow!(format!("failed to pull image: {:?}", status)));
+    }
+
+    // Copy image from one local file-system to another
+    // Resulting image is still stored in manifest format, but no longer includes the signature
+    // The image with a signature can then be unpacked into a bundle
+    let status: ExitStatus = Command::new(SKOPEO_PATH)
+        .arg("copy")
+        .arg(&target_path_manifest)
+        .arg(&target_path_oci)
+        .arg("--remove-signatures")
+        .status()?;
+
+    if !status.success() {
+        return Err(anyhow!(format!("failed to copy image: {:?}", status)));
+    }
+
+    // To save space delete the manifest.
+    // TODO LATER - when verify image is added, this will need moving the end of that, if required
+    fs::remove_dir_all(&manifest_path)?;
+    Ok(())
+}
+
+fn unpack_image(cid: &str) -> Result<()> {
+    let source_path_oci = format!("/tmp/{}/image_oci:latest", cid);
+    let target_path_bundle = format!("{}{}{}", CONTAINER_BASE, "/", cid);
+
+    info!(sl!(), "cid is {:?}", cid);
+    info!(sl!(), "target_path_bundle is {:?}", target_path_bundle);
+
+    // Unpack image
+
+    let status: ExitStatus = Command::new(UMOCI_PATH)
+        .arg("--verbose")
+        .arg("unpack")
+        .arg("--image")
+        .arg(&source_path_oci)
+        .arg(&target_path_bundle)
+        .status()?;
+
+    if !status.success() {
+        return Err(anyhow!(format!("failed to unpack image: {:?}", status)));
+    }
+
+    // To save space delete the oci image after unpack
+    fs::remove_dir_all(&source_path_oci)?;
+
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

tools/agent-ctl/src/client.rs

@@ -258,6 +258,11 @@ static AGENT_CMDS: &'static [AgentCmd] = &[
         st: ServiceType::Agent,
         fp: agent_cmd_container_write_stdin,
     },
+    AgentCmd {
+        name: "PullImage",
+        st: ServiceType::Agent,
+        fp: agent_cmd_pull_image,
+    },
 ];
 
 static BUILTIN_CMDS: &'static [BuiltinCmd] = &[
@@ -1933,6 +1938,35 @@ fn agent_cmd_sandbox_mem_hotplug_by_probe(
     Ok(())
 }
 
+fn agent_cmd_pull_image(
+    ctx: &Context,
+    client: &AgentServiceClient,
+    _health: &HealthClient,
+    options: &mut Options,
+    args: &str,
+) -> Result<()> {
+    let mut req = PullImageRequest::default();
+
+    let ctx = clone_context(ctx);
+
+    let image = utils::get_option("image", options, args);
+    let cid = utils::get_option("cid", options, args);
+
+    req.set_image(image);
+    req.set_container_id(cid);
+
+    debug!(sl!(), "sending request"; "request" => format!("{:?}", req));
+
+    let reply = client
+        .pull_image(ctx, &req)
+        .map_err(|e| anyhow!("{:?}", e).context(ERR_API_FAILED))?;
+
+    info!(sl!(), "response received";
+        "response" => format!("{:?}", reply));
+
+    Ok(())
+}
+
 #[inline]
 fn builtin_cmd_repeat(_args: &str) -> (Result<()>, bool) {
     // XXX: NOP implementation. Due to the way repeat has to work, providing a

tools/osbuilder/rootfs-builder/fedora/Dockerfile.in

@@ -30,7 +30,7 @@ RUN dnf -y update && dnf install -y \
     m4 \
     make \
     pkgconfig \
-    redhat-release \
+    fedora-release-common \
     sed \
     systemd \
     tar \

tools/osbuilder/rootfs-builder/fedora/config.sh

@@ -5,7 +5,7 @@
 
 OS_NAME="Fedora"
 
-OS_VERSION=${OS_VERSION:-30}
+OS_VERSION=${OS_VERSION:-34}
 
 MIRROR_LIST="https://mirrors.fedoraproject.org/metalink?repo=fedora-${OS_VERSION}&arch=\$basearch"