reinstall: Ensure podman is installed

Fixes #1104

Make the podman dependency of system-reinstall-bootc optional

* Change the spec file to recommend podman instead of requiring it (this
  will make it more palatable to have this package included in distros
  by default)

* Now that podman is only recommended, the system-reinstall-bootc binary
  must check whether podman is installed and try to install it. This is
  done by launching the install-podman script that is included with the
  system-reinstall-bootc RPM. The exact location where
  system-reinstall-bootc will look for this script is defined in the
  build environment variable `SYSTEM_REINSTALL_BOOTC_INSTALL_PODMAN_PATH`

Signed-off-by: Omer Tuchfeld <[email protected]>

Author: omertuc

Cargo.lock

@@ -65,12 +65,14 @@ Provides: ostree-cli(ostree-container)
 # (-n because we don't want the subpackage name to start with bootc-)
 %package -n system-reinstall-bootc
 Summary: Utility to reinstall the current system using bootc
-Requires: podman
+Recommends: podman
 # The reinstall subpackage intentionally does not require bootc, as it pulls in many unnecessary dependencies
 
 %description -n system-reinstall-bootc
 This package provides a utility to simplify reinstalling the current system to a given bootc image.
 
+%global system_reinstall_bootc_install_podman_path %{_prefix}/lib/system-reinstall-bootc/install-podman
+
 %prep
 %autosetup -p1 -a1
 # Default -v vendor config doesn't support non-crates.io deps (i.e. git)
@@ -89,6 +91,7 @@ rm vendor-config.toml
 
 # Build the system reinstallation CLI binary
 %global cargo_args -p system-reinstall-bootc
+export SYSTEM_REINSTALL_BOOTC_INSTALL_PODMAN_PATH=%{system_reinstall_bootc_install_podman_path}
 %cargo_build
 
 %cargo_vendor_manifest
@@ -102,6 +105,12 @@ sed -i -e '/https:\/\//d' cargo-vendor.txt
 %if %{with ostree_ext}
 make install-ostree-hooks DESTDIR=%{?buildroot}
 %endif
+mkdir -p %{buildroot}/%{dirname:%{system_reinstall_bootc_install_podman_path}}
+cat >%{?buildroot}/%{system_reinstall_bootc_install_podman_path} <<EOF
+#!/bin/bash
+exec dnf -y install podman
+EOF
+chmod +x %{?buildroot}/%{system_reinstall_bootc_install_podman_path}
 
 %if %{with check}
 %check
@@ -126,6 +135,7 @@ make install-ostree-hooks DESTDIR=%{?buildroot}
 
 %files -n system-reinstall-bootc
 %{_bindir}/system-reinstall-bootc
+%{system_reinstall_bootc_install_podman_path}
 
 %changelog
 %autochangelog

contrib/packaging/bootc.spec

@@ -26,6 +26,7 @@ serde_json = { workspace = true }
 serde_yaml = "0.9.22"
 tracing = { workspace = true }
 uzers = "0.12.1"
+which = "7.0.2"
 
 [lints]
 workspace = true

system-reinstall-bootc/Cargo.toml

@@ -38,6 +38,10 @@ fn run() -> Result<()> {
 
     prompt::temporary_developer_protection_prompt()?;
 
+    // At this poihnt, the user has already given us permission to reinstall their system, so we
+    // feel confident with just installing podman without any further user interaction.
+    podman::ensure_podman_installed()?;
+
     reinstall_podman_command
         .run_with_cmd_context()
         .context("running reinstall command")?;

system-reinstall-bootc/src/main.rs

@@ -1,7 +1,9 @@
-use std::process::Command;
-
 use super::ROOT_KEY_MOUNT_POINT;
 use crate::users::UserKeys;
+use anyhow::{ensure, Context, Result};
+use bootc_utils::CommandRunExt;
+use std::process::Command;
+use which::which;
 
 pub(crate) fn command(image: &str, root_key: &Option<UserKeys>) -> Command {
     let mut podman_command_and_args = [
@@ -58,3 +60,42 @@ pub(crate) fn command(image: &str, root_key: &Option<UserKeys>) -> Command {
 
     command
 }
+
+/// Path to the podman installation script. Can be influenced by the build
+/// SYSTEM_REINSTALL_BOOTC_INSTALL_PODMAN_PATH parameter to override. Defaults
+/// to /usr/lib/system-reinstall-bootc/install-podman
+const fn podman_install_script_path() -> &'static str {
+    if let Some(path) = option_env!("SYSTEM_REINSTALL_BOOTC_INSTALL_PODMAN_PATH") {
+        path
+    } else {
+        "/usr/lib/system-reinstall-bootc/install-podman"
+    }
+}
+
+pub(crate) fn ensure_podman_installed() -> Result<()> {
+    if which("podman").is_ok() {
+        return Ok(());
+    }
+
+    tracing::warn!(
+        "Podman was not found on this system. It's required in order to install a bootc image."
+    );
+
+    ensure!(
+        which(podman_install_script_path()).is_ok(),
+        "Podman installation script {} not found, cannot automatically install podman. Please install it manually and try again.",
+        podman_install_script_path()
+    );
+
+    Command::new(podman_install_script_path())
+        .run_with_cmd_context()
+        .context("installing podman")?;
+
+    // Make sure the installation was actually successful
+    ensure!(
+        which("podman").is_ok(),
+        "podman still doesn't seem to be available, despite the installation. Please install it manually and try again."
+    );
+
+    Ok(())
+}