install: Introduce a script for installing Podman

Introduce a script for installing Podman in Ubuntu Focal, in
environments that may, or may not, have sudo installed.

Also, update our CircleCI configuration to use this script when
installing Podman.

.circleci/config.yml

@@ -1,6 +1,14 @@
 version: 2.1
 
 aliases:
+  - &provide-podman
+    name: Provide Podman in Ubuntu Focal
+    command: ./install/linux/install-podman-ubuntu-focal.sh --repo-only
+
+  - &install-podman
+    name: Install Podman in Ubuntu Focal
+    command: ./install/linux/install-podman-ubuntu-focal.sh
+
   - &install-dependencies-deb
     name: Install dependencies (deb)
     command: |
@@ -121,18 +129,8 @@ jobs:
     machine:
       image: ubuntu-2004:202111-01
     steps:
-      # https://www.atlantic.net/dedicated-server-hosting/how-to-install-and-use-podman-on-ubuntu-20-04/
-      - run:
-          name: Install podman on Ubuntu 20.04
-          command: |
-            export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true
-            source /etc/os-release
-            sudo sh -c "echo 'deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/xUbuntu_${VERSION_ID}/ /' > /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list"
-            wget -nv https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable/xUbuntu_${VERSION_ID}/Release.key -O- | sudo apt-key add -
-            sudo apt-get update -qq -y
-            sudo apt-get -qq --yes install podman
-            podman --version
       - checkout
+      - run: *install-podman
       - run:
           name: Install poetry dependencies
           command: |

install/linux/install-podman-ubuntu-focal.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+# Development script for installing Podman on Ubuntu Focal. Mainly to be used as
+# part of our CI pipelines, where we may install Podman on environments that
+# don't have sudo.
+
+set -e
+
+if [[ "$EUID" -ne 0 ]]; then
+    SUDO=sudo
+else
+    SUDO=
+fi
+
+provide() {
+    $SUDO apt-get update
+    $SUDO apt-get install curl wget gnupg2 -y
+    source /etc/os-release
+    $SUDO sh -c "echo 'deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/xUbuntu_${VERSION_ID}/ /' \
+      > /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list"
+    wget -nv https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable/xUbuntu_${VERSION_ID}/Release.key -O- \
+      | $SUDO apt-key add -
+    $SUDO apt-get update -qq -y
+}
+
+install() {
+    $SUDO apt-get -qq --yes install podman
+    podman --version
+}
+
+if [[ "$1" == "--repo-only" ]]; then
+    provide
+elif [[ "$1" == "" ]]; then
+    provide
+    install
+else
+    echo "Unexpected argument: $1"
+    echo "Usage: $0 [--repo-only]"
+    exit 1
+fi