snap: Create a task for installing docker

Let's have the docker installation / configuration as part of its own
task, which can be set as a dependency of other tasks whcih may or may
not depend on docker.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

snap/snapcraft.yaml

@@ -82,8 +82,36 @@ parts:
       fi
       rustup component add rustfmt
 
+  docker:
+    after: [metadata]
+    plugin: nil
+    prime:
+      - -*
+    build-packages:
+      - curl
+    override-build: |
+      source "${SNAPCRAFT_PROJECT_DIR}/snap/local/snap-common.sh"
+
+      sudo apt-get -y update
+      sudo apt-get -y install ca-certificates curl gnupg lsb-release
+      curl -fsSL https://download.docker.com/linux/ubuntu/gpg |\
+          sudo gpg --batch --yes --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
+      distro_codename=$(lsb_release -cs)
+      echo "deb [arch=${dpkg_arch} signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu ${distro_codename} stable" |\
+          sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
+      sudo apt-get -y update
+      sudo apt-get -y install docker-ce docker-ce-cli containerd.io
+
+      echo "Unmasking docker service"
+      sudo -E systemctl unmask docker.service || true
+      sudo -E systemctl unmask docker.socket || true
+      echo "Adding $USER into docker group"
+      sudo -E gpasswd -a $USER docker
+      echo "Starting docker"
+      sudo -E systemctl start docker || true
+
   image:
-    after: [godeps, qemu, kernel]
+    after: [godeps, docker, qemu, kernel]
     plugin: nil
     build-packages:
       - docker.io
@@ -107,14 +135,6 @@ parts:
       # Copy yq binary. It's used in the container
       cp -a "${yq}" "${GOPATH}/bin/"
 
-      echo "Unmasking docker service"
-      sudo -E systemctl unmask docker.service || true
-      sudo -E systemctl unmask docker.socket || true
-      echo "Adding $USER into docker group"
-      sudo -E gpasswd -a $USER docker
-      echo "Starting docker"
-      sudo -E systemctl start docker || true
-
       cd "${kata_dir}/tools/osbuilder"
 
       # build image
@@ -333,22 +353,11 @@ parts:
 
   cloud-hypervisor:
     plugin: nil
-    after: [godeps]
+    after: [godeps, docker]
     override-build: |
       source "${SNAPCRAFT_PROJECT_DIR}/snap/local/snap-common.sh"
 
       if [ "${arch}" == "aarch64" ] || [ "${arch}" == "x86_64" ]; then
-          sudo apt-get -y update
-          sudo apt-get -y install ca-certificates curl gnupg lsb-release
-          curl -fsSL https://download.docker.com/linux/ubuntu/gpg |\
-              sudo gpg --batch --yes --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
-          distro_codename=$(lsb_release -cs)
-          echo "deb [arch=${dpkg_arch} signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu ${distro_codename} stable" |\
-              sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
-          sudo apt-get -y update
-          sudo apt-get -y install docker-ce docker-ce-cli containerd.io
-          sudo systemctl start docker.socket
-
           cd "${SNAPCRAFT_PROJECT_DIR}"
           sudo -E NO_TTY=true make cloud-hypervisor-tarball