Improve save-portable-container-image

QUICKSTART.md

@@ -13,20 +13,10 @@ where we have scripts that do much of what is explained here.
 Requirements
 ------------
 
-To get started with Turandot you need `kubectl` access to a working Kubernetes
-cluster.
-
-For development work, [Minikube](https://minikube.sigs.k8s.io/docs/) is a quick way
-to get started. Just make sure to start Minikube with its registry add-on enabled:
+### Tools
 
-    minikube start --addons=registry ...
-
-Download the CLI Utilities
---------------------------
-
-[Download](https://github.com/tliron/turandot/releases) the latest binary release of
-Turandot. Specifically you'll need the `turandot` CLI utility (it's a self-contained
-executable).
+Download the binary release of [Turandot](https://github.com/tliron/turandot/releases).
+Specifically you'll need the `turandot` CLI utility (it's a self-contained executable).
 
 You will also need the [Reposure](https://reposure.puccini.cloud/) CLI utility in
 order to configure the registry that Turandot will use to store TOSCA service templates
@@ -36,6 +26,19 @@ Finally, we'll need the `puccini-csar` CLI utility from [Puccini](https://puccin
 in order to package our CSAR. It's generally useful to have Puccini available in
 order to validate and otherwise work with your TOSCA and CSAR.
 
+A few other tools used by the scripts: `podman` (or `docker`), `pigz` (or `gzip`),
+`zip`, `zipinfo`, `tar`.
+
+### Kubernetes Cluster
+
+To get started with Turandot you need `kubectl` access to a working Kubernetes
+cluster.
+
+For development work, [Minikube](https://minikube.sigs.k8s.io/docs/) is a quick way
+to get started. Just make sure to start Minikube with its registry add-on enabled:
+
+    minikube start --addons=registry ...
+
 The `turandot` and `reposure` utilities use the same local configuration you have for
 `kubectl`, and like `kubectl` they can accept a `--namespace` argument for selecting
 the namespace in which to work. To make commands more succinct in this guide let's set a
@@ -150,10 +153,6 @@ TOSCA artifact. The
 
     examples/hello-world/scripts/save-container-image
 
-The above script uses [Podman](https://podman.io/) to extract the tarball. If Podman is
-not available to you, you can use Docker instead. Simply replace all `podman` commands
-with `docker`.
-
 Next you'll use the [build-csar](examples/hello-world/scripts/build-csar) script to package
 the TOSCA topology template, profiles, and artifacts (including the container image
 tarball you created above) into a CSAR:

scripts/save-portable-container-image

@@ -30,9 +30,21 @@ function goodbye () {
 	old_goodbye $1
 }
 
+if command -v podman &> /dev/null; then
+	PODMAN=podman
+else
+	PODMAN=docker
+fi
+
+if command -v pigz &> /dev/null; then
+	GZIP=pigz
+else
+	GZIP=gzip
+fi
+
 # Save
 m "saving $IMAGE..."
-podman save "$IMAGE" --output "$WORK/image.tar"
+"$PODMAN" save "$IMAGE" --output "$WORK/image.tar"
 
 # Unpack
 m "unpacking..."
@@ -46,5 +58,5 @@ mv --force "$WORK/image/manifest.json~" "$WORK/image/manifest.json"
 # Repack
 m "repacking to $FILE..."
 pushd "$WORK/image" > /dev/null
-tar --create --use-compress-program=pigz --file="$FILE" *
+tar --create --use-compress-program="$GZIP" --file="$FILE" *
 popd > /dev/null