get_ci_vm : allow running without sudo

More complicated than one would think. The first problem is that,
on certain (but not all) Fedora systems, podman cannot mount
volumes read-only (issue #2312). This is baffling, and since
it's not easily reproducible it's likely that the dev team
will not spend much effort on it. Workaround: instead of bind-
mounting /tmp read-only, bind-mount a *tempdir* (subdirectory)
read-write. This is actually cleaner in some ways but it
leads to complications with the paths we use and with cleanup.

Next, allow overriding the default image and allow asking
for no sudo:

    export GCLOUD_IMAGE=quay.io/edsantiago/gcloud_centos:latest
    export GCLOUD_SUDO=

(yes, that's an equal-sign and EOL. Just an empty string).

The third part, unfortunately, requires a custom image because
the as_dollar_user.sh script (the one that runs gcloud in a
container) is hardwired in a cevich image and needs tweaks
in order to detect rootless and avoid sudo.

Signed-off-by: Ed Santiago <santiago@redhat.com>

hack/get_ci_vm.sh

@@ -17,8 +17,14 @@ MEMORY="4Gb"
 DISK="200"
 PROJECT="libpod-218412"
 GOSRC="/var/tmp/go/src/github.com/containers/libpod"
+GCLOUD_IMAGE=${GCLOUD_IMAGE:-quay.io/cevich/gcloud_centos:latest}
+GCLOUD_SUDO=${GCLOUD_SUDO-sudo}
+
+# Shared tmp directory between container and us
+TMPDIR=$(mktemp -d --tmpdir $(basename $0)_tmpdir_XXXXXX)
+
 # Command shortcuts save some typing
-PGCLOUD="sudo podman run -it --rm -e AS_ID=$UID -e AS_USER=$USER --security-opt label=disable -v /home/$USER:$HOME -v /tmp:/tmp:ro quay.io/cevich/gcloud_centos:latest --configuration=libpod --project=$PROJECT"
+PGCLOUD="$GCLOUD_SUDO podman run -it --rm -e AS_ID=$UID -e AS_USER=$USER --security-opt label=disable -v /home/$USER:$HOME -v $TMPDIR:/tmp $GCLOUD_IMAGE --configuration=libpod --project=$PROJECT"
 SCP_CMD="$PGCLOUD compute scp"
 
 LIBPODROOT=$(realpath "$(dirname $0)/../")
@@ -39,19 +45,20 @@ showrun() {
     fi
 }
 
-TEMPFILE=$(mktemp -p '' $(basename $0)_XXXXX.tar.bz2)
 cleanup() {
     set +e
     wait
-    rm -f "$TEMPFILE"
+
+    # set GCLOUD_DEBUG to leave tmpdir behind for postmortem
+    test -z "$GCLOUD_DEBUG" && rm -rf $TMPDIR
 }
 trap cleanup EXIT
 
 delvm() {
-    cleanup
     echo -e "\n"
     echo -e "\n${YEL}Offering to Delete $VMNAME ${RED}(Might take a minute or two)${NOR}"
     showrun $CLEANUP_CMD  # prompts for Yes/No
+    cleanup
 }
 
 image_hints() {
@@ -128,16 +135,16 @@ parse_args $@
 cd $LIBPODROOT
 
 # Attempt to determine if named 'libpod' gcloud configuration exists
-showrun $PGCLOUD info > $TEMPFILE
-if egrep -q "Account:.*None" "$TEMPFILE"
+showrun $PGCLOUD info > $TMPDIR/gcloud-info
+if egrep -q "Account:.*None" $TMPDIR/gcloud-info
 then
     echo -e "\n${YEL}WARNING: Can't find gcloud configuration for libpod, running init.${NOR}"
     echo -e "         ${RED}Please choose "#1: Re-initialize" and "login" if asked.${NOR}"
     showrun $PGCLOUD init --project=$PROJECT --console-only --skip-diagnostics
 
     # Verify it worked (account name == someone@example.com)
-    $PGCLOUD info > $TEMPFILE
-    if egrep -q "Account:.*None" "$TEMPFILE"
+    $PGCLOUD info > $TMPDIR/gcloud-info-after-init
+    if egrep -q "Account:.*None" $TMPDIR/gcloud-info-after-init
     then
         echo -e "${RED}ERROR: Could not initialize libpod configuration in gcloud.${NOR}"
         exit 5
@@ -150,8 +157,10 @@ then
 fi
 
 # Couldn't make rsync work with gcloud's ssh wrapper :(
+TARBALL_BASENAME=$VMNAME.tar.bz2
+TARBALL=/tmp/$TARBALL_BASENAME
 echo -e "\n${YEL}Packing up repository into a tarball $VMNAME.${NOR}"
-showrun --background tar cjf $TEMPFILE --warning=no-file-changed -C $LIBPODROOT .
+showrun --background tar cjf $TMPDIR/$TARBALL_BASENAME --warning=no-file-changed -C $LIBPODROOT .
 
 trap delvm INT  # Allow deleting VM if CTRL-C during create
 # This fails if VM already exists: permit this usage to re-init
@@ -186,13 +195,13 @@ showrun $SSH_CMD --command "mkdir -p $GOSRC"
 
 echo -e "\n${YEL}Transfering tarball to $VMNAME.${NOR}"
 wait
-showrun $SCP_CMD $TEMPFILE root@$VMNAME:$TEMPFILE
+showrun $SCP_CMD $TARBALL root@$VMNAME:$TARBALL
 
 echo -e "\n${YEL}Unpacking tarball into $GOSRC on $VMNAME.${NOR}"
-showrun $SSH_CMD --command "tar xjf $TEMPFILE -C $GOSRC"
+showrun $SSH_CMD --command "tar xjf $TARBALL -C $GOSRC"
 
 echo -e "\n${YEL}Removing tarball on $VMNAME.${NOR}"
-showrun $SSH_CMD --command "rm -f $TEMPFILE"
+showrun $SSH_CMD --command "rm -f $TARBALL"
 
 echo -e "\n${YEL}Executing environment setup${NOR}"
 [[ "$1" == "-p" ]] && echo -e "${RED}Using package-based dependencies.${NOR}"