Add a kola verb

This is the first place we're wrapping mantle via our
main entrypoint, and hopefully we'll increase that.

Example usage: `coreos-assembler kola run rhcos.basic`.

Requires: coreos/mantle#920

src/cmd-kola

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+dn=$(dirname $0)
+. ${dn}/cmdlib.sh
+
+latest_qcow=$(get_latest_qemu)
+if [ -z "${latest_qcow}" ]; then
+    fatal "No latest build"
+fi
+
+# XXX: teach to kola to auto-detect based on prefix; see discussions in
+# https://github.com/coreos/coreos-assembler/pull/85
+distro=
+bn=$(basename "${latest_qcow}")
+if [[ ${bn} = fedora-coreos-* ]]; then
+    distro="-b fcos"
+elif [[ ${bn} = rhcos-* ]]; then
+    distro="-b rhcos --ignition-version v2"
+else
+    echo "WARNING: Failed to detect distro, use -b to specify"
+fi
+
+# let's print out the actual exec() call we do
+set -x
+
+# shellcheck disable=SC2086
+exec kola $distro --output-dir tmp/kola --qemu-image "${latest_qcow}" "$@"

src/cmd-run

@@ -78,10 +78,8 @@ done
 preflight
 
 if [ -z "${VM_DISK}" ]; then
-    if [ -L ./builds/latest ]; then
-        latest_build=$(readlink builds/latest)
-        VM_DISK=$(ls builds/"${latest_build}"/*-"${latest_build}"-qemu.qcow2)
-    else
+    VM_DISK=$(get_latest_qemu)
+    if [ -z "${VM_DISK}" ]; then
         die "No builds/latest, and no -d argument provided"
     fi
 fi

src/cmdlib.sh

@@ -515,3 +515,18 @@ run_virtinstall() {
                                            --ostree-repo="${ostree_repo}" "$@"
     mv "${tmpdest}" "${dest}"
 }
+
+get_latest_build() {
+    if [ -L builds/latest ]; then
+        readlink builds/latest
+    fi
+}
+
+get_latest_qemu() {
+    local latest
+    latest=$(get_latest_build)
+    if [ -n "$latest" ]; then
+        # shellcheck disable=SC2086
+        ls builds/${latest}/*-qemu.qcow2
+    fi
+}

src/coreos-assembler

@@ -39,7 +39,7 @@ build_commands="init fetch build run prune clean"
 # commands more likely to be used in a prod pipeline only
 advanced_build_commands="buildprep oscontainer"
 buildextend_commands="aws gcp openstack installer vmware metal"
-utility_commands="tag compress bump-timestamp koji-upload"
+utility_commands="tag compress bump-timestamp koji-upload kola"
 other_commands="shell"
 if [ -z "${cmd}" ]; then
     echo Usage: "coreos-assembler CMD ..."