build: add back builder-run utility script

For executing & testing scripts via our build container for
consistent builds.

Author: Ed Rooth

builder-run

@@ -0,0 +1,24 @@
+#!/bin/bash -e
+#
+# A utility script for executing arbitrary local scripts via docker.
+# This can be used for executing build/release scripts locally in our build container in the absence of Jenkins.
+#
+# USAGE:
+#
+# With env vars:
+#   MYVAR=foo OTHERVAR=bar DOCKER_ENV=MYVAR,OTHERVAR ./builder-run ./my-script --my-script-arg1 --my-script-arg2
+#
+# Without env vars:
+#   ./builder-run ./my-script --my-script-arg1 --my-script-arg2
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+# forward whitelisted env variables to docker
+ENV_STR=""
+for VAR in ${DOCKER_ENV//,/ }; do
+    ENV_STR="$ENV_STR -e $VAR=${!VAR}"
+done
+
+PROJECT=$SCRIPT_DIR
+set -x
+docker run --user="${BUILDER_RUN_USER}" $ENV_STR --rm -v $PROJECT:/go/src/github.com/coreos/tectonic-installer -w /go/src/coreos/tectonic-installer $DOCKER_RUN_ARGS $BUILDER_IMAGE $@