From 9cc29a013a0a232002e80981bd66c7189d12dddf Mon Sep 17 00:00:00 2001
From: "W. Trevor King" <wking@tremily.us>
Date: Mon, 21 Jul 2014 17:53:46 -0700
Subject: [PATCH] trim.sh: Work-in-progress container reduction script

Dump everything except @world and it's runtime dependencies (and dump
the Docker history too) to get a container down to a reasonable size.
---
 trim.sh | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100755 trim.sh

diff --git a/trim.sh b/trim.sh
new file mode 100755
index 0000000..1091a69
--- /dev/null
+++ b/trim.sh
@@ -0,0 +1,71 @@
+#!/bin/sh
+#
+# Copyright (C) 2013-2014 W. Trevor King <wking@tremily.us>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# * Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+die()
+{
+	echo "$1"
+	exit 1
+}
+
+trim()
+{
+	IMAGE="$1"
+	NAMESPACE_REPOSITORY="${IMAGE%:*}"
+	TAG="${IMAGE#*:}"
+	if [ "${TAG}" = "${NAMESPACE_REPOSITORY}" ]
+	then
+		TAG=""
+	fi
+	REPOSITORY="${NAMESPACE_REPOSITORY#*/}"
+	CONTAINER="${REPOSITORY}-trimmed-container"
+	IMG="${NAMESPACE_REPOSITORY}-trimmed"
+	if [ -n "${TAG}" ]
+	then
+		IMG="${IMG}:${TAG}"
+	fi
+	#sys-apps/openrc     (/sbin/rc)
+	#sys-apps/net-tools  (/bin/hostname)
+	#sys-devel/gettext   (/usr/bin/envsubst)
+	# unmerge GCC to break the GCC <-> libc dependency loop
+	docker run -t --name "${CONTAINER}" \
+		-v "${PWD}/empty-system.py:/tmp/empty-system.py" \
+		"${IMAGE}" /bin/bash -c "
+			/tmp/empty-system.py &&
+			emerge --noreplace app-shells/bash sys-apps/net-tools sys-apps/openrc sys-devel/gettext &&
+			emerge --unmerge sys-devel/gcc &&
+			emerge -v --depclean &&
+			rm -rf /usr/portage" ||
+		die "failed to create ${CONTAINER}"
+	docker export "${CONTAINER}" | docker import - "${IMG}" ||
+		die "failed to export/import ${IMG}"
+	docker rm "${CONTAINER}" ||
+		die "failed to remove ${CONTAINER}"
+}
+
+for IMAGE in "$@"
+do
+	trim "${IMAGE}"
+done
-- 
2.26.2