From 534c627c28d651baedcb14b65ed60fc2c227677c Mon Sep 17 00:00:00 2001
From: Damon Kohler <damonkohler@gmail.com>
Date: Tue, 18 Oct 2016 15:42:23 +0200
Subject: [PATCH] Adds Docker caching to Travis. (#72)

---
 .travis.yml                  | 15 ++++++++++++++-
 Dockerfile                   |  4 +++-
 scripts/load_docker_cache.sh | 25 +++++++++++++++++++++++++
 scripts/save_docker_cache.sh | 28 ++++++++++++++++++++++++++++
 4 files changed, 70 insertions(+), 2 deletions(-)
 create mode 100755 scripts/load_docker_cache.sh
 create mode 100755 scripts/save_docker_cache.sh

diff --git a/.travis.yml b/.travis.yml
index 01d4b31..0477c90 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,5 +14,18 @@
 
 sudo: required
 services: docker
+
+# Cache intermediate Docker layers. For a description of how this works, see:
+# https://giorgos.sealabs.net/docker-cache-on-travis-and-docker-112.html
+cache:
+  directories:
+    - /home/travis/docker/
+env:
+  global:
+    - DOCKER_CACHE_FILE=/home/travis/docker/cache.tar.gz
+before_install: scripts/load_docker_cache.sh
+
 install: true
-script: docker build ${TRAVIS_BUILD_DIR} -t cartographer
+script:
+  - docker build ${TRAVIS_BUILD_DIR} -t cartographer
+  - scripts/save_docker_cache.sh
diff --git a/Dockerfile b/Dockerfile
index b5024c0..9180fd5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,7 +13,9 @@
 # limitations under the License.
 
 FROM ubuntu:trusty
-COPY . cartographer
+COPY scripts/install_debs.sh cartographer/scripts/
 RUN cartographer/scripts/install_debs.sh && rm -rf /var/lib/apt/lists/*
+COPY scripts/install_ceres.sh cartographer/scripts/
 RUN cartographer/scripts/install_ceres.sh && rm -rf ceres-solver
+COPY . cartographer
 RUN cartographer/scripts/install_cartographer.sh && rm -rf cartographer
diff --git a/scripts/load_docker_cache.sh b/scripts/load_docker_cache.sh
new file mode 100755
index 0000000..c4f218d
--- /dev/null
+++ b/scripts/load_docker_cache.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# Copyright 2016 The Cartographer Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Cache intermediate Docker layers. For a description of how this works, see:
+# https://giorgos.sealabs.net/docker-cache-on-travis-and-docker-112.html
+
+set -o errexit
+set -o verbose
+
+if [ -f ${DOCKER_CACHE_FILE} ]; then
+  gunzip -c ${DOCKER_CACHE_FILE} | docker load;
+fi
diff --git a/scripts/save_docker_cache.sh b/scripts/save_docker_cache.sh
new file mode 100755
index 0000000..d83061b
--- /dev/null
+++ b/scripts/save_docker_cache.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# Copyright 2016 The Cartographer Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Cache intermediate Docker layers. For a description of how this works, see:
+# https://giorgos.sealabs.net/docker-cache-on-travis-and-docker-112.html
+
+set -o errexit
+set -o verbose
+
+if [[ ${TRAVIS_BRANCH} == "master" ]] &&
+    [[ ${TRAVIS_PULL_REQUEST} == "false" ]]; then
+  mkdir -p $(dirname ${DOCKER_CACHE_FILE});
+  docker save $(docker history -q ${DOCKER_REPOSITORY}:${TRAVIS_COMMIT} |
+      grep -v '<missing>') | gzip > ${DOCKER_CACHE_FILE};
+fi