From 37c75aac41396d6eab5b62680c75ba8e8dbb0b6b Mon Sep 17 00:00:00 2001
From: Philip Hyunsu Cho <chohyu01@cs.washington.edu>
Date: Thu, 4 Apr 2019 13:36:39 -0700
Subject: [PATCH] [CI] Add external Docker build cache (#4331)

---
 Jenkinsfile                |  4 ++++
 tests/ci_build/ci_build.sh | 34 +++++++++++++++++++++++++++++++---
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/Jenkinsfile b/Jenkinsfile
index 04a918cfc..96268901e 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -24,6 +24,10 @@ pipeline {
     // Each stage specify its own agent
     agent none
 
+    environment {
+        DOCKER_CACHE_REPO = '492475357299.dkr.ecr.us-west-2.amazonaws.com'
+    }
+
     // Setup common job properties
     options {
         ansiColor('xterm')
diff --git a/tests/ci_build/ci_build.sh b/tests/ci_build/ci_build.sh
index 942be875e..d5b0419f9 100755
--- a/tests/ci_build/ci_build.sh
+++ b/tests/ci_build/ci_build.sh
@@ -118,15 +118,30 @@ EOF
 
 # Build the docker container.
 echo "Building container (${DOCKER_IMG_NAME})..."
-# --pull should be default
+
+# If enviornment variable DOCKER_CACHE_REPO is set, use an external Docker repo for build caching
+if [[ -n "${DOCKER_CACHE_REPO}" ]]
+then
+    # Login for Docker registiry
+    echo '$(python3 -m awscli ecr get-login --no-include-email --region us-west-2)'
+    $(python3 -m awscli ecr get-login --no-include-email --region us-west-2)
+    echo "docker pull ${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME} || true"
+    docker pull "${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME}" || true
+    CACHE_FROM_CMD="--cache-from ${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME}"
+else
+    CACHE_FROM_CMD=''
+fi
+
 echo "docker build \
     ${CI_DOCKER_BUILD_ARG} \
     -t ${DOCKER_IMG_NAME} \
-    -f ${DOCKERFILE_PATH} ${DOCKER_CONTEXT_PATH}"
+    -f ${DOCKERFILE_PATH} ${DOCKER_CONTEXT_PATH} \
+    ${CACHE_FROM_CMD}"
 docker build \
     ${CI_DOCKER_BUILD_ARG} \
     -t "${DOCKER_IMG_NAME}" \
-    -f "${DOCKERFILE_PATH}" "${DOCKER_CONTEXT_PATH}"
+    -f "${DOCKERFILE_PATH}" "${DOCKER_CONTEXT_PATH}" \
+    ${CACHE_FROM_CMD}
 
 # Check docker build status
 if [[ $? != "0" ]]; then
@@ -134,6 +149,19 @@ if [[ $? != "0" ]]; then
     exit 1
 fi
 
+# If enviornment variable DOCKER_CACHE_REPO is set, use an external Docker repo for build caching
+if [[ -n "${DOCKER_CACHE_REPO}" ]]
+then
+    echo "docker tag ${DOCKER_IMG_NAME} ${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME}"
+    docker tag "${DOCKER_IMG_NAME}" "${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME}"
+    echo "docker push ${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME}"
+    docker push "${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME}"
+    if [[ $? != "0" ]]; then
+        echo "ERROR: could not update Docker cache ${DOCKER_CACHE_REPO}/${DOCKER_IMG_NAME}:${BRANCH_NAME}"
+        exit 1
+    fi
+fi
+
 
 # Run the command inside the container.
 echo "Running '${COMMAND[*]}' inside ${DOCKER_IMG_NAME}..."