[CI] Add Remote Caching (#6210)

.travis.yml

@@ -116,7 +116,7 @@ matrix:
         # For the linux wheel build, we use a shared cache between all
         # wheels, but not between different travis runs, because that
         # caused timeouts in the past. See the "cache: false" line below.
-        - export MOUNT_BAZEL_CACHE="-v $HOME/ray-bazel-cache:/root/ray-bazel-cache -e TRAVIS=true"
+        - export MOUNT_BAZEL_CACHE="-v $HOME/ray-bazel-cache:/root/ray-bazel-cache -e TRAVIS=true -e TRAVIS_PULL_REQUEST=$TRAVIS_PULL_REQUEST"
 
         # This command should be kept in sync with ray/python/README-building-wheels.md,
         # except the `$MOUNT_BAZEL_CACHE` part.

ci/travis/install-bazel.sh

@@ -3,6 +3,8 @@
 # Cause the script to exit if a single command fails
 set -e
 
+ROOT_DIR=$(cd "$(dirname "${BASH_SOURCE:-$0}")"; pwd)
+
 platform="unknown"
 unamestr="$(uname)"
 if [[ "$unamestr" == "Linux" ]]; then
@@ -26,4 +28,17 @@ if [[ "$TRAVIS" == "true"  ]]; then
   # Use bazel disk cache if this script is running in Travis.
   mkdir -p $HOME/ray-bazel-cache
   echo "build --disk_cache=$HOME/ray-bazel-cache" >> $HOME/.bazelrc
+
+  # Use ray google cloud cache
+  echo "build --remote_cache=https://storage.googleapis.com/ray-bazel-cache" >> $HOME/.bazelrc
+  if [[ "$TRAVIS_PULL_REQUEST" == "false" ]]; then
+    # If we are in master build, we can write to the cache as well.
+    openssl aes-256-cbc -K $encrypted_1c30b31fe1ee_key \
+      -iv $encrypted_1c30b31fe1ee_iv \
+      -in $ROOT_DIR/bazel_cache_credential.json.enc \
+      -out $HOME/bazel_cache_credential.json -d
+    echo "build --google_credentials=$HOME/bazel_cache_credential.json" >> $HOME/.bazelrc
+  else
+    echo "build --remote_upload_local_results=false" >> $HOME/.bazelrc
+  fi
 fi