Remote build cache for Bazel

Generate a Personal Access Token on Bitrise: Creating a personal access token.

Copy the value of the token, as you will need it during the process.

Find your Workspace ID. You can do so by navigating to the Workspace's page and find the ID in the URL.

Create a file called .bitrise.bazelrc.tpl with the following content:

build --remote_cache=grpcs://pluggable.services.bitrise.io
build --remote_header=x-org-id=<workspace-slug>
build --remote_header=authorization="Bearer $BITRISE_PERSONAL_ACCESS_TOKEN"

Add the following line to your .bazelrc configuration file:

try-import %workspace%/.bitrise.bazelrc

With this configuration, .bitrise.bazelrc will be loaded if present, but won’t cause issues if it isn’t present. The bazel commands will run but without a build cache if .bitrise.bazelrc isn’t present.

Create the bitrise.bazelrc file from the bitrise.bazelrc.tpl template file:

export BITRISE_PERSONAL_ACCESS_TOKEN=your-personal-access-token
envsubst < .bitrise.bazelrc.tpl > .bitrise.bazelrc

Add the bitrise.bazelrc file to .gitignore.

This is a security measure: the file includes your personal access token so it should not be visible to the public.

Add a Script Step to your Workflow.

In the Content input, add the following:

#!/usr/bin/env bash
# fail if any commands fails
set -e
# make pipelines' return status equal the last command to exit with a non-zero status, or zero if all commands exit successfully
set -o pipefail
# debug log
set -x

# === CONFIG ===
export BAZELRC_PATH='./.bazelrc'
export BITRISE_BAZELRC_TEMPLATE_PATH='./.bitrise.ci.bazelrc.tpl'
# ==============

# Install needed tools for Bazel (only needed on Linux)
# Note: this isn't needed for Bitrise Build Cache specifically, if you install bazelisk or bazel in a different way yourself feel free to remove this section
if [ $(uname) == "Linux" ]; then
  apt-get update
  apt-get install -y gettext-base

  wget https://github.com/bazelbuild/bazelisk/releases/download/v1.17.0/bazelisk-linux-amd64
  chmod +x bazelisk-linux-amd64
  mv bazelisk-linux-amd64 /usr/local/bin/bazel
fi

# Create .bitrise.ci.bazelrc.tpl file
cat <<EOF > $BITRISE_BAZELRC_TEMPLATE_PATH
build --remote_cache=\$BITRISE_CACHE_ENDPOINT
build --remote_header=authorization="Bearer \$BITRISEIO_BITRISE_SERVICES_ACCESS_TOKEN"
build --remote_header=x-app-id=\$BITRISE_APP_SLUG
build --remote_header=x-flare-buildtool=bazel
build --remote_header=x-flare-builduser=bitrise
build --remote_header=x-flare-build-id=\$BITRISE_BUILD_SLUG
build --remote_header=x-flare-step-id=\$BITRISE_STEP_EXECUTION_ID
EOF

# Check if .bazelrc already has the necessary try-import
# If not, then add it
if ! grep -q 'try-import %workspace%/.bitrise.bazelrc' "${BAZELRC_PATH}"; then
  # Add a new-line to .bazelrc file just to be sure we're not appending to the last line
  echo '' >> "${BAZELRC_PATH}"
  # Add the .bitrise.bazelrc import in a non breaking way
  echo 'try-import %workspace%/.bitrise.bazelrc' >> "${BAZELRC_PATH}"
fi

# Setup cache endpoint
case "${BITRISE_DEN_VM_DATACENTER}" in
LAS1)
export BITRISE_CACHE_ENDPOINT=grpc://las-cache.services.bitrise.io:6666
;;
ATL1)
export BITRISE_CACHE_ENDPOINT=grpc://atl-cache.services.bitrise.io:6666
;;
*)
export BITRISE_CACHE_ENDPOINT=grpcs://pluggable.services.bitrise.io
;;
esac

envsubst < "${BITRISE_BAZELRC_TEMPLATE_PATH}" > .bitrise.bazelrc
echo "selected cache endpoint: ${BITRISE_CACHE_ENDPOINT}"

This script creates a .bitrise.bazelrc file and modifies the specified .bazelrc file to try to import it (unless the try-import is already in the .bazelrc). The .bitrise.bazelrc file has all the necessary configurations to enable Bitrise build cache for Bazel for the project, and to eliminate latency, it selects the closest cache server depending on which Bitrise data center the build is running in.