bazel: add container builder script

Signed-off-by: Paul Meyer <49727155+katexochen@users.noreply.github.com>

bazel/container/README.md

@@ -0,0 +1,23 @@
+# Bazel build container
+
+This container enables running Bazel inside a container, with the host cache mounted.
+
+To use the container, run
+
+```shell
+source container.sh
+startBazelServer
+```
+
+You can then execute Bazel commands like you normally would do, as the sourced `bazel`
+function shadows binaries you might have in your path:
+
+```shell
+bazel query //...
+```
+
+To terminate the container, which is running as daemon in the background, execute
+
+```shell
+stopBazelServer
+```

bazel/container/container.sh

@@ -0,0 +1,71 @@
+#!/usr/bin/env bash
+
+function setup {
+  # Ensure that the cache directories exist, so they are not created by docker with root permissions.
+  mkdir -p "${HOME}/.cache/bazel"
+  mkdir -p "${HOME}/.cache/shared_bazel_repository_cache"
+  mkdir -p "${HOME}/.cache/shared_bazel_action_cache"
+}
+
+function startBazelServer {
+  local containerImage="ghcr.io/edgelesssys/bazel-container:v6.1.0-0"
+  local containerName="bazeld"
+
+  setup
+
+  local hostWorkspaceDir
+  hostWorkspaceDir="$(git rev-parse --show-toplevel)"
+  if [[ $? -ne 0 ]]; then
+    echo Could not find git repository root. Are you in a git repository?
+    return 1
+  fi
+
+  echo Starting bazel container as daemon...
+  echo You can stop this command using:
+  echo docker kill "${containerName}"
+
+  docker run \
+    --rm \
+    --detach \
+    --name "${containerName}" \
+    -v "${hostWorkspaceDir}":/workspace \
+    -v "${HOME}/.cache/bazel":"/home/builder/.cache/bazel" \
+    -v "${HOME}/.cache/shared_bazel_repository_cache":"/home/builder/.cache/shared_bazel_repository_cache" \
+    -v "${HOME}/.cache/shared_bazel_action_cache":"/home/builder/.cache/shared_bazel_action_cache" \
+    --entrypoint=/bin/sleep \
+    "${containerImage}" \
+    infinity || return $?
+}
+
+function stopBazelServer {
+  local containerName="bazeld"
+
+  echo Stopping bazel container...
+
+  docker kill "${containerName}" || return $?
+}
+
+function bazel {
+  local containerName="bazeld"
+
+  local hostWorkspaceDir
+  hostWorkspaceDir="$(git rev-parse --show-toplevel)"
+  if [[ $? -ne 0 ]]; then
+    echo Could not find git repository root. Are you in a git repository?
+    return 1
+  fi
+
+  local containerWorkDir
+  containerWorkDir=$(realpath -m "/workspace/$(realpath --relative-base="${hostWorkspaceDir}" .)")
+  if [[ $? -ne 0 ]]; then
+    echo Could not determine container work directory.
+    return 1
+  fi
+
+  docker exec \
+    -it \
+    --workdir "${containerWorkDir}" \
+    --env "HOST_CACHE=${HOME}/.cache" \
+    "${containerName}" \
+    bazel "$@" || return $?
+}