Interactive Builds: git-watch, cool-bazel, ibazel

README.md

Some little scripts I've found useful for development. git-watch retriggers a command when your git repo changes, so can give interactive rebuilds like ibazel except I found that https://github.com/bazelbuild/bazel-watcher didn't work for me at all. This is also completely agnostic to the command, so can be used with CMake as well, for instance.

cool-bazel

#!/bin/bash

# Copyright 2021 Google LLC.
# SPDX-License-Identifier: Apache-2.0

# https://c.tenor.com/w6fXtUDvwoYAAAAC/can-you-just-be-cool-just-once.gif

set -euo pipefail

COOL_BAZEL_RC_FILE="$(mktemp --tmpdir cool-bazel.XXXXX.bazelrc)"

function cleanup() {
  rm "${COOL_BAZEL_RC_FILE}"
}
trap cleanup EXIT

COPTS=(
  "-Wno-unused"
)
COPTS_STRING="$(IFS="," ; echo "${COPTS[*]}")"

readarray -t EDITED < <(git diff --name-only --diff-filter=AM --ignore-submodules | grep -i '.*\.h$\|.*\.c$\|.*\.cc$\|.*\.cpp$' | sed 's/\./\\\./g')

# Prefix with `^` anchor
EDITED=( "${EDITED[@]/#/^}" )
# Suffix with `$` anchor
EDITED=( "${EDITED[@]/%/$}" )
# Join on `,`
EDITED_STRING="$(IFS="," ; echo "${EDITED[*]}")"

if (( "${#EDITED[@]}" )); then
  echo "build --per_file_copt=${EDITED_STRING}@${COPTS_STRING}" > "${COOL_BAZEL_RC_FILE}"
fi

bazel --bazelrc="${COOL_BAZEL_RC_FILE}"  "$@"

cool-bazel-bash-completion

# -*- sh -*-

# Copyright 2021 Google LLC.
# SPDX-License-Identifier: Apache-2.0

# Just copy Bazel autocompletion

complete -F _bazel__complete -o nospace cool-bazel
complete -F _bazel__complete -o nospace ibazel

git-watch

#!/bin/bash

# Copyright 2021 Google LLC.
# SPDX-License-Identifier: Apache-2.0

set -u

WATCHED_COMMAND=$1
shift
declare -a WATCHED_ARGS=("$@")

function check_exists() {
  if ! type "$1" > /dev/null 2>&1; then
    echo "$1 command not found. Is it installed?"
    exit 1
  fi
}

check_exists git
check_exists inotifywait

GIT_ROOT="$(git rev-parse --show-toplevel)"

if (( "$?" != 0 )); then
  echo "Failed to find git root. Are you in a git directory?"
  exit 1
fi

function watched_command() {
  (set -x; ${WATCHED_COMMAND} "${WATCHED_ARGS[@]}")
  echo "...completed with exit code $?"
}

echo "Running initial command before establishing watches."
watched_command &
PID="$!"

declare -a inotify_command=(
  inotifywait
  # inotifywait will output info about setting up watches, but we don't actually
  # wait for it to finish set up before running our first command. I couldn't
  # find a good way to do so and the command we run may stomp on the
  # "Watches established" message, so we avoid outputtting the message at all.
  --quiet
  --event=modify,move,create,delete,attrib
  --monitor
  --recursive
  # Output the full filepath, watched directory + filename 
  --format="%w%f"
  # Watch everything under the git root
  "${GIT_ROOT?}"
  # Except the .git directory (this is not gitignored)
  "@${GIT_ROOT?}/.git"
)

while read -r filepath; do
  if ! git check-ignore -q "${filepath?}"; then
    kill "${PID?}" > /dev/null 2>&1
    # Wait for the process to actually exit.
    # Technically this can hang forever if the process doesn't respond properly
    # to SIGTERM. Hopefully the user will just Ctrl+C at that point. Suggestions
    # for how to add a deadline to this welcome. `timeout wait` doesn't work
    # since wait is a shell builtin.
    wait "${PID?}"
    printf "\n\nWatched file ${filepath} changed. Restarting\n\n"
    watched_command &
    PID="$!"
  fi
done < <("${inotify_command[@]}")

ibazel

#!/bin/bash

# Copyright 2021 Google LLC.
# SPDX-License-Identifier: Apache-2.0

# *Not* $@ which results in commands ending up like
# `bash -c 'cool-bazel test' //target/...`
# and building nothing
git watch "cool-bazel $*"