devcontainer-cache-build-initialize

#!/bin/bash

set -e


###### Handle repeated call to devcontainer up ######

if [[ -z ${DEVCONTAINER_INITIALIZE_PID+x} ]]; then
  echo "DEVCONTAINER_INITIALIZE_PID undefined; will not check for --expect-existing-container, instead will assume that a build is required."
else
  set +e
  # Get the PID of the process that called initialize
  INITIALIZE_CALLER_PID="$(ps -o ppid= ${DEVCONTAINER_INITIALIZE_PID})"
  # Strip whitespace from the PID value
  INITIALIZE_CALLER_PID=${INITIALIZE_CALLER_PID// /}
  cat /proc/${INITIALIZE_CALLER_PID}/cmdline | grep -q "expect-existing-container"
  EXPECT_EXISTING_CONTAINER=$?
  set -e
  if [[ $EXPECT_EXISTING_CONTAINER == 0 ]]; then
    echo "devcontainer up command includes --expect-existing-container, indicating that it is a repeat call after the intial build. Exiting, as no build is required in this case."
    exit 0
  fi
fi


###### Inputs with simple defaults ######

DEVCONTAINER_CONTEXT="${DEVCONTAINER_CONTEXT:=.}"
DEVCONTAINER_DEFINITION_TYPE="${DEVCONTAINER_DEFINITION_TYPE:=build}"
DEVCONTAINER_PUSH_IMAGE="${DEVCONTAINER_PUSH_IMAGE:=false}"
DEVCONTAINER_DEFAULT_BRANCH_NAME="${DEVCONTAINER_DEFAULT_BRANCH_NAME:=main}"

# Replace any non-alphanumeric (or underscore) characters in the branch names with dashes
GIT_BRANCH="$(git rev-parse --abbrev-ref HEAD)"
GIT_BRANCH_SANITIZED="${GIT_BRANCH//[^a-zA-Z0-9_]/-}"
DEVCONTAINER_DEFAULT_BRANCH_NAME_SANITIZED="${DEVCONTAINER_DEFAULT_BRANCH_NAME//[^a-zA-Z0-9_]/-}"


###### Inputs with computed defaults ######

DEVCONTAINER_DEFINITION_FILES="${DEVCONTAINER_DEFINITION_FILES:=.devcontainer/Dockerfile}"


# Compute outputs
DEFAULT_DEVCONTAINER_OUTPUTS=" \
  type=docker,name=${DEVCONTAINER_IMAGE}
"

if [[ "${DEVCONTAINER_REGISTRY}" != "" ]]; then
  DEVCONTAINER_IMAGE_REF="${DEVCONTAINER_REGISTRY}/${DEVCONTAINER_IMAGE}"
else
  DEVCONTAINER_IMAGE_REF="$DEVCONTAINER_IMAGE"
fi

# If the build will push, add an image type output arg
if [[ "$DEVCONTAINER_PUSH_IMAGE" == true ]]; then
  DEFAULT_DEVCONTAINER_OUTPUTS=" \
    $DEFAULT_DEVCONTAINER_OUTPUTS \
    type=image,name=${DEVCONTAINER_IMAGE_REF}:${GIT_BRANCH_SANITIZED},push=${DEVCONTAINER_PUSH_IMAGE} \
  "
fi
DEVCONTAINER_OUTPUTS=${DEVCONTAINER_OUTPUTS:=${DEFAULT_DEVCONTAINER_OUTPUTS}}

# By default, pull cache:
# - From the ref populated by CI for this branch
# - From the ref populated by local runs for this branch
# - From the ref populated by CI for the main branch
DEFAULT_DEVCONTAINER_CACHE_FROMS=" \
  type=registry,ref=${DEVCONTAINER_IMAGE_REF}-cache:${GIT_BRANCH_SANITIZED} \
  type=registry,ref=${DEVCONTAINER_IMAGE_REF}-cache:local-${GIT_BRANCH_SANITIZED} \
  type=registry,ref=${DEVCONTAINER_IMAGE_REF}-cache:${DEVCONTAINER_DEFAULT_BRANCH_NAME_SANITIZED} \
"
DEVCONTAINER_CACHE_FROMS="${DEVCONTAINER_CACHE_FROMS:=${DEFAULT_DEVCONTAINER_CACHE_FROMS}}"

if [[ "${CI}" != "true" ]]; then
  DEFAULT_DEVCONTAINER_CACHE_TOS=" \
    type=registry,rewrite-timestamp=true,mode=max,ref=${DEVCONTAINER_IMAGE_REF}-cache:local-${GIT_BRANCH_SANITIZED} \
  "
else
  DEFAULT_DEVCONTAINER_CACHE_TOS=" \
    type=registry,rewrite-timestamp=true,mode=max,ref=${DEVCONTAINER_IMAGE_REF}-cache:${GIT_BRANCH_SANITIZED} \
  "
fi
DEVCONTAINER_CACHE_TOS="${DEVCONTAINER_CACHE_TOS:=${DEFAULT_DEVCONTAINER_CACHE_TOS}}"


###### Handle _NONE_ values ######

declare -a none_vars_names=(
  "DEVCONTAINER_DEFINITION_FILES"
  "DEVCONTAINER_OUTPUTS"
  "DEVCONTAINER_CACHE_FROMS"
  "DEVCONTAINER_CACHE_TOS"
  "DEVCONTAINER_CONTEXT"
)

for none_var_name in "${none_vars_names[@]}"
do
  if [[ "${!none_var_name}" == "_NONE_" ]]; then
    echo "${none_var_name} set to \"_NONE_\"; removing value"
    declare "${none_var_name}"=""
  fi
done


###### Strip whitespace ######

whitespace_strip_array=($DEVCONTAINER_OUTPUTS)
DEVCONTAINER_OUTPUTS="${whitespace_strip_array[@]}"
whitespace_strip_array=($DEVCONTAINER_CACHE_FROMS)
DEVCONTAINER_CACHE_FROMS="${whitespace_strip_array[@]}"
whitespace_strip_array=($DEVCONTAINER_CACHE_TOS)
DEVCONTAINER_CACHE_TOS="${whitespace_strip_array[@]}"
whitespace_strip_array=($DEVCONTAINER_DEFINITION_FILES)
DEVCONTAINER_DEFINITION_FILES="${whitespace_strip_array[@]}"


###### Execute build ######

PREVIOUS_BUILDER_NAME=$(docker builder inspect | grep Name | head -1 | awk -F " " '{print $NF}')
export SOURCE_DATE_EPOCH=1731797200 # Specify a static value for image and layer timestamps

# Set up docker-container builder
docker builder rm initialize-builder || true
docker builder create \
  --bootstrap \
  --use \
  --name initialize-builder \
  --driver docker-container

if [[ "${DEVCONTAINER_DEFINITION_TYPE}" == "build" ]]; then
  # Image build case

  # Expand image build args
  DEVCONTAINER_OUTPUT_ARG=""
  if [[ ${DEVCONTAINER_OUTPUTS} != "" ]]; then
    DEVCONTAINER_OUTPUTS=($DEVCONTAINER_OUTPUTS)
    for output in "${DEVCONTAINER_OUTPUTS[@]}"
    do
      DEVCONTAINER_OUTPUT_ARG="--output=${output} ${DEVCONTAINER_OUTPUT_ARG}"
    done
  fi
  DEVCONTAINER_CACHE_FROM_ARG=""
  if [[ ${DEVCONTAINER_CACHE_FROMS} != "" ]]; then
    DEVCONTAINER_CACHE_FROMS=($DEVCONTAINER_CACHE_FROMS)
    for cache_from in "${DEVCONTAINER_CACHE_FROMS[@]}"
    do
      DEVCONTAINER_CACHE_FROM_ARG="--cache-from= ${cache_from} ${DEVCONTAINER_CACHE_FROM_ARG}"
    done
  fi
  DEVCONTAINER_CACHE_TO_ARG=""
  if [[ ${DEVCONTAINER_CACHE_TOS} != "" ]]; then
    DEVCONTAINER_CACHE_TOS=($DEVCONTAINER_CACHE_TOS)
    for cache_to in "${DEVCONTAINER_CACHE_TOS[@]}"
    do
      DEVCONTAINER_CACHE_TO_ARG="--cache-to=${cache_to} ${DEVCONTAINER_CACHE_TO_ARG}"
    done
  fi

  # Build image
  echo "Will build image from Dockerfile \"$DEVCONTAINER_DEFINITION_FILES\" in context \"$DEVCONTAINER_CONTEXT\", with output args \"$DEVCONTAINER_OUTPUT_ARG\" and cache args \"$DEVCONTAINER_CACHE_FROM_ARG $DEVCONTAINER_CACHE_TO_ARG\""
  docker buildx build \
    --builder initialize-builder \
    --file $DEVCONTAINER_DEFINITION_FILES \
    $DEVCONTAINER_OUTPUT_ARG \
    $DEVCONTAINER_CACHE_FROM_ARG \
    $DEVCONTAINER_CACHE_TO_ARG \
    $DEVCONTAINER_CONTEXT \
    $DEVCONTAINER_BUILD_ADDITIONAL_ARGS

elif [[ "${DEVCONTAINER_DEFINITION_TYPE}" == "bake" ]]; then
  # Bake case

  # Expand multiple --file args
  DEVCONTAINER_DEFINITION_FILES_ARG=""
  if [[ ${DEVCONTAINER_DEFINITION_FILES} != "" ]]; then
    DEVCONTAINER_DEFINITION_FILES=($DEVCONTAINER_DEFINITION_FILES)
    for file in "${DEVCONTAINER_DEFINITION_FILES[@]}"
    do
      DEVCONTAINER_DEFINITION_FILES_ARG="${DEVCONTAINER_DEFINITION_FILES_ARG} --file ${file}"
    done
  fi

  # Export image config vars
  export DEVCONTAINER_OUTPUTS
  export DEVCONTAINER_CACHE_FROMS
  export DEVCONTAINER_CACHE_TOS

  # Bake image
  echo "Will bake with config:"
  docker buildx bake \
    --print \
    --builder initialize-builder \
    $DEVCONTAINER_DEFINITION_FILES_ARG \
    $DEVCONTAINER_BUILD_ADDITIONAL_ARGS

  docker buildx bake \
    --builder initialize-builder \
    $DEVCONTAINER_DEFINITION_FILES_ARG \
    $DEVCONTAINER_BUILD_ADDITIONAL_ARGS
fi

docker builder use $PREVIOUS_BUILDER_NAME