dblab engine snapshot preprocessing example

preprocessing.sh

#!/bin/bash
# preprocessing.sh

POSTGRES_VERSION=14
POSTGRES_IMAGE="postgresai/extended-postgres:${POSTGRES_VERSION}"

POOL_NAME=dblab_pool
MOUNT_DIR=/var/lib/dblab/"${POOL_NAME}"

# logical mode (with dataset)
CURRENT_DATASET=$(find "${MOUNT_DIR}" -name data -type d -exec stat -c "%Y %n" {} \; | sort -n -r | head -1 | awk -F "/" '{print $6}')
CLONE_PRE_PATH=$(zfs list -t filesystem | grep "${POOL_NAME}" | grep "${CURRENT_DATASET}" | head -1 | awk '{print $5}')
# physical mode
#CLONE_PRE_PATH=$(zfs list -S dblab:datastateat -t filesystem | grep "${POOL_NAME}" | grep clone_pre | tail -1 | awk '{print $5}')
CLONE_PRE="${CLONE_PRE_PATH##*/}"

# psql command
_PSQL="docker exec dblab_preprocess_${CLONE_PRE} psql -U postgres"

# functions
function info() {
  echo -e "$(date '+%Y/%m/%d %H:%M:%S') preprocessing.sh: [INFO] ${1}"
}

function error() {
  echo -e "$(date '+%Y/%m/%d %H:%M:%S') preprocessing.sh: [ERROR] ${1}" >&2
  exit 1
}

# run Docker container dblab_preprocess
docker rm -f dblab_preprocess_"${CLONE_PRE}" >/dev/null 2>&1
info "Running container: dblab_preprocess_${CLONE_PRE}"
if ! docker run -d --rm --name dblab_preprocess_"${CLONE_PRE}" \
  --label dblab_control \
  --volume /var/run/docker.sock:/var/run/docker.sock \
  --volume "${CLONE_PRE_PATH}":/var/lib/dblab:rshared \
  --env PGDATA=/var/lib/dblab/data \
  "${POSTGRES_IMAGE}"
then
  error "Failed to run container \"dblab_preprocess_${CLONE_PRE}\""
else
  info "Container \"dblab_preprocess_${CLONE_PRE}\" has been running"
fi

# check the availability of Postgres
declare -i attempts=( 120 )
while [[ "$(${_PSQL} -XAtc 'select 1' 2> /dev/null)" != "1" ]]; do
  if (( $((attempts -= 1)) == 0 )); then
    error  "Preprocess database is not ready."
  fi
  sleep 1
done

# MAIN
# some code here, for example:

# execute for all databases (except for templates)
DBNAME_LIST=$(
  ${_PSQL} \
    -XAtc "
      select
        datname
      from
        pg_database
      where
        not datistemplate
    " \
)

for db in ${DBNAME_LIST}; do
  info "Database: ${db}"

  # create extensions (if not already exists)
  for extension in pg_stat_statements pg_stat_kcache pg_wait_sampling; do
    if [[ $(
            ${_PSQL} \
              -d "${db}" \
              -XAtc "
                select
                  extname is not null
                from
                  pg_catalog.pg_extension
                where
                  extname = '${extension}'
            " \
            ) != 't' ]]; then
      if ! ${_PSQL} -d "${db}" -XAtc "
             create extension ${extension}
            " 1> /dev/null; then
        error "Failed to create extension \"${extension}\" in the database \"${db}\""
      else
        info "Extension \"${extension}\" has been created in the database \"${db}\""
      fi
    else
      info "Extension \"${extension}\" already created in the database \"${db}\""
    fi
  done

done

# stop PostgreSQL
info "Run checkpoint command [psql -XAtc \"CHECKPOINT\"]"
if ! ${_PSQL} -XAtc "CHECKPOINT" &> /dev/null; then
  error "Failed to execute a CHECKPOINT command"
fi

info "Stopping PostgreSQL instance [pg_ctl --wait --timeout=1800 -D /var/lib/dblab/data stop]"
if ! docker exec dblab_preprocess_"${CLONE_PRE}" \
  bash -c "
    su - postgres -c \"
      /usr/lib/postgresql/${POSTGRES_VERSION}/bin/pg_ctl \
        --wait \
        --timeout=1800 \
        -D /var/lib/dblab/data \
        stop \
      \"
  " 1> /dev/null; then
  error "Failed to stop the Postgres instance in the container \"dblab_preprocess_${CLONE_PRE}\""
else
  info "The Postgres instance has been stopped"
fi

# stop Docker container dblab_preprocess
info "Stopping container: dblab_preprocess_${CLONE_PRE}"
if ! docker stop dblab_preprocess_"${CLONE_PRE}" &> /dev/null; then
  error "Failed to stop container \"dblab_preprocess_${CLONE_PRE}\""
else
  info "Container \"dblab_preprocess_${CLONE_PRE}\" has been stopped"
fi