backup.sh

#! /bin/sh

set -eu
set -o pipefail

if [ -z "$S3_ACCESS_KEY_ID" ]; then
  echo "You need to set the S3_ACCESS_KEY_ID environment variable."
  exit 1
fi

if [ -z "$S3_SECRET_ACCESS_KEY" ]; then
  echo "You need to set the S3_SECRET_ACCESS_KEY environment variable."
  exit 1
fi

if [ -z "$S3_BUCKET" ]; then
  echo "You need to set the S3_BUCKET environment variable."
  exit 1
fi

if [ -z "$POSTGRES_DATABASE" ]; then
  echo "You need to set the POSTGRES_DATABASE environment variable."
  exit 1
fi

if [ -z "$POSTGRES_HOST" ]; then
  if [ -n "$POSTGRES_PORT_5432_TCP_ADDR" ]; then
    POSTGRES_HOST=$POSTGRES_PORT_5432_TCP_ADDR
    POSTGRES_PORT=$POSTGRES_PORT_5432_TCP_PORT
  else
    echo "You need to set the POSTGRES_HOST environment variable."
    exit 1
  fi
fi

if [ -z "$POSTGRES_USER" ]; then
  echo "You need to set the POSTGRES_USER environment variable."
  exit 1
fi

if [ -z "$POSTGRES_PASSWORD" ]; then
  echo "You need to set the POSTGRES_PASSWORD environment variable."
  exit 1
fi

if [ -z "$S3_ENDPOINT" ]; then
  aws_args=""
else
  aws_args="--endpoint-url $S3_ENDPOINT"
fi


export AWS_ACCESS_KEY_ID=$S3_ACCESS_KEY_ID
export AWS_SECRET_ACCESS_KEY=$S3_SECRET_ACCESS_KEY
export AWS_DEFAULT_REGION=$S3_REGION
export PGPASSWORD=$POSTGRES_PASSWORD

echo "Creating backup of $POSTGRES_DATABASE database..."
pg_dump --format=custom \
        -h $POSTGRES_HOST \
        -p $POSTGRES_PORT \
        -U $POSTGRES_USER \
        -d $POSTGRES_DATABASE \
        $PGDUMP_EXTRA_OPTS \
        > db.dump

timestamp=$(date +"%Y-%m-%dT%H:%M:%S")
s3_uri_base="s3://${S3_BUCKET}/${S3_PREFIX}/${POSTGRES_DATABASE}_${timestamp}.dump"

if [ -n "$PASSPHRASE" ]; then
  echo "Encrypting backup..."
  gpg --symmetric --batch --passphrase "$PASSPHRASE" db.dump
  rm db.dump
  local_file="db.dump.gpg"
  s3_uri="${s3_uri_base}.gpg"
else
  local_file="db.dump"
  s3_uri="$s3_uri_base"
fi

echo "Uploading backup to $S3_BUCKET..."
aws $aws_args s3 cp "$local_file" "$s3_uri"
rm "$local_file"

echo "Backup complete."

if [ -n "$BACKUP_KEEP_DAYS" ]; then
  sec=$((86400*BACKUP_KEEP_DAYS))
  date_from_remove=$(date -d "@$(($(date +%s) - sec))" +%Y-%m-%d)
  backups_query="Contents[?LastModified<='${date_from_remove} 00:00:00'].{Key: Key}"

  echo "Removing old backup from $S3_BUCKET..."
  aws s3api list-objects \
    --bucket "${S3_BUCKET}" \
    --prefix "${S3_PREFIX}" \
    --query "${backups_query}" \
    --output text \
    | xargs -n1 -t -I 'KEY' aws s3 rm s3://"${S3_BUCKET}"/'KEY'
  echo "Removing complete."
fi