migrate mongdb, read from and to database properties from .env file

readme.md

base migrate.sh # by default read variables like `FROM_DB_URI` (the connection string) from `.env` file.
bash migrate.sh --env .env.prod # specify other env config file

Environment variables

The env file should contains the following variables.

FROM_DB_URI="mongodb://mongodb0.example.com:27017"
FROM_DB_USERNAME="username"
FROM_DB_PASSWORD="password"
FROM_DB_NAME="from-db-name"


TO_DB_URI="mongodb://mongodb0.example.com:27017"
TO_DB_USERNAME="username"
TO_DB_PASSWORD="password"
TO_DB_NAME="to-db-name"

migrate-mongdb.sh

#!/bin/bash

# Default .env file
ENV_FILE=".env"

# Parse arguments
while [[ "$#" -gt 0 ]]; do
  case $1 in
    --env) ENV_FILE="$2"; shift ;; # Set the environment file
    *) echo "Unknown parameter passed: $1"; exit 1 ;;
  esac
  shift
done

# Load environment variables from the specified .env file if it exists
if [ -f "$ENV_FILE" ]; then
  echo "Loading environment variables from $ENV_FILE"
  set -o allexport
  source "$ENV_FILE"
  set +o allexport
else
  echo "Environment file $ENV_FILE not found!"
  exit 1
fi

DUMP_DIR="./backup"
rm -rf $DUMP_DIR
mkdir -p $DUMP_DIR

mongodump --uri=$FROM_DB_URI --username=$FROM_DB_USERNAME --password=$FROM_DB_PASSWORD -d $FROM_DB_NAME --out $DUMP_DIR

if [ -d "${DUMP_DIR}/${FROM_DB_NAME}" ]; then
  mongorestore --uri=$TO_DB_URI --username=$TO_DB_USERNAME --password=$TO_DB_PASSWORD --nsFrom="${db_name}.*" --nsTo="${TO_DB_NAME}.*" "${DUMP_DIR}"
fi