Export What I Want (Exwiw) is a Ruby gem that allows you to export records from a database to a dump file(to specifically, the full list of INSERT sql) on the specified conditions.

Most of case in developing a software, There is no better choice than the same data in production. You might make well-crafted data, but it's very very hard to maintain.

If you find the way to maintain the data for develoment env, then exwiw might be a solution for that.

• Export the full database and mask data and import to another database.
• Setup some system to replicate and mask data in real-time to another database.

You want to export only the data you want to export.

• Export the full list of INSERT sql for the specified conditions.
• Provide serveral masking options for sensitive columns.
• Provide config generator for ActiveRecord.

bundle add exwiw

Most of cases, you want to add 'require: false' to the Gemfile.

If bundler is not being used to manage dependencies, install the gem by executing:

gem install exwiw

• mysql2
• postgresql
• sqlite3

# dump & masking all records from database to dump.sql based on schema.json
# pass database password as an environment variable 'DATABASE_PASSWORD'
exwiw \
  --adapter=mysql2 \
  --host=localhost \
  --port=3306 \
  --user=reader \
  --database=app_production \
  --config-dir=exwiw \
  --target-table=shops \
  --ids=1 \ # comma separated ids
  --output-dir=dump \
  --log-level=info

This command will generate sql files in the dump directory.

• dump/insert-{idx}-{table_name}.sql
• dump/delete-{idx}-{table_name}.sql

idx means the order of the dump. bigger idx might depend on smaller idx, so you should import the dump in order.

you need to delete the records before importing the dump, delete-{idx}-{table_name}.sql will help you to do that. This sql will delete "all" related records to the extract targets. idx meaning is the same as insert sql.

The config generator is provided as a Rake task.

# generate table schema under exwiw/
bundle exec rake exwiw:schema:generate

By default, the schema files will be saved in the exwiw directory. You can specify a different output directory by setting the OUTPUT_DIR_PATH environment variable:

OUTPUT_DIR_PATH=custom_directory bundle exec rake exwiw:schema:generate

This is an example of the one table schema:

{
    "name": "users",
    "primary_key": "id",
    "filter": "users.id > 0",
    "belongs_to": [{
        "name": "companies",
        "foreign_key": "company_id"
    }],
    "columns": [{
        "name": "id",
    }, {
        "name": "email",
        "replace_with": "user{id}@example.com"
    }, {
        "name": "company_id"
    }]
}

--config-dir will use all json files in the specified directory.

Some case, you don't need full records related to target. e.g. dump user access logs only for the last year. filter is here for that. Be careful to use this option, as it will be:

• injected as it is in table condition(e.g. WHERE on mysql), so you are recommended to clearify table name of column to avoid ambiguity.
• injected to every where / join clause, so it affects to all tables depends on filterted target-table. it results to data inconsistency.

exwiw provides several options for masking value.

It will replace the value with the specified string, and you can use the column name with {} to replace the value with the column value.

For example, Let assume we have the record which id is 1, then "user{id}@example.com" will be replaced with "[email protected]".

It will used instead of the original value.

For example, "raw_sql": "CONCAT('user', shops.id, '@example.com')" is equivalent to "replace_with": "user{id}@example.com". This is useful when you want to transform with functions provided by the database.

Notice that you are recommended to clearify table name of column to avoid ambiguity.

If it used with replace_with, replace_with will be ignored.

XXX: TODO

Given value will be evaluated as Ruby code, and treated as the proc.

"map": "proc { |r| 'user' + v['id'].to_s + '@example.com' }"

which is equivalent to "replace_with": "user{id}@example.com".

Notice this is the most powerful option, but you should be careful to use this option. Because this transformation occured on exwiw process, so much slower than other options. Most of case, this option is not recommended.

• Load the table information from the specified config file.
• Calculate the dependency between tables.
• Generate the full list of INSERT sql based on the specified conditions.
  • If the processing table has no relation with target tables, then dump all records.
  • If the processing table has relation with target tables, then dump the records which are related to the target tables.
• Generate the full list of DELETE sql based on the specified conditions.
  • If the processing table has no relation with target tables, then delete all records.
  • If the processing table has relation with target tables, then delete the records which are related to the target tables.

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/riseshia/exwiw.

The gem is available as open source under the terms of the MIT License.