ActiveRecord::ModSqlLogSubscriber

An ActiveRecord::LogSubscriber which records only mod-SQL logs.

The mod-SQL is shown as follows.

INSERT
UPDATE
DELETE
TRUNCATE
BEGIN
COMMIT
ROLLBACK
SAVEPOINT
RELEASE SAVEPOINT
ROLLBACK TO SAVEPOINT

Motivation

SQL logs are useful for trouble shooging.
Especialy, mod-SQL(INSERT, UPDATE, DELETE, ...) logs are very important to know what occurred in app.
Rails provides SQL logging feature only by settings Rails.logger log level to :debug.
But this settings writes a lot of SELECT statement SQL logs. These logs are very noisy and use many disk space.
I want to write logs only mod-SQL(INSERT, UPDATE, DELETE, ...) and transaction SQL(BEGIN, COMMIT, ROLLBACK, ...). So I create this gem.

Requirements

Rails >= 5.1.5

Installation

Add this line to your application's Gemfile:

gem 'active_record-mod_sql_log_subscriber'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install active_record-mod_sql_log_subscriber

Usage

Create a file underconfig/initializer, configure log subscriber, and attach to :active_record namespace.

require 'active_record/mod_sql_log_subscriber'

::ActiveRecord::ModSqlLogSubscriber.configure do |config|
  config.disable = ::ActiveRecord::Base.logger.debug? # Recommended
end

::ActiveRecord::ModSqlLogSubscriber.attach_to(:active_record)

Next restart your app, then your app starts to log mod-SQLs.

Here is rails console examples.

$ rails c

> ActiveRecord::Base.logger = Logger.new(STDOUT)

> user = User.find(1); nil # Do not logging

> user.update_attributes(name: 'New name'); nil # Do logging
# => "UPDATE users SET name = 'New name' WHERE id = $1  {:id=>1}"

Try console

You can try this gem by cloning this repo and run bin/setup and bin/console.

$ git clone https://github.com/ryu39/active_record-mod_sql_log_subscriber.git
$ cd active_record-mod_sql_log_subscriber

# Run bundle install and create sqlite3 database.
$ bin/setup

# Connect sqlite3 database and start IRB.
$ bin/console

> User.count # => no log

> User.create!(name: 'name', age: 20, birth_date: Date.new(2000, 1, 1))
# => I, [2019-02-05T11:04:07.489057 #42019]  INFO -- : begin transaction
#    I, [2019-02-05T11:04:07.490495 #42019]  INFO -- : INSERT INTO "users" ("name", "age", "birth_date", "created_at", "updated_at") VALUES (?, ?, ?, ?, ?)  ["name", 20, "2000-01-01", "2019-02-20 05:00:13.175405", "2019-02-20 05:00:13.175405"]
#    I, [2019-02-05T11:04:07.492610 #42019]  INFO -- : commit transaction

> user = User.last # => no log
> user.update!(name: 'new name')
# => I, [2019-02-05T11:04:52.971503 #42019]  INFO -- : begin transaction
#    I, [2019-02-05T11:04:52.973071 #42019]  INFO -- : UPDATE "users" SET "name" = ?, "updated_at" = ? WHERE "users"."id" = ?  ["new name", "2019-02-20 05:00:37.983816", 2]
#    I, [2019-02-05T11:04:52.974081 #42019]  INFO -- : commit transaction

> user.destroy!
# => I, [2019-02-05T11:05:13.765564 #42019]  INFO -- : begin transaction
#    I, [2019-02-05T11:05:13.775460 #42019]  INFO -- : DELETE FROM "users" WHERE "users"."id" = ?  [2]
#    I, [2019-02-05T11:05:13.776722 #42019]  INFO -- : commit transaction

Configuration

You can configure this subscriber before attaching to :active_record namespace

::ActiveRecord::ModSqlLogSubscriber.configure do |config|
  config.disable = true
  config.log_level = :warn
  config.log_format = :json
  # config.log_format = ->(sql, binds) { 'your code here' }
  config.target_statements << 'merge'
end

# You must attach subscriber after configuraton.
::ActiveRecord::ModSqlLogSubscriber.attach_to(:active_record)

Enable/Disable

You can make log subscriber enbaled/disabled via config. Default is enabled. This is useful in development/test env because duplicated sql logs are written in log in this env.

::ActiveRecord::ModSqlLogSubscriber.configure do |config|
  config.disable = false # enabled
  config.disable = true # disabled

  config.disable = ::ActiveRecord::Base.logger.debug? # Recommended
end

Log level

You can change log level. Default is :info.

::ActiveRecord::ModSqlLogSubscriber.configure do |config|
  config.log_level = :warn
  # config.log_level = :error
  # config.log_level = :fatal
end

Log format

You can select log format as follows, or use a custom Proc object.

:text (Default)
:json
:hash
Proc object

Target statement

You can add/change/remove target SQL statements.

::ActiveRecord::ModSqlLogSubscriber.configure do |config|
  # Add MERGE SQL
  config.target_statements << 'merge'

  # Remove BEGIN SQL
  config.target_stagements.delete('begin')

  # Orverwite your target statements
  config.target_statements = %w(insert update delete)
end

Development

After checking out the repo, run bin/setup to install dependencies. 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 mod_sql_log_subscriber.r, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ryu39/active_record-mod_sql_log_subscriber. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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

Code of Conduct

Everyone interacting in the ActiveRecord::ModSqlLogSubscriber project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.