Class: OnlineMigrations::BackgroundMigrations::Config

Inherits:
Object
  • Object
show all
Defined in:
lib/online_migrations/background_migrations/config.rb

Overview

Class representing configuration options for background migrations.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Config

Returns a new instance of Config.



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# File 'lib/online_migrations/background_migrations/config.rb', line 81

def initialize
  @migrations_path = "lib"
  @migrations_module = "OnlineMigrations::BackgroundMigrations"
  @batch_size = 20_000
  @sub_batch_size = 1000
  @batch_pause = 0.seconds
  @sub_batch_pause_ms = 100
  @batch_max_attempts = 5
  @throttler = -> { false }
  @stuck_jobs_timeout = 1.hour
  @error_handler = ->(error, errored_job) {}
end

Instance Attribute Details

#backtrace_cleaner ⇒ ActiveSupport::BacktraceCleaner?

The Active Support backtrace cleaner that will be used to clean the backtrace of a migration job that errors.

Returns:

  • (ActiveSupport::BacktraceCleaner, nil) —

    the backtrace cleaner to use when cleaning a job's backtrace. Defaults to Rails.backtrace_cleaner



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# File 'lib/online_migrations/background_migrations/config.rb', line 66

def backtrace_cleaner
  @backtrace_cleaner
end

#batch_max_attempts ⇒ Integer

Maximum number of batch run attempts

When attempts are exhausted, the individual batch is marked as failed.

Returns:

  • (Integer) —

    defaults to 5



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# File 'lib/online_migrations/background_migrations/config.rb', line 40

def batch_max_attempts
  @batch_max_attempts
end

#batch_pause ⇒ Integer

The pause interval between each background migration job's execution (in seconds)

Returns:

  • (Integer) —

    defaults to 0



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# File 'lib/online_migrations/background_migrations/config.rb', line 28

def batch_pause
  @batch_pause
end

#batch_size ⇒ Integer

The number of rows to process in a single background migration run

Returns:

  • (Integer) —

    defaults to 20_000



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# File 'lib/online_migrations/background_migrations/config.rb', line 18

def batch_size
  @batch_size
end

#error_handler ⇒ Proc

The callback to perform when an error occurs in the migration job.

Examples:

OnlineMigrations.config.background_migrations.error_handler = ->(error, errored_job) do
  Bugsnag.notify(error) do |notification|
    notification.add_metadata(:background_migration, { name: errored_job.migration_name })
  end
end

Returns:

  • (Proc) —

    the callback to perform when an error occurs in the migration job



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# File 'lib/online_migrations/background_migrations/config.rb', line 79

def error_handler
  @error_handler
end

#migrations_module ⇒ String

The module in which background migrations will be placed

Returns:

  • (String) —

    defaults to "OnlineMigrations::BackgroundMigrations"



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# File 'lib/online_migrations/background_migrations/config.rb', line 13

def migrations_module
  @migrations_module
end

#migrations_path ⇒ String

The path where generated background migrations will be placed

Returns:

  • (String) —

    defaults to "lib"



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# File 'lib/online_migrations/background_migrations/config.rb', line 9

def migrations_path
  @migrations_path
end

#stuck_jobs_timeout ⇒ Integer

The number of seconds that must pass before the running job is considered stuck

Returns:

  • (Integer) —

    defaults to 1 hour



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# File 'lib/online_migrations/background_migrations/config.rb', line 58

def stuck_jobs_timeout
  @stuck_jobs_timeout
end

#sub_batch_pause_ms ⇒ Integer

The number of milliseconds to sleep between each sub_batch execution

Returns:

  • (Integer) —

    defaults to 100 milliseconds



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# File 'lib/online_migrations/background_migrations/config.rb', line 33

def sub_batch_pause_ms
  @sub_batch_pause_ms
end

#sub_batch_size ⇒ Integer

The smaller batches size that the batches will be divided into

Returns:

  • (Integer) —

    defaults to 1000



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# File 'lib/online_migrations/background_migrations/config.rb', line 23

def sub_batch_size
  @sub_batch_size
end

#throttler ⇒ Proc

Allows to throttle background migrations based on external signal (e.g. database health)

It will be called before each batch run. If throttled, the current run will be retried next time.

Examples:

OnlineMigrations.config.background_migrations.throttler = -> { DatabaseStatus.unhealthy? }

Returns:

  • (Proc) 


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# File 'lib/online_migrations/background_migrations/config.rb', line 52

def throttler
  @throttler
end