Module: Railbow::MultiDb

Defined in:
lib/railbow/multi_db.rb

Overview

Rails runs db:migrate:status once per database, inside with_temporary_pool_for_each. Each call on its own cannot know whether more databases are coming, so railbow wraps that loop: sections collect into the open batch and the batch renders them together when the loop ends.

A batch is inert unless something adds to it, so wrapping the other tasks that share the same Rails helper (db:migrate, db:prepare) costs one object.

Defined Under Namespace

Classes: Batch

Constant Summary collapse

KEY = 
:railbow_multi_db_batch

Class Method Summary collapse

Class Method Details

.batch ⇒ Object

Opens a batch for the duration of the block. The flush is in an ensure so that a database aborting mid-run (a missing schema_migrations table, say) still prints the sections collected before it.



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# File 'lib/railbow/multi_db.rb', line 65

def batch
  previous = Thread.current[KEY]
  batch = Batch.new
  Thread.current[KEY] = batch
  begin
    yield
  ensure
    Thread.current[KEY] = previous
    batch.flush
  end
end

.claim_help ⇒ Object

True the first time it is asked within a run. Without a batch every call is its own run, so the answer is always true.



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# File 'lib/railbow/multi_db.rb', line 83

def claim_help
  current ? current.claim_help : true
end

.current ⇒ Object 



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# File 'lib/railbow/multi_db.rb', line 77

def current
  Thread.current[KEY]
end