Class: ActiveRecord::Migrator

Inherits:
Object
  • Object
show all
Defined in:
lib/active_record_shards/migration.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.shard_status(versions) ⇒ Object

public list of pending and missing versions per shard

=> [1234567], => [2345678] 


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# File 'lib/active_record_shards/migration.rb', line 62

def self.shard_status(versions)
  pending = {}
  missing = {}

  collect = lambda do |shard|
    migrated = shards_migration_context.get_all_versions

    p = versions - migrated
    pending[shard] = p if p.any?

    m = migrated - versions
    missing[shard] = m if m.any?
  end

  ActiveRecord::Base.on_shard(nil) { collect.call(nil) }
  ActiveRecord::Base.on_all_shards { |shard| collect.call(shard) }

  [pending, missing]
end

.shards_migration_context ⇒ Object 



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# File 'lib/active_record_shards/migration.rb', line 4

def self.shards_migration_context
  if ActiveRecord::VERSION::STRING >= '5.2.0'
    ActiveRecord::MigrationContext.new(['db/migrate'])
  else
    self
  end
end

Instance Method Details

#initialize_with_sharding(*args) ⇒ Object Also known as: initialize 



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# File 'lib/active_record_shards/migration.rb', line 12

def initialize_with_sharding(*args)
  initialize_without_sharding(*args)

  # Rails creates the internal tables on the unsharded DB. We make them
  # manually on the sharded DBs.
  ActiveRecord::Base.on_all_shards do
    if ActiveRecord::VERSION::MAJOR >= 4
      ActiveRecord::SchemaMigration.create_table
    else
      ActiveRecord::Base.connection.initialize_schema_migrations_table
    end
    if ActiveRecord::VERSION::MAJOR >= 5
      ActiveRecord::InternalMetadata.create_table
    end
  end
end

#migrate_with_sharding ⇒ Object Also known as: migrate 



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# File 'lib/active_record_shards/migration.rb', line 38

def migrate_with_sharding
  ActiveRecord::Base.on_shard(nil) { migrate_without_sharding }
  ActiveRecord::Base.on_all_shards { migrate_without_sharding }
end

#migrated ⇒ Object 



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# File 'lib/active_record_shards/migration.rb', line 47

def migrated
  self.class.shards_migration_context.get_all_versions
end

#pending_migrations ⇒ Object 



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# File 'lib/active_record_shards/migration.rb', line 53

def pending_migrations
  pending, _missing = self.class.shard_status(migrations.map(&:version))
  pending = pending.values.flatten
  migrations.select { |m| pending.include?(m.version) }
end

#run_with_sharding ⇒ Object Also known as: run 



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# File 'lib/active_record_shards/migration.rb', line 31

def run_with_sharding
  ActiveRecord::Base.on_shard(nil) { run_without_sharding }
  ActiveRecord::Base.on_all_shards { run_without_sharding }
end