Class: PgMigrate::Migrator

Inherits:
Object
  • Object
show all
Defined in:
lib/pg_migrate/migrator.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(manifest_reader, sql_reader, options = {}) ⇒ Migrator

options = gem ‘pg’ connection_hash options, or connstring => dbname=test port=5432, or pgconn => PG::Connection object



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# File 'lib/pg_migrate/migrator.rb', line 8

def initialize(manifest_reader, sql_reader, options = {})
  @log = Logging.logger[self]
  @connection_hash = options
  @manifest = nil
  @builder_version = nil
  @manifest_reader = manifest_reader
  @sql_reader = sql_reader
end

Instance Attribute Details

#conn ⇒ Object

Returns the value of attribute conn.



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# File 'lib/pg_migrate/migrator.rb', line 5

def conn
  @conn
end

#connection_hash ⇒ Object

Returns the value of attribute connection_hash.



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# File 'lib/pg_migrate/migrator.rb', line 5

def connection_hash
  @connection_hash
end

#manifest ⇒ Object

Returns the value of attribute manifest.



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# File 'lib/pg_migrate/migrator.rb', line 5

def manifest
  @manifest
end

#manifest_path ⇒ Object

Returns the value of attribute manifest_path.



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# File 'lib/pg_migrate/migrator.rb', line 5

def manifest_path
  @manifest_path
end

#manifest_reader ⇒ Object

Returns the value of attribute manifest_reader.



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# File 'lib/pg_migrate/migrator.rb', line 5

def manifest_reader
  @manifest_reader
end

#sql_reader ⇒ Object

Returns the value of attribute sql_reader.



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# File 'lib/pg_migrate/migrator.rb', line 5

def sql_reader
  @sql_reader
end

Instance Method Details

#execute_migration(name, filepath) ⇒ Object

execute a single migration by loading it’s statements from file, and then executing each



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# File 'lib/pg_migrate/migrator.rb', line 63

def execute_migration(name, filepath)
  @log.info "executing migration #{filepath}"

  statements = @sql_reader.load_migration(filepath)
  if statements.length == 0
    raise 'no statements found in migration #{filepath}'
  end
  run_migration(name, statements)
end

#migrate(manifest_path) ⇒ Object

‘migrate’ attempt to migrate your database based on the contents of your built manifest The manifest_path argument should point to your manifest manifest_path = the directory containing your ‘manifest’ file, ‘up’ directory, ‘down’ directory, ‘test’ directory this method will throw an exception if anything goes wrong (such as bad SQL in the migrations themselves)



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# File 'lib/pg_migrate/migrator.rb', line 21

def migrate(manifest_path)
  @manifest_path = manifest_path

  @conn = Util::get_conn(@connection_hash)

  # this is used to record the version of the 'migrator' in the pg_migrate table
  @conn.exec("SET application_name = 'pg_migrate_ruby-#{PgMigrate::VERSION}'")

  # load the manifest, and version of the builder that made it
  process_manifest()

  # execute the migrations
  run_migrations(@manifest)
end

#process_manifest ⇒ Object

load the manifest’s migration declarations, and validate that each migration points to a real file



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# File 'lib/pg_migrate/migrator.rb', line 38

def process_manifest
  @manifest, @builder_version = @manifest_reader.load_output_manifest(@manifest_path)
  @manifest_reader.validate_migration_paths(@manifest_path, @manifest)
end

#run_bootstrap ⇒ Object

executes the bootstrap method



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# File 'lib/pg_migrate/migrator.rb', line 57

def run_bootstrap
  bootstrap = File.join(@manifest_path, UP_DIRNAME, BOOTSTRAP_FILENAME)
  execute_migration('bootstrap.sql', bootstrap)
end

#run_migration(name, statements) ⇒ Object

execute all the statements of a single migration



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# File 'lib/pg_migrate/migrator.rb', line 74

def run_migration(name, statements)

  begin
    statements.each do |statement|
      conn.exec(statement).clear
    end
  rescue Exception => e
    # we make a special allowance for one exception; it just means this migration
    # has already occurred, and we should just treat it like a continue
    if e.message.index('pg_migrate: code=migration_exists').nil?
      conn.exec("ROLLBACK")
      raise e
    else
      conn.exec("ROLLBACK")
      @log.info "migration #{name} already run"
    end
  end
end

#run_migrations(manifest) ⇒ Object

run all necessary migrations



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# File 'lib/pg_migrate/migrator.rb', line 44

def run_migrations(manifest)

  # run bootstrap before user migrations to prepare database
  run_bootstrap

  # loop through the manifest, executing migrations in turn
  manifest.each_with_index do |migration, index|
    execute_migration(migration.name, migration.filepath)
  end

end