Sequel Rake Tasks

sequel.rake

require 'sequel'
require 'yaml'
require 'erb'

Sequel.extension :migration
Sequel.extension :pg_array_ops, :pg_json_ops, :pg_hstore_ops

SEQUEL_MIGRATIONS_PATH = './db/migrate'

def database_name
  @database_name ||= URI.parse(Nenv.database_url).path.sub(%r[^/], "")
end

def db
  @db ||= begin
    db = Sequel.connect(Nenv.database_url)
    db.extension :pg_hstore, :pg_array, :pg_json
  end
end

namespace :db do
  desc "Create DB"
  task :create do |_, args|
    db.execute "CREATE DATABASE #{database_name}"
    puts "DB #{database_name} created"
  end

  desc "Drop DB"
  task :drop do |_, args|
    db.execute "DROP DATABASE #{database_name}"
    puts "DB #{database_name} dropped"
  end

  desc "Migrate DB"
  task :migrate do |_, args|
    before = db.from(:schema_migrations).all rescue []

    Sequel::Migrator.run(db, SEQUEL_MIGRATIONS_PATH)
    after = db.from(:schema_migrations).all

    puts "Migrated: #{(after - before).collect{|x| x[:filename]}.join(", ")}"
  end

  desc "Rollback Migration"
  task :rollback do |_, args|
    all_migrations_files = db.from(:schema_migrations).all

    previous_to_last_migration = if all_migrations_files.length == 1
      0
    else
      filename = all_migrations_files[-2][:filename]

      filename[/^\d+/].to_i
    end

    puts "rollback to #{previous_to_last_migration}"

    Sequel::Migrator.run(db, SEQUEL_MIGRATIONS_PATH, target: previous_to_last_migration)
  end

  desc "Generate migration"
  task :migration, [:name, :updown] do |_, args|
    next unless args[:name]

    content = "# migration #{args[:name]}\n\n"

    content << if args[:updown]
      "Sequel.migration do\n  up do\n    \n  end\n\n  down do\n    \n  end\nend\n"
    else
      "Sequel.migration do\n  change do\n    \n  end\nend\n"
    end

    timestamp = Time.now.strftime("%Y%m%d%H%M%S")
    filename = File.join(SEQUEL_MIGRATIONS_PATH, "#{timestamp}_#{args[:name]}.rb")

    File.open(filename, 'w') do |f|
      f.puts content
    end

    puts "Created Sequel migration #{filename}"
  end

  desc "Erase DB"
  task :erase do |_, args|
    db.tables.each { |table| db.drop_table table }
    puts "DB erased."
  end

  desc "Reset DB"
  task :reset do |_, args|
    Rake::Task["db:erase"].invoke
    Rake::Task["db:migrate"].invoke
    puts "DB reset."
  end

  namespace :schema do
    desc "Schema Dump"
    task :dump do
      db.extension :schema_dumper
      schema = db.dump_schema_migration
      open(ROOT + "/db/schema.rb", 'w') { |f| f << schema }
    end
  end
end