discourse/lib/tasks/db.rake

# frozen_string_literal: true

# we should set the locale before the migration
task 'set_locale' do
  begin
    I18n.locale = (SiteSetting.default_locale || :en) rescue :en
  rescue I18n::InvalidLocale
    I18n.locale = :en
  end
end

module MultisiteTestHelpers
  def self.load_multisite?
    Rails.env.test? && !ENV["RAILS_DB"] && !ENV["SKIP_MULTISITE"]
  end

  def self.create_multisite?
    (ENV["RAILS_ENV"] == "test" || !ENV["RAILS_ENV"]) && !ENV["RAILS_DB"] && !ENV["SKIP_MULTISITE"]
  end
end

task 'db:environment:set' => [:load_config]  do |_, args|
  if MultisiteTestHelpers.load_multisite?
    system("RAILS_ENV=test RAILS_DB=discourse_test_multisite rake db:environment:set")
  end
end

task 'db:force_skip_persist' do
  GlobalSetting.skip_db = true
  GlobalSetting.skip_redis = true
end

task 'db:create' => [:load_config] do |_, args|
  if MultisiteTestHelpers.create_multisite?
    unless system("RAILS_ENV=test RAILS_DB=discourse_test_multisite rake db:create")

      STDERR.puts "-" * 80
      STDERR.puts "ERROR: Could not create multisite DB. A common cause of this is a plugin"
      STDERR.puts "checking the column structure when initializing, which raises an error."
      STDERR.puts "-" * 80
      raise "Could not initialize discourse_test_multisite"
    end
  end
end

begin
  reqs = Rake::Task['db:create'].prerequisites.map(&:to_sym)
  Rake::Task['db:create'].clear_prerequisites
  Rake::Task['db:create'].enhance(["db:force_skip_persist"] + reqs)
end

task 'db:drop' => [:load_config] do |_, args|
  if MultisiteTestHelpers.create_multisite?
    system("RAILS_DB=discourse_test_multisite RAILS_ENV=test rake db:drop")
  end
end

begin
  Rake::Task["db:migrate"].clear
  Rake::Task["db:rollback"].clear
end

task 'db:rollback' => ['environment', 'set_locale'] do |_, args|
  step = ENV["STEP"] ? ENV["STEP"].to_i : 1
  ActiveRecord::Base.connection.migration_context.rollback(step)
  Rake::Task['db:_dump'].invoke
end

# our optimized version of multisite migrate, we have many sites and we have seeds
# this ensures we can run migrations concurrently to save huge amounts of time
Rake::Task['multisite:migrate'].clear

class StdOutDemux
  def initialize(stdout)
    @stdout = stdout
    @data = {}
  end

  def write(data)
    (@data[Thread.current] ||= +"") << data
  end

  def close
    finish_chunk
  end

  def finish_chunk
    data = @data[Thread.current]
    if data
      @stdout.write(data)
      @data.delete Thread.current
    end
  end

  def flush
    # Do nothing
  end
end

class SeedHelper
  def self.paths
    DiscoursePluginRegistry.seed_paths
  end

  def self.filter
    # Allows a plugin to exclude any specified seed data files from running
    DiscoursePluginRegistry.seedfu_filter.any? ?
      /^(?!.*(#{DiscoursePluginRegistry.seedfu_filter.to_a.join("|")})).*$/ : nil
  end
end

task 'multisite:migrate' => ['db:load_config', 'environment', 'set_locale'] do |_, args|
  if ENV["RAILS_ENV"] != "production"
    raise "Multisite migrate is only supported in production"
  end

  DistributedMutex.synchronize('db_migration', redis: Discourse.redis.without_namespace, validity: 1200) do
    # TODO: Switch to processes for concurrent migrations because Rails migration
    # is not thread safe by default.
    concurrency = 1

    puts "Multisite migrator is running using #{concurrency} threads"
    puts

    exceptions = Queue.new

    old_stdout = $stdout
    $stdout = StdOutDemux.new($stdout)

    SeedFu.quiet = true

    def execute_concurently(concurrency, exceptions)
      queue = Queue.new

      RailsMultisite::ConnectionManagement.each_connection do |db|
        queue << db
      end

      concurrency.times { queue << :done }

      (1..concurrency).map do
        Thread.new {
          while true
            db = queue.pop
            break if db == :done

            RailsMultisite::ConnectionManagement.with_connection(db) do
              begin
                yield(db) if block_given?
              rescue => e
                exceptions << [db, e]
              ensure
                begin
                  $stdout.finish_chunk
                rescue => ex
                  STDERR.puts ex.inspect
                  STDERR.puts ex.backtrace
                end
              end
            end
          end
        }
      end.each(&:join)
    end

    def check_exceptions(exceptions)
      if exceptions.length > 0
        STDERR.puts
        STDERR.puts "-" * 80
        STDERR.puts "#{exceptions.length} migrations failed!"
        while !exceptions.empty?
          db, e = exceptions.pop
          STDERR.puts
          STDERR.puts "Failed to migrate #{db}"
          STDERR.puts e.inspect
          STDERR.puts e.backtrace
          STDERR.puts
        end
        exit 1
      end
    end

    execute_concurently(concurrency, exceptions) do |db|
      puts "Migrating #{db}"
      ActiveRecord::Tasks::DatabaseTasks.migrate
    end

    check_exceptions(exceptions)

    SeedFu.seed(SeedHelper.paths, /001_refresh/)

    execute_concurently(concurrency, exceptions) do |db|
      puts "Seeding #{db}"
      SeedFu.seed(SeedHelper.paths, SeedHelper.filter)

      if !Discourse.skip_post_deployment_migrations? && ENV['SKIP_OPTIMIZE_ICONS'] != '1'
        SiteIconManager.ensure_optimized!
      end
    end

    $stdout = old_stdout
    check_exceptions(exceptions)

    Rake::Task['db:_dump'].invoke
  end
end

# we need to run seed_fu every time we run rake db:migrate
task 'db:migrate' => ['load_config', 'environment', 'set_locale'] do |_, args|
  DistributedMutex.synchronize('db_migration', redis: Discourse.redis.without_namespace, validity: 300) do
    migrations = ActiveRecord::Base.connection.migration_context.migrations
    now_timestamp = Time.now.utc.strftime('%Y%m%d%H%M%S').to_i
    epoch_timestamp = Time.at(0).utc.strftime('%Y%m%d%H%M%S').to_i

    raise "Migration #{migrations.last.version} is timestamped in the future" if migrations.last.version > now_timestamp
    raise "Migration #{migrations.first.version} is timestamped before the epoch" if migrations.first.version < epoch_timestamp

    ActiveRecord::Tasks::DatabaseTasks.migrate

    if !Discourse.is_parallel_test?
      Rake::Task['db:_dump'].invoke
    end

    SeedFu.quiet = true
    SeedFu.seed(SeedHelper.paths, SeedHelper.filter)

    if Rails.env.development?
      Rake::Task['db:schema:cache:dump'].invoke
    end

    if !Discourse.skip_post_deployment_migrations? && ENV['SKIP_OPTIMIZE_ICONS'] != '1'
      SiteIconManager.ensure_optimized!
    end
  end

  if !Discourse.is_parallel_test? && MultisiteTestHelpers.load_multisite?
    system("RAILS_DB=discourse_test_multisite rake db:migrate")
  end
end

task 'test:prepare' => 'environment' do
  I18n.locale = SiteSetting.default_locale rescue :en
  SeedFu.seed(DiscoursePluginRegistry.seed_paths)
end

task 'db:api_test_seed' => 'environment' do
  puts "Loading test data for discourse_api"
  load Rails.root + 'db/api_test_seeds.rb'
end

def print_table(array)
  width = array[0].keys.map { |k| k.to_s.length }
  cols = array[0].keys.length

  array.each do |row|
    row.each_with_index do |(_, val), i|
      width[i] = [width[i].to_i, val.to_s.length].max
    end
  end

  array[0].keys.each_with_index do |col, i|
    print col.to_s.ljust(width[i], ' ')
    if i == cols - 1
      puts
    else
      print ' | '
    end
  end

  puts "-" * (width.sum + width.length)

  array.each do |row|
    row.each_with_index do |(_, val), i|
      print val.to_s.ljust(width[i], ' ')
      if i == cols - 1
        puts
      else
        print ' | '
      end
    end
  end
end

desc 'Statistics about database'
task 'db:stats' => 'environment' do

  sql = <<~SQL
    select table_name,
    (
      select reltuples::bigint
      from pg_class
      where oid = ('public.' || table_name)::regclass
    ) AS row_estimate,
    pg_size_pretty(pg_table_size(quote_ident(table_name))) table_size,
    pg_size_pretty(pg_indexes_size(quote_ident(table_name))) index_size,
    pg_size_pretty(pg_total_relation_size(quote_ident(table_name))) total_size
    from information_schema.tables
    where table_schema = 'public'
    order by pg_total_relation_size(quote_ident(table_name)) DESC
  SQL

  puts
  print_table(DB.query_hash(sql))
end

task 'db:ensure_post_migrations' do
  if ['1', 'true'].include?(ENV['SKIP_POST_DEPLOYMENT_MIGRATIONS'])
    cmd = `cat /proc/#{Process.pid}/cmdline | xargs -0 echo`
    ENV["SKIP_POST_DEPLOYMENT_MIGRATIONS"] = "0"
    exec cmd
  end
end

class NormalizedIndex
  attr_accessor :name, :original, :normalized, :table

  def initialize(original)
    @original = original
    @normalized = original.sub(/(create.*index )(\S+)(.*)/i, '\1idx\3')
    @name = original.match(/create.*index (\S+)/i)[1]
    @table = original.match(/create.*index \S+ on public\.(\S+)/i)[1]
  end

  def ==(other)
    other&.normalized == normalized
  end
end

def normalize_index_names(names)
  names.map do |name|
    NormalizedIndex.new(name)
  end.reject { |i| i.name.include?("ccnew") }
end

desc 'Validate indexes'
task 'db:validate_indexes', [:arg] => ['db:ensure_post_migrations', 'environment'] do |_, args|

  db = TemporaryDb.new
  db.start
  db.migrate

  ActiveRecord::Base.establish_connection(
    adapter: 'postgresql',
    database: 'discourse',
    port: db.pg_port,
    host: 'localhost'
  )

  expected = DB.query_single <<~SQL
    SELECT indexdef FROM pg_indexes
    WHERE schemaname = 'public'
    ORDER BY indexdef
  SQL

  expected_tables = DB.query_single <<~SQL
    SELECT tablename
    FROM pg_tables
    WHERE schemaname = 'public'
  SQL

  ActiveRecord::Base.establish_connection

  db.stop

  puts

  fix_indexes = (ENV["FIX_INDEXES"] == "1" || args[:arg] == "fix")
  inconsistency_found = false

  RailsMultisite::ConnectionManagement.each_connection do |db_name|

    puts "Testing indexes on the #{db_name} database", ""

    current = DB.query_single <<~SQL
      SELECT indexdef FROM pg_indexes
      WHERE schemaname = 'public'
      ORDER BY indexdef
    SQL

    missing = expected - current
    extra = current - expected

    extra.reject! { |x| x =~ /idx_recent_regular_post_search_data/ }

    renames = []
    normalized_missing = normalize_index_names(missing)
    normalized_extra = normalize_index_names(extra)

    normalized_extra.each do |extra_index|
      if missing_index = normalized_missing.select { |x| x == extra_index }.first
        renames << [extra_index, missing_index]
        missing.delete missing_index.original
        extra.delete extra_index.original
      end
    end

    if db_name != "default" && renames.length == 0 && missing.length == 0 && extra.length == 0
      next
    end

    if renames.length > 0
      inconsistency_found = true

      puts "Renamed indexes"
      renames.each do |extra_index, missing_index|
        puts "#{extra_index.name} should be renamed to #{missing_index.name}"
      end
      puts

      if fix_indexes
        puts "fixing indexes"

        renames.each do |extra_index, missing_index|
          DB.exec "ALTER INDEX #{extra_index.name} RENAME TO #{missing_index.name}"
        end

        puts
      end
    end

    if missing.length > 0
      inconsistency_found = true

      puts "Missing Indexes", ""
      missing.each do |m|
        puts m
      end
      if fix_indexes
        puts "Adding missing indexes..."
        missing.each do |m|
          begin
            DB.exec(m)
          rescue => e
            $stderr.puts "Error running: #{m} - #{e}"
          end
        end
      end
    else
      puts "No missing indexes", ""
    end

    if extra.length > 0
      inconsistency_found = true

      puts "", "Extra Indexes", ""
      extra.each do |e|
        puts e
      end

      if fix_indexes
        puts "Removing extra indexes"
        extra.each do |statement|
          if match = /create .*index (\S+) on public\.(\S+)/i.match(statement)
            index_name, table_name = match[1], match[2]
            if expected_tables.include?(table_name)
              puts "Dropping #{index_name}"
              begin
                DB.exec("DROP INDEX #{index_name}")
              rescue => e
                $stderr.puts "Error dropping index #{index_name} - #{e}"
              end
            else
              $stderr.puts "Skipping #{index_name} since #{table_name} should not exist - maybe an old plugin created it"
            end
          else
            $stderr.puts "ERROR - BAD REGEX - UNABLE TO PARSE INDEX - #{statement}"
          end
        end
      end
    else
      puts "No extra indexes", ""
    end
  end

  if inconsistency_found && !fix_indexes
    exit 1
  end
end

desc 'Rebuild indexes'
task 'db:rebuild_indexes' => 'environment' do
  if Import::backup_tables_count > 0
    raise "Backup from a previous import exists. Drop them before running this job with rake import:remove_backup, or move them to another schema."
  end

  Discourse.enable_readonly_mode

  backup_schema = Jobs::Importer::BACKUP_SCHEMA
  table_names = DB.query_single("select table_name from information_schema.tables where table_schema = 'public'")

  begin
    # Move all tables to the backup schema:
    DB.exec("DROP SCHEMA IF EXISTS #{backup_schema} CASCADE")
    DB.exec("CREATE SCHEMA #{backup_schema}")
    table_names.each do |table_name|
      DB.exec("ALTER TABLE public.#{table_name} SET SCHEMA #{backup_schema}")
    end

    # Create a new empty db
    Rake::Task["db:migrate"].invoke

    # Fetch index definitions from the new db
    index_definitions = {}
    table_names.each do |table_name|
      index_definitions[table_name] = DB.query_single("SELECT indexdef FROM pg_indexes WHERE tablename = '#{table_name}' and schemaname = 'public';")
    end

    # Drop the new tables
    table_names.each do |table_name|
      DB.exec("DROP TABLE public.#{table_name}")
    end

    # Move the old tables back to the public schema
    table_names.each do |table_name|
      DB.exec("ALTER TABLE #{backup_schema}.#{table_name} SET SCHEMA public")
    end

    # Drop their indexes
    index_names = DB.query_single("SELECT indexname FROM pg_indexes WHERE schemaname = 'public' AND tablename IN ('#{table_names.join("', '")}')")
    index_names.each do |index_name|
      begin
        puts index_name
        DB.exec("DROP INDEX public.#{index_name}")
      rescue ActiveRecord::StatementInvalid
        # It's this:
        # PG::Error: ERROR:  cannot drop index category_users_pkey because constraint category_users_pkey on table category_users requires it
        # HINT:  You can drop constraint category_users_pkey on table category_users instead.
      end
    end

    # Create the indexes
    table_names.each do |table_name|
      index_definitions[table_name].each do |index_def|
        begin
          DB.exec(index_def)
        rescue ActiveRecord::StatementInvalid
          # Trying to recreate a primary key
        end
      end
    end
  rescue
    # Can we roll this back?
    raise
  ensure
    Discourse.disable_readonly_mode
  end
end

desc 'Check that the DB can be accessed'
task 'db:status:json' do
  begin
    Rake::Task['environment'].invoke
    DB.query('SELECT 1')
  rescue
    puts({ status: 'error' }.to_json)
  else
    puts({ status: 'ok' }.to_json)
  end
end