Class: PerfectSched::RDBBackend

Inherits:
Backend
  • Object
show all
Defined in:
lib/perfectsched/backend/rdb.rb

Constant Summary collapse

MAX_SELECT_ROW = 
4

Instance Method Summary collapse

Methods inherited from Backend

#add, #close, #modify, #modify_data, #modify_sched

Constructor Details

#initialize(uri, table) ⇒ RDBBackend

Returns a new instance of RDBBackend.



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# File 'lib/perfectsched/backend/rdb.rb', line 6

def initialize(uri, table)
  super()
  require 'sequel'
  @uri = uri
  @table = table
  @db = Sequel.connect(@uri)
  init_db(@uri.split('//',2)[0])
end

Instance Method Details

#acquire(timeout, now = Time.now.to_i) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 63

def acquire(timeout, now=Time.now.to_i)
  connect {
    while true
      rows = 0
      @db.fetch("SELECT id, timeout, next_time, cron, delay, data FROM `#{@table}` WHERE timeout <= ? ORDER BY timeout ASC LIMIT #{MAX_SELECT_ROW};", now) {|row|

        n = @db["UPDATE `#{@table}` SET timeout=? WHERE id=? AND timeout=?;", timeout, row[:id], row[:timeout]].update
        salt = timeout
        if n > 0
          return [row[:id],salt], Task.new(row[:id], row[:next_time], row[:cron], row[:delay], row[:data])
        end

        rows += 1
      }
      if rows < MAX_SELECT_ROW
        return nil
      end
    end
  }
end

#add_checked(id, cron, delay, data, next_time, timeout) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 92

def add_checked(id, cron, delay, data, next_time, timeout)
  connect {
    begin
      n = @db["INSERT INTO `#{@table}` (id, timeout, next_time, cron, delay, data) VALUES (?, ?, ?, ?, ?, ?);", id, timeout, next_time, cron, delay, data].insert
      return true
    rescue Sequel::DatabaseError
      return nil
    end
  }
end

#delete(id) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 103

def delete(id)
  connect {
    n = @db["DELETE FROM `#{@table}` WHERE id=?;", id].delete
    return n > 0
  }
end

#finish(token, next_time, timeout) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 84

def finish(token, next_time, timeout)
  connect {
    id, salt = *token
    n = @db["UPDATE `#{@table}` SET timeout=?, next_time=? WHERE id=? AND timeout=?;", timeout, next_time, id, salt].update
    return n > 0
  }
end

#get(id) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 110

def get(id)
  connect {
    @db.fetch("SELECT id, timeout, next_time, cron, delay, data FROM `#{@table}` WHERE id=?;", id) {|row|
      return row[:cron], row[:delay], row[:data]
    }
    return nil
  }
end

#list(&block) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 55

def list(&block)
  @db.fetch("SELECT id, timeout, next_time, cron, delay, data FROM `#{@table}` ORDER BY timeout ASC") {|row|
    yield row[:id], row[:cron], row[:delay], row[:data], row[:next_time], row[:timeout]
  }
end

#modify_checked(id, cron, delay, data) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 119

def modify_checked(id, cron, delay, data)
  connect {
    n = @db["UPDATE `#{@table}` SET cron=?, delay=?, data=? WHERE id=?;", cron, delay, data, id].update
    return n > 0
  }
end

#modify_data_checked(id, data) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 133

def modify_data_checked(id, data)
  connect {
    n = @db["UPDATE `#{@table}` SET data=? WHERE id=?;", data, id].update
    return n > 0
  }
end

#modify_sched_checked(id, cron, delay) ⇒ Object 



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# File 'lib/perfectsched/backend/rdb.rb', line 126

def modify_sched_checked(id, cron, delay)
  connect {
    n = @db["UPDATE `#{@table}` SET cron=?, delay=? WHERE id=?;", cron, delay, id].update
    return n > 0
  }
end