import random
descriptors = list()
Random_Max = 50
Constant_Value = 50

def Random_Numbers(name):
    '''Return a random number.'''
    global Random_Max
    return int(random.uniform(0,Random_Max))

def Constant_Number(name):
    '''Return a constant number.'''
    global Constant_Value
    return int(Constant_Value)

def metric_init(params):
    '''Initialize the random number generator and create the
    metric definition dictionary object for each metric.'''
    global descriptors
    global Random_Max
    global Constant_Value
    random.seed()

    print '[pyexample] Received the following parameters'
    print params

    if 'RandomMax' in params:
        Random_Max = int(params['RandomMax'])
    if 'ConstantValue' in params:
        Constant_Value = int(params['ConstantValue'])

    d1 = {'name': 'PyRandom_Numbers',
        'call_back': Random_Numbers,
        'time_max': 90,
        'value_type': 'uint',
        'units': 'N',
        'slope': 'both',
        'format': '%u',
        'description': 'Example module metric (random numbers)',
        'groups': 'example,random'}

    d2 = {'name': 'PyConstant_Number',
        'call_back': Constant_Number,
        'time_max': 90,
        'value_type': 'uint',
        'units': 'N',
        'slope': 'zero',
        'format': '%hu',
        'description': 'Example module constant (constant number)'}

    descriptors = [d1,d2]
    return descriptors

def metric_cleanup():
    '''Clean up the metric module.'''
    pass

#This code is for debugging and unit testing    
if __name__ == '__main__':
    params = {'RandomMax': '500',
        'ConstantValue': '322'}
    metric_init(params)
    for d in descriptors:
        v = d['call_back'](d['name'])
        print 'value for %s is %u' % (d['name'],  v)

     d1 = {'name': 'PyRandom_Numbers',             #metric的名字
        'call_back': Random_Numbers,    #收集到数据后调用的方法
        'time_max': 90,               #没有什么用。。。
        'value_type': 'uint',         #string | uint | float | double
        'units': 'N',                 # metric的单位
        'slope': 'both',              #zero | positive | negative | both
        'format': '%u',               #必须和value_type对应 (reference: http://docs.python.org/library/stdtypes.html#string-formatting)
        'description': 'Example module metric (random numbers)',    #对metric的描述，在前端可以看到
        'groups': 'example,random'}           #这个metric属于的组,如果没有定义，会分到no_group metric中

 modules{

  module {

    name = "example"

    language = "python"

    # The following params are examples only

    #  They are not actually used by the temp module

    param RandomMax {

      value = 600

    }

    param ConstantValue {

      value = 112

    }

  }

}

collection_group {

  collect_every = 10

  time_threshold = 50

  metric {

    name = "PyRandom_Numbers"
   #要显示的metric，与example.py中的d1名字对应
    title = "Random"
            #metric在网页上显示的标题
    value_threshold = 70

  }

  metric {

    name = "PyConstant_Number"
  #要显示的metric，与example.py中的d2名字对应
    title = "Constant"
          #metric在网页上显示的标题
    value_threshold = 70

  }

}