在本教程中，我们将看到如何处理正在运行的task的结果。
让我们从类似于我们已经看到的代码开始：
import logging
from nornir import InitNornir
from nornir.core.task import Task, Result
# instantiate the nr object
nr = InitNornir(config_file="config.yaml")
# let's filter it down to simplify the output
cmh = nr.filter(site="cmh", type="host")
def count(task: Task, number: int) -> Result:
return Result(
host=task.host,
result=f"{[n for n in range(0, number)]}"
)
def say(task: Task, text: str) -> Result:
if task.host.name == "host2.cmh":
raise Exception("I can't say anything right now")
return Result(
host=task.host,
result=f"{task.host.name} says {text}"
)
到目前为止，没有什么新鲜的东西，我们已经在saytask中对错误进行了硬编码，这将帮助我们说明一些概念。现在，让我们为在先前的教程中看到的分组task创建一个变体：
def greet_and_count(task: Task, number: int):
task.run(
name="Greeting is the polite thing to do",
severity_level=logging.DEBUG,
task=say,
text="hi!",
)
task.run(
name="Counting beans",
task=count,
number=number,
)
task.run(
name="We should say bye too",
severity_level=logging.DEBUG,
task=say,
text="bye!",
)
# let's inform if we counted even or odd times
even_or_odds = "even" if number % 2 == 1 else "odd"
return Result(
host=task.host,
result=f"{task.host} counted {even_or_odds} times!",
)
与我们之前的分组task几乎相同，只是我们传递severity_level=logging.DEBUG给第一个和最后一个子task的区别。稍后我们将了解这意味着什么。
现在，让我们调用task组，以便我们可以开始检查结果对象：
result = cmh.run(
task=greet_and_count,
number=5,
)
简单的方法
在大多数情况下，您只想提供有关正在发生的事情的反馈。为此，您可以使用软件包随附的print_result函数nornir_utils：
from nornir_utils.plugins.functions import print_result print_result(result)
greet_and_count*****************************************************************
* host1.cmh ** changed : False *************************************************
vvvv greet_and_count ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv INFO
host1.cmh counted even times!
---- Counting beans ** changed : False ----------------------------------------- INFO
[0, 1, 2, 3, 4]
^^^^ END greet_and_count ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* host2.cmh ** changed : False *************************************************
vvvv greet_and_count ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv ERROR
Subtask: Greeting is the polite thing to do (failed)
---- Greeting is the polite thing to do ** changed : False --------------------- ERROR
Traceback (most recent call last):
File "/home/dbarroso/workspace/dbarrosop/nornir/nornir/core/task.py", line 98, in start
r = self.task(self, **self.params)
File "<ipython-input-1-c084194db610>", line 19, in say
raise Exception("I can't say anything right now")
Exception: I can't say anything right now
^^^^ END greet_and_count ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
您还应该能够打印一个host：
print_result(result["host1.cmh"])
vvvv greet_and_count ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv INFO host1.cmh counted even times! ---- Counting beans ** changed : False ----------------------------------------- INFO [0, 1, 2, 3, 4] ^^^^ END greet_and_count ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
甚至是一个task：
print_result(result["host1.cmh"][2])
---- Counting beans ** changed : False ----------------------------------------- INFO [0, 1, 2, 3, 4]
可能已经注意到，并非所有task都已打印。这是由于severity_level我们通过了论证。这让我们用任何日志记录级别标记task。然后print_result可以遵循日志记录规则来打印结果。默认情况下，仅INFO打印标记为的task（如果未指定，这也是task的默认设置）。
失败的task将始终将其严重性级别更改为，ERROR而不管用户指定的级别如何。你可以看到，在task的。Greeting is the polite thing to dohost2.cmh
现在，让我们告诉print_result您打印标记为的taskDEBUG。
print_result(result, severity_level=logging.DEBUG)
greet_and_count*****************************************************************
* host1.cmh ** changed : False *************************************************
vvvv greet_and_count ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv INFO
host1.cmh counted even times!
---- Greeting is the polite thing to do ** changed : False --------------------- DEBUG
host1.cmh says hi!
---- Counting beans ** changed : False ----------------------------------------- INFO
[0, 1, 2, 3, 4]
---- We should say bye too ** changed : False ---------------------------------- DEBUG
host1.cmh says bye!
^^^^ END greet_and_count ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* host2.cmh ** changed : False *************************************************
vvvv greet_and_count ** changed : False vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv ERROR
Subtask: Greeting is the polite thing to do (failed)
---- Greeting is the polite thing to do ** changed : False --------------------- ERROR
Traceback (most recent call last):
File "/home/dbarroso/workspace/dbarrosop/nornir/nornir/core/task.py", line 98, in start
r = self.task(self, **self.params)
File "<ipython-input-1-c084194db610>", line 19, in say
raise Exception("I can't say anything right now")
Exception: I can't say anything right now
^^^^ END greet_and_count ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
现在我们打印了所有task。您还可以在输出的最右列看到严重性级别。
编程方式
我们已经暗示了如何处理结果对象，但让我们对其进行详细说明。首先，task组将返回AggregatedResult。该对象是一个类似dict的对象，可用于遍历或直接访问host：
result
AggregatedResult (greet_and_count): {'host1.cmh': MultiResult: [Result: "greet_and_count", Result: "Greeting is the polite thing to do", Result: "Counting beans", Result: "We should say bye too"], 'host2.cmh': MultiResult: [Result: "greet_and_count", Result: "Greeting is the polite thing to do"]}
result.keys()
dict_keys（['host1.cmh'，'host2.cmh']）
result["host1.cmh"]
MultiResult: [Result: "greet_and_count", Result: "Greeting is the polite thing to do", Result: "Counting beans", Result: "We should say bye too"]
您可能已经注意到，在AggregatedResult的每个键中都有一个MultiResult对象。该对象是类似列表的对象，可用于迭代或访问所需的任何Result：
result["host1.cmh"][0]
结果：“ greet_and_count”
双方MultiResult并Result应明确指出，如果有系统中的一些错误或更改：
print("changed: ", result["host1.cmh"].changed)
print("failed: ", result["host1.cmh"].failed)
changed: False failed: False
print("changed: ", result["host2.cmh"][0].changed)
print("failed: ", result["host2.cmh"][0].failed)
changed: False failed: True
