博托實例.__字典__ [ '標籤'] [ '名稱']輸出問題

Question

UPDATE：

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我做了什麼，是下面的建議，不過，我仍然得到一個KeyError異常： '名稱'在輸出中，即使輸出是正確的。

這是輸出：

us-west-1 EC2Connection: 
ec2.us-west-1.amazonaws.com 
Showing all of your current instances 
Proxy-44-1000-Enrollments 
Proxy-45-1000-Enrollments 
Proxy-48-1000-Enrollments 
Proxy-49-1000-Enrollments 
Proxy-59-1000-Enrollments 
Proxy-67-1000-Enrollments 

Traceback (most recent call last): File "/Users/xxxxx/xxxx/boto/instanceid.py", 
line 43, in <module> print "\t%s" % (instance.tags['Name']) if instance.state == 
'running' else instance.state KeyError: 'Name' 

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最初的問題：

我試圖從他們的 「名稱」 標籤沿傾倒出的實例ID的列表AWS使用boto。我在網上找到了一個可以附加到實例對象的方法，名爲__dict__，這似乎工作正常，但是，我只想在使用此方法時拉出「name」標記，但我一直收到錯誤「Key Error ： '名稱' 「

基本上，此代碼的工作：

# Creating connection object to EC2 
conn = boto.connect_ec2() 

regions = boto.ec2.regions() 

# the 5 element in the array is "us-west-1" and setting the object to connect 
us = regions[5] 
print us.name 
conn_us = us.connect() 
print conn_us 

filters = {'key-name' : 'misc-key'} 

all_inst = conn_us.get_all_instances(filters=filters) 

print "Showing all of your current instances" 
for res in all_inst: 
    # each reservation have a instance: 
    for instance in res.instances: 
     print "\t%s: \t%s" % (instance.id, instance.__dict__['tags']) 

輸出是hoky壽：

us-west-1 
EC2Connection:ec2.us-west-1.amazonaws.com 
Showing all of your current instances 
    i-xxxxxxxx:  {u'Name': u'Proxy-xx-1000-Enrollments'} 
    i-xxxxxxxx:  {u'Name': u'Proxy-xx-1000-Enrollments'} 
    i-xxxxxxxx:  {u'Name': u'Proxy-xx-1000-Enrollments'} 
    i-xxxxxxxx:  {u'Name': u'Proxy-xx-1000-Enrollments'} 
    i-xxxxxxxx:  {u'Name': u'Proxy-xx-1000-Enrollments'} 

當我做出改變的__dict__方法來 」拉「 出」名稱「，它工作（或似乎工作，但拋出錯誤：

下面是代碼的變化：

print "\t%s: \t%s" % (instance.id, instance.__dict__['tags']['Name']) 

這裏是輸出：

us-west-1 
EC2Connection:ec2.us-west-1.amazonaws.com 
Showing all of your current instances 
    i-xxxxxxxx:  Proxy-xx-1000-Enrollments 
    i-xxxxxxxx:  Proxy-xx-1000-Enrollments 
    i-xxxxxxxx:  Proxy-xx-1000-Enrollments 
    i-xxxxxxxx:  Proxy-xx-1000-Enrollments 
    i-xxxxxxxx:  Proxy-xx-1000-Enrollments 
    i-xxxxxxxx:  Proxy-xx-1000-Enrollments 

Traceback (most recent call last): 
    File "/Users/xxxxxx/xxx.xxx/boto/instanceid.py", line 43, in <module> 
    print "\t%s: \t%s" % (instance.id, instance.__dict__['tags']["Name"]) 
KeyError: 'Name' 

我喜歡這個輸出，WITHOUT錯誤 - 誰能告訴我，我做錯了什麼這裏？

謝謝

Answer 1

爲什麼不直接訪問tags屬性？通過__dict__前往不是很Python的：

instance.tags['Name'] 

你可能也想看看，因爲一些你從get_all_instances回來（預約對象實例的實例的狀態），可最近終止實例。你可以只運行情況報告的名稱和狀態，否則（注 - 這.STATE檢查只是一個想法，以顯示A if cond else B語法你仍然會對自己玩它。）：

instance.tags['Name'] if instance.state == 'running' else instance.state 

如果您只想避免KeyError並返回默認值，則可以使用dict.get()。

instance.tags.get('Name') 
# or with a default 
instance.tags.get('Name', '--') 

下面是從提及預約對象和實例狀態boto ec2 tutorial拉着Blurb的。

If you just want to get a list of all of your running instances, use the get_all_instances method of the connection object. Note that the list returned is actually a list of Reservation objects (which contain the Instances) and that the list may include recently terminated instances for a small period of time subsequent to their termination.