Print all matching JSON dictionaries in Python

Question

I am currently using the AWS Boto3 to try to get a list of all of my current running EC2 instances. I am at the point where I am able to use describe_instances to list all of my instances, but I am trying to figure out how to pull out all of the instance ID's so I can print them AND use them for another part of the script. Ultimately, I have one script that spins up all of the instance, next I want one that tears them all down.

JSON Tree bellow.

To select a specifc one, I have to do this,

instance_id = response['Reservations'][0]['Instances'][0]['InstanceId']

But I want to be able to select all instances, regardless of how many instances I have, so trying to do [0][1] etc isn't feasable, so not sure how I would go about saying I want every InstanceId that is in the command.

{
    u'Reservations': [
        {
            u'Groups': [

            ],
            u'Instances': [
                {
                    u'AmiLaunchIndex': 0,
                    u'Architecture': 'i386',
                    u'EbsOptimized': False,
                    u'Hypervisor': 'xen',
                    u'InstanceId': 'i-6fb4ad61',
                }
            ],
            u'OwnerId': '',
            u'ReservationId': ''
        },
        {
            u'Groups': [

            ],
            u'Instances': [
                {
                    u'AmiLaunchIndex': 0,
                    u'Architecture': 'i386',
                    u'EbsOptimized': False,
                    u'Hypervisor': 'xen',
                    u'InstanceId': 'i-afe3faa1',
                }
            ],
            u'OwnerId': '',
            u'ReservationId': ''
        }
    ],
    'ResponseMetadata': {
        'HTTPHeaders': {
            'content-type': 'text/xml;charset=UTF-8',
            'date': 'Thu, 25Aug201623: 44: 09GMT',
            'server': 'AmazonEC2',
            'transfer-encoding': 'chunked',
            'vary': 'Accept-Encoding'
        },
        'HTTPStatusCode': 200,
        'RequestId': ''
    }
}

Here is the command I am using to get the instance ID.

launch_instance = ec2.create_instances(ImageId="xxxxxx", MinCount=1, MaxCount=1,SecurityGroupIds=["sg-xxxxxxx"],InstanceType='m3.medium', SubnetId='subnet-xxxxx')


response = ec2client.describe_instances(
    InstanceIds=[
        launch_instance[0].id],
)

instance_id = response['Reservations'][0]['Instances'][0]['InstanceId']

print instance_id

output is i-6fb4ad61

L Kehiky · Accepted Answer · 2016-08-26 16:53:33Z

2

Try this

instance_ids = []
for reservations in response['Reservations']:
    for instance in reservations['Instances']:
        instance_ids.append(instance['InstanceId'])

edited Aug 26, 2016 at 16:53

answered Aug 26, 2016 at 16:40

L Kehiky

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2 Comments

Mallachar Over a year ago

I get this in ipython 'AttributeError: 'dict' object has no attribute 'append''

L Kehiky Over a year ago

@Mallachar sorry, I've made a typo :( I've updated my answer

Moinuddin Quadri · Accepted Answer · 2016-08-26 17:04:48Z

2

You may achieve is via:

>>> instance_ids = [instance['InstanceId'] for reservations in response['Reservations'] for instance in reservations['Instances']]
>>> instance_ids
['i-6fb4ad61', 'i-afe3faa1']

where your JSON structure is saved as response

edited Aug 26, 2016 at 17:04

answered Aug 26, 2016 at 16:39

Moinuddin Quadri

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3 Comments

Mallachar Over a year ago

I get TypeError: string indices must be integers

Mallachar Over a year ago

Actually, for some reason it prints the same one twice for me In [25]: print instance_ids ['i-6fb4ad61', 'i-6fb4ad61']

Moinuddin Quadri Over a year ago

Sorry! Yes there was one issue with the code. Fixed it. :)

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