CODEWITHSUNDEEP
python-3.xlist
bassgnome
bassgnome

Reputation: 61

Why do I get an error when converting a list to a string?

I am relatively new to Python and am trying to take the output of the command 

aws ec2 describe-images --filters Name=name,Values=Nessus*BYOL*

and get the value of ImageId. But when I try, I get the following error:

TypeError: 'int' object is not subscriptable

I've tried to convert it to a string, but I don't know if that's the correct way of doing this. I've also tried to regex it, but that didn't seem to work out neither.

At the end of the day, I need to assign the value of ImageId to a variable for later use.

Here's my code:

def queries():
    describe_images = subprocess.call("aws ec2 describe-images --filters Name=name,Values=Nessus*BYOL*")
    str(print(describe_images["ImageId"]))

Here's the output that you get when you run that command:

{
    "Images": [
        {
            "Architecture": "x86_64",
            "CreationDate": "2019-06-04T11:50:36.000Z",
            "ImageId": "ami-0d700172aa0395099",
            "ImageLocation": "aws-marketplace/Nessus 8.4.0 (master-193 1558031440.58) BYOL-8e783acf-0dfb-44dc-b080-415aad141bb2-ami-03eadadcd69ef2dbc.4",
            "ImageType": "machine",
            "Public": true,
            "ProductCodes": [
                {
                    "ProductCodeId": "8fn69npzmbzcs4blc4583jd0y",
                    "ProductCodeType": "marketplace"
                }
            ],
            "State": "available",
            "BlockDeviceMappings": [
                {
                    "DeviceName": "/dev/xvda",
                    "Ebs": {
                        "DeleteOnTermination": false,
                        "SnapshotId": "snap-07020d6ea4da33df4",
                        "VolumeSize": 8,
                        "VolumeType": "gp2",
                        "Encrypted": false
                    }
                }
            ],
            "EnaSupport": false,
            "Hypervisor": "xen",
            "ImageOwnerAlias": "aws-marketplace",
            "Name": "Nessus 8.4.0 (master-193 1558031440.58) BYOL-8e783acf-0dfb-44dc-b080-415aad141bb2-ami-03eadadcd69ef2dbc.4",
            "RootDeviceName": "/dev/xvda",
            "RootDeviceType": "ebs",
            "VirtualizationType": "hvm"
        }
    ]
}

Upvotes: 1

Views: 42

Answers (1)

Selcuk
Selcuk

Reputation: 59444

The subprocess.call method will return the returncode, not the command output. From the documentation:

subprocess.call(args, *, stdin=None, stdout=None, stderr=None, shell=False, cwd=None, timeout=None)

Run the command described by args. Wait for command to complete, then return the returncode attribute.

Perhaps you wanted to use .check_output():

Run command with arguments and return its output.

Also note that the output will be a string. You should use json.loads() to convert it to a Python dictionary first.

Upvotes: 1

Related Questions