aws ec2 describe instances output is not getting filtered

[lesh3000]

Describe the bug

I am using bash and calling:
aws ec2 describe-instances --region eu-central-1 --filters "Name=tag-key,Values=Name" --query "Reservations[].Instances[].Placement[*]"

However te result is empy.
If I do aws ec2 describe-instances --region eu-central-1 --filters "Name=tag-key,Values=Name" --query "Reservations[].Instances[].PrivateDnsName") it works as it should

Expected Behavior

List of placement objects

Current Behavior

Non

Reproduction Steps

aws ec2 describe-instances --region eu-central-1 --filters "Name=tag-key,Values=Name" --query "Reservations[].Instances[].Placement[*]"

Possible Solution

No response

Additional Information/Context

No response

CLI version used

aws-cli/1.18.147 Python/2.7.18 Linux/5.10.144-127.601.amzn2.x86_64 botocore/1.18.6

Environment details (OS name and version, etc.)

run on EC2 instance via console

[tim-finnigan]

Hi @lesh3000 thanks for reaching out. Here is the ec2 describe-instances documentation for reference: https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-instances.html

I think the snippet you're looking for is something like:

aws ec2 describe-instances --region eu-central-1 --filter Name=tag:Name,Values=<your_value_here> --query "Reservations[].Instances[].Placement"

Does that accomplish what you're trying to do? Please let us know.

[lesh3000]

Hi,
Thank you for your prompt reply.
It seems working if I call it this way: --query "Reservations[].Instances[].Placement[].AvailibilityZone[]"
I need to get AZ only.
The docs show mostly [*] usage in the end of the json property, where can I read about [] vs [*] vs none in the end?
Appreciate your help

[tim-finnigan]

Thanks @lesh3000 for following up. You can read more about client-side filtering with the AWS CLI here: https://docs.aws.amazon.com/cli/latest/userguide/cli-usage-filter.html#cli-usage-filter-client-side.

Also since this was a guidance-related question, I'm going to convert it to a GitHub discussion per our issue triage process. Please let us know if you had any additional questions or feedback.