resolve-ec2-id

Links

• GitLab
• GitHub
• PyPI

Introduction

This is a simple command-line tool which looks up the EC2 instance ID given an instance name:

$ resolve-ec2-id my-named-instance
i-1234567890abcdef0

Currently this tool only works with default credentials. Consider configuring them with environment variables or using a program like aws-vault.

Alternatives

This package is perhaps not so useful because very similar functionality can be accomplished with AWS CLI as follows:

aws ec2 describe-instances --filters 'Name=tag:Name,Values=my-named-instance' --query 'Reservations[*].Instances[*].{Instance:InstanceId}' --output text

However, this tool has slightly better error-handling; the above AWS CLI command will not generate an error in the case that no instance is found.

Installation

In order to install in a clean and isolated Python environment, it is recommended to use pipx:

pipx install resolve-ec2-id

Examples

Assuming you are using the Bash shell, to start an instance if you know the name but not the ID:

$ aws ec2 start-instances --output=yaml --instance-ids="$(resolve-ec2-id my-named-instance)"
StartingInstances:
- CurrentState:
    Code: 0
    Name: pending
  InstanceId: i-1234567890abcdef0
  PreviousState:
    Code: 80
    Name: stopped

This can also be used from within Python:

from resolve_ec2_id import resolve_ec2_id

ec2_id = resolve_ec2_id('my-named-instance')

Requirements

Beyond the base dependencies which install automatically, this requires either AWS CLI or boto3. (I did not make boto3 a dependency because it isn't needed if AWS CLI is already installed.)