Retrieving command invocation in AWS SSM

Question

I am trying to send command to a running ubuntu ec2 instance. I have configured the appropriate role and I have an ssm agent running on the ec2 instance. Using the boto3 SDK I am able to use the client.send_command() function to successfully send a shell command and was subsequently able to get the command Id. Now the challenge is polling for the result. I am trying to use the client.get_command_invocation() function but keep getting a InvocationDoesNotExist error. I am confident that I am using the correct command ID and instance ID because I have tested these using the AWS CLI as in aws ssm list-command-invocations --command-id #### --instance-id i-##### and this worked. Here is a snippet of my code:

`ssm_client = boto3.client('ssm')
target_id = "i-####"
response = ssm_client.send_command(
            InstanceIds=[
                target_id 
                    ],
            DocumentName="AWS-RunShellScript",
            Comment="Code to run" ,
            Parameters={
                    "commands": ["ls -l"]
                        }
            )
cmd_id= response['Command']['CommandId']
response = ssm_client.get_command_invocation(CommandId=cmd_id, 
InstanceId=target_id)
print(response)`

Here is the returned error: botocore.errorfactory.InvocationDoesNotExist: An error occurred (InvocationDoesNotExist) when calling the GetCommandInvocation operation

Thanks in advance.

Answer 1

Just add these 2 line.

import time
time.sleep(2)

Then It'll work properly generally it take only 0.65sec but it's better to give 2 sec. To make it better you can add some cool stuffs like some print statement in for loop and sleep inside it something like that.

Answer 2

I had the same issue, I fixed it by adding a time.sleep() call before calling get_command_invocation(). A short delay should be enough.