How can I get Spot InstanceID from a Spot Instance Request?

Question

I'm using aws-go-sdk to create and manage spot instances. Every request I send in order to create a new Spot Instance Request is performed with RequestSpotInstances. I'm trying to get the Instance ID of the instance that was created for my last request, I saw that in the response object RequestSpotInstancesOutput there is a parameter for each instance that was created, but it does not include the instance id, in fact, the InstanceID is not being filled in the RequestSpotInstanceOutput, (returned from RequestSpotInstances call), I tried to use CreateTags in order to create a tag for each instance with the request id, but it didn't work. seen here: TagSpecifications with requestSpotInstances UnexpectedParameter with aws-sdk

param := &ec2.RequestSpotInstancesInput{    // Initializing the request params
    SpotPrice:     aws.String(ctx.Price),
    InstanceCount: aws.Int64(count),
    LaunchSpecification: &ec2.RequestSpotLaunchSpecification{
        ImageId:          aws.String(ctx.AWSImageID),
        InstanceType:     aws.String(ctx.InstanceType),
        KeyName:          aws.String(ctx.Key),
        UserData:         aws.String(""),
        SecurityGroupIds: aws.StringSlice(secgroup),
    },
    Type: aws.String("one-time"),
}

reqSliceCreateTagsInput := make([]string, 1)

resp, err := client.RequestSpotInstances(param)
if err != nil || resp == nil {
    log.Println(err.Error())
    log.Fatalf("pkg/aws: CreateSpotInstance resp is nil")
}
reqSliceCreateTagsInput[0] = *resp.SpotInstanceRequests[0].SpotInstanceRequestId
createTagsInput := &ec2.CreateTagsInput{
    Resources: aws.StringSlice(reqSliceCreateTagsInput),
    Tags: []*ec2.Tag{
        {
            Key:   aws.String("instance"),
            Value: aws.String(name + "-" + index),
        },
    },
}

time.Sleep(time.Second * 15)

_, err = client.CreateTags(createTagsInput)
if err != nil {
    slog.Logf(0, err.Error())
}

Is there any way to just receive the instance id by the request id only?

Answer 1

I think that it can take some time for a Spot Instance request to be fulfilled.

I would recommend you call describe_spot_instance_requests() until the Status of all instances is fulfilled (wait a little bit between each call).

I can't see a field that indicates that the whole request has been fulfilled, so you might need to compare the number of instances returned against the quantity that you requested.