About *MaxResults field in DescribeXXXInput

[sdminonne]

Some requests (for example *ec2.DescribeSubnetsInput or *ec2.DescribeVpcsInput) contain a MaxResults filed (*int32). I couldn't find documentation about this field. Is there some best-practice around the value to set?

[RanVaknin]

Hi @sdminonne ,
Since some describe* or list* operations may return a large subset of results, the API allows you to set a limit so you can paginate through the entire list of results. In order to paginate through the results you will need to implement a paginator function with logic to set the limit and call next token (also a parameter in the request)
So while this may be a use case for someone that interacts with the API directly, consumers of the SDK have access to the built-in paginators generated for those supported operations.
So for example ec2.DescribeSubnets:
package main

import (
"context"
"fmt"
"github.com/aws/aws-sdk-go-v2/config"
"github.com/aws/aws-sdk-go-v2/service/ec2"
)

func main() {
cfg, err := config.LoadDefaultConfig(context.TODO())
if err != nil {
panic(err)
}

client := ec2.NewFromConfig(cfg)

paginator := ec2.NewDescribeSubnetsPaginator(client, &ec2.DescribeSubnetsInput{}, func(o *ec2.DescribeSubnetsPaginatorOptions) {
	o.Limit = 5 // instead of using maxResults, we use the Limit argument to interact with the built in paginator.
})

for paginator.HasMorePages() {
	page, err := paginator.NextPage(context.TODO())
	if err != nil {
		panic(err)
	}

	for _, subnet := range page.Subnets {
		fmt.Println("Subnet ID:", *subnet.SubnetId)
	}
}

}
You can read more about pagination in the SDK here.
I hope this helps.
Thanks,
Ran~
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