Description
Acknowledgements
- I have searched (https://github.com/aws/aws-sdk/issues?q=is%3Aissue) for past instances of this issue
- I have verified all of my SDK modules are up-to-date (you can perform a bulk update with
go get -u github.com/aws/aws-sdk-go-v2/...)
Related to this but appears to be enabled by default now: #1606
Describe the bug
When calling S3 GetObject and using the IfNoneMatch (for ETag caching) the SDK logs a warn message:
SDK 2025/03/02 02:10:31 WARN Response has no supported checksum. Not validating response payload.
If you remove the IfNoneMatch and the object is actually fetched, the WARN log is not printed since the checksum validation is performed properly.
Regression Issue
- Select this option if this issue appears to be a regression.
Expected Behavior
The log should not be printed in cases where the object is not actually fetched.
WARN Response has no supported checksum. Not validating response payload.
Current Behavior
Prints the log when an object is not fetched due to IfNoneMatch (Not Modified). I haven't tested other ways to prevent the actual object fetch, but I suspect the same issue occurs with those.
WARN Response has no supported checksum. Not validating response payload.
Reproduction Steps
Here's a simple program to demonstrate:
package main
import (
"context"
"flag"
"fmt"
"log"
"os"
"github.com/aws/aws-sdk-go-v2/config"
"github.com/aws/aws-sdk-go-v2/service/s3"
)
func main() {
bucket := flag.String("bucket", "", "S3 bucket")
key := flag.String("key", "", "S3 key")
region := flag.String("region", os.Getenv("AWS_REGION"), "AWS Regon")
etag := flag.String("etag", "", "ETag")
flag.Parse()
ctx := context.Background()
cfg, err := config.LoadDefaultConfig(ctx, config.WithRegion(*region))
if err != nil {
log.Fatalf("failed to load AWS config %s", err)
}
s3Client := s3.NewFromConfig(cfg)
getObjInput := &s3.GetObjectInput{
Bucket: bucket,
Key: key,
}
if *etag != "" {
getObjInput.IfNoneMatch = etag
}
out, err := s3Client.GetObject(ctx, getObjInput)
if err != nil {
log.Fatalf("GetObject error %s", err)
}
fmt.Println(string(*out.ETag))
}
> go run main.go --bucket <any-bucket> --key <any-key>
"b6a75ac7399fa1cae64703727df347e8"
> go run main.go --bucket <any-bucket> --key <any-key> --etag b6a75ac7399fa1cae64703727df347e8
SDK 2025/03/02 02:10:31 WARN Response has no supported checksum. Not validating response payload.
2025/03/02 02:10:31 GetObject error operation error S3: GetObject, https response error StatusCode: 304, RequestID: DQSFW41K4QJ9124E, HostID: eernRlMJrXAXxwWuJfuB2CPwGU0SY/iTT20RjIMYpueu7pKDFy4KxWpSG23vTscN6Bn7cbhqo8E=, api error NotModified: Not Modified
Possible Solution
No response
Additional Information/Context
I can work around with this, but it's annoying to have to do this:
s3Client := s3.NewFromConfig(cfg, func(o *s3.Options) {
o.DisableLogOutputChecksumValidationSkipped = true
})
AWS Go SDK V2 Module Versions Used
github.com/aws/aws-sdk-go-v2 v1.36.2
github.com/aws/aws-sdk-go-v2/config v1.29.7
github.com/aws/aws-sdk-go-v2/service/s3 v1.77.1
github.com/aws/smithy-go v1.22.2
Compiler and Version used
go version go1.23.6 linux/amd64
Operating System and version
AL2 5.10.234-205.895.amzn2int.x86_64