Ceph » rgw

Ceph supports conditional writing since 2014: https://tracker.ceph.com/issues/8562
However it doesn't work with the following cases:

• a bucket has versioning enabled
• it's a multipart upload

Current behavior¶

S3 API returns 201 even though the If-None-Match: * header was submitted to a bucket with the versioning enabled or during the multipart upload.

Simple bucket¶

This example works fine

$ curl -XPUT https://my-ceph.local/condition_write/only_once --aws-sigv4 aws:amz:default:s3 -u XX:XX -H "If-None-Match: *" -v -d"This is the first write" 2>&1 | egrep -i 'HTTP|etag|Modified'
* ALPN: curl offers h2,http/1.1
* using HTTP/1.x
> PUT /condition_write/only_once HTTP/1.1
< HTTP/1.1 200 OK
< ETag: "dcc31a80288e0758b0c522eaaa0b5bec" 
$ curl -XPUT https://my-ceph.local/condition_write/only_once --aws-sigv4 aws:amz:default:s3 -u XX:XX -H "If-None-Match: *" -v -d"This is the first write" 2>&1 | egrep -i 'HTTP|etag|Modified'
* ALPN: curl offers h2,http/1.1
* using HTTP/1.x
> PUT /condition_write/only_once HTTP/1.1
< HTTP/1.1 412 Precondition Failed

Bucket with versioning enabled¶

$ aws --region default --endpoint-url https://my-ceph.local s3api put-bucket-versioning --bucket condition_write --versioning-configuration Status=Enabled
$ curl -XPUT https://my-ceph.local/condition_write/only_once --aws-sigv4 aws:amz:default:s3 -u XX:XX -H "If-None-Match: *" -v -d"This is the first write" 2>&1 | egrep -i 'HTTP|etag|Modified'
* ALPN: curl offers h2,http/1.1
* using HTTP/1.x
> PUT /condition_write/only_once HTTP/1.1
< HTTP/1.1 200 OK
< ETag: "dcc31a80288e0758b0c522eaaa0b5bec" 
$ curl -XPUT https://my-ceph.local/condition_write/only_once --aws-sigv4 aws:amz:default:s3 -u XX:XX -H "If-None-Match: *" -v -d"This is the first write" 2>&1 | egrep -i 'HTTP|etag|Modified'
* ALPN: curl offers h2,http/1.1
* using HTTP/1.x
> PUT /condition_write/only_once HTTP/1.1
< HTTP/1.1 200 OK
< ETag: "dcc31a80288e0758b0c522eaaa0b5bec" 

Multipart upload¶

Create an initial key and test the second conditional write with the If-None-Match: *

$ curl -XPUT https://my-ceph.local/condition_write/only_once --aws-sigv4 aws:amz:default:s3 -u XX:XX -H "If-None-Match: *" -v -d"This is the first write" 2>&1 | egrep -i 'HTTP|etag|Modified'
* ALPN: curl offers h2,http/1.1
* using HTTP/1.x
> PUT /condition_write/only_once HTTP/1.1
< HTTP/1.1 200 OK
< ETag: "dcc31a80288e0758b0c522eaaa0b5bec" 
$ curl -XPUT https://my-ceph.local/condition_write/only_once --aws-sigv4 aws:amz:default:s3 -u XX:XX -H "If-None-Match: *" -v -d"This is the first write" 2>&1 | egrep -i 'HTTP|etag|Modified'
* ALPN: curl offers h2,http/1.1
* using HTTP/1.x
> PUT /condition_write/only_once HTTP/1.1
< HTTP/1.1 412 Precondition Failed

Run multipart upload against this key:

$ curl -s -XPOST https://my-ceph.local/condition_write/only_once?uploads -H "If-None-Match: *" --aws-sigv4 aws:amz:default:s3 -u XX:XX
<?xml version="1.0" encoding="UTF-8"?><InitiateMultipartUploadResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Tenant>481c6f7874024488a2ab2197e5bb1931</Tenant><Bucket>condition_write</Bucket><Key>only_once</Key><UploadId>2~QcmAkzqsyVF1un_uiLA-Ste89T_ExaN</UploadId></InitiateMultipartUploadResult>
$ curl -XPUT "https://my-ceph.local/condition_write/only_once?partNumber=1&uploadId=2~QcmAkzqsyVF1un_uiLA-Ste89T_ExaN" -H "If-None-Match: *" --aws-sigv4 aws:amz:default:s3 -u XX:XX -d"This is the multipart write" -v
...
< HTTP/1.1 200 OK
< Content-Length: 0
< ETag: "e4683000ff181d33580b4039304880da" 
...
$ curl -XPOST "https://my-ceph.local/condition_write/only_once?uploadId=2~QcmAkzqsyVF1un_uiLA-Ste89T_ExaN" -H "If-None-Match: *" -H "Content-Type: application/xml" --aws-sigv4 aws:amz:default:s3 -u XX:XX -d"<CompleteMultipartUpload><Part><PartNumber>1</PartNumber><ETag>e4683000ff181d33580b4039304880da</ETag></Part></CompleteMultipartUpload>" 
<?xml version="1.0" encoding="UTF-8"?><CompleteMultipartUploadResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Location>my-ceph.local/481c6f7874024488a2ab2197e5bb1931:condition_write/only_once</Location><Tenant>481c6f7874024488a2ab2197e5bb1931</Tenant><Bucket>condition_write</Bucket><Key>only_once</Key><ETag></ETag></CompleteMultipartUploadResult>
$ curl "https://my-ceph.local/condition_write/only_once" --aws-sigv4 aws:amz:default:s3 -u XX:XX 
This is the multipart write

As you see, the object was rewritten with the multipart upload content: This is the multipart write

Expected behavior¶

All update requests with the If-None-Match: * header must fail with the 412 response code.