7 Mar
2020
7 Mar
'20
7:05 a.m.
HI Romit,
first of all thanks for your reply,
The Code that I have attached above fetches blobs in the batches of 1000
because 1000 is what S3 client can fetch at a time.
* The total no of objects in bucket are around 3000 files and total 2.8 GB
in size
* To rule out the possibility of error in my code, I tried various
approaches in both java and as well as python (using boto) and by
increasing client timeout, retry limit, but it's the same exception
everywhere and I tried setting batch sizes to 10, 50, 100, 200,500 and 1000
but every other time listing fails after N number of iterations, I have
pasted the code snippets of various approaches I have tried below
* I have increased the S3 gateway Pod count to rule out the possibility of
S3 gateway pod being bombaded
* I tried s3cmd recursive approach to get the file count of the bucket and
there also I see errors while listing
Please do let me know if there are any other ways I can check what's going
on at backend
Rajiv.Chodisetti@aakashonprem:~$ s3cmd ls -r s3://my-new-bucket/ --no-ssl
--host=${AWS_HOST} --host-bucket= s3://my-new-bucket > listing.txt
WARNING: Retrying failed request:
/?marker=test-training-akash/du/latest/11340612-0.png.json
WARNING: 500 (UnknownError)
WARNING: Waiting 3 sec...
WARNING: Retrying failed request:
/?marker=test-training-akash/du/latest/11340612-0.png.json
WARNING: 500 (UnknownError)
WARNING: Waiting 6 sec...
^CSee ya!
* Approach 1:*
for (Bucket bucket : s3.listBuckets()) {
System.out.println(" - " + bucket.getName() + " "
+ "(owner = " + bucket.getOwner()
+ " "
+ "(creationDate = " + bucket.getCreationDate());
ObjectListing objectListing = s3.listObjects(new
ListObjectsRequest()
.withBucketName(bucket.getName()));
do {
for (S3ObjectSummary objectSummary :
objectListing.getObjectSummaries()) {
System.out.println(" --- " + objectSummary.getKey()
+ " "
+ "(size = " + objectSummary.getSize() +
")" + " "
+ "(eTag = " + objectSummary.getETag() +
")");
}
objectListing =
s3.listNextBatchOfObjects(objectListing);
} while (objectListing.isTruncated());
}
* Approach 2:*
// where i is global variable to keep track of blobs listed so far
// Recursive code to list blobs in Batches of N
private void listDataset(Bucket bucket, AmazonS3 conn, String
nextMarker) {
try {
ListObjectsRequest request = new ListObjectsRequest();
request.setBucketName(bucket.getName());
request.setMaxKeys(200);
if (nextMarker != null && nextMarker.length() > 0) {
request.setMarker(nextMarker);
}
ObjectListing result;
result = conn.listObjects(request);
for (S3ObjectSummary objectSummary :
result.getObjectSummaries()) {
System.out.println(" - " + objectSummary.getKey() + "
" +
"(size = " + objectSummary.getSize() +
")");
i = i + 1;
}
System.out.println("Total Blobs Fetched So far: " + i);
if (result.getNextMarker() != null) {
System.out.println("Next Object Marker: " +
result.getNextMarker());
nextMarker = result.getNextMarker();
listDataset(bucket, conn, nextMarker);
}
} catch (Exception e) {
e.printStackTrace();
}
}
* Approach 3:*
done = False
marker = None
while not done:
if marker:
data = s3.list_objects(Bucket='my-new-bucket', MaxKeys=10,
Marker=marker)
else:
data = s3.list_objects(Bucket='my-new-bucket', MaxKeys=10)
for key in data['Contents']:
print(key)
if data['IsTruncated']:
marker = data['Contents'][-1]['Key']
else:
done = True
*Approach 4:*
paginator = s3.get_paginator('list_objects')
page_iterator = paginator.paginate(Bucket='my-new-bucket')
for page in page_iterator:
if "Contents" in page:
for key in page["Contents"]:
print(key)
On Sat, Mar 7, 2020 at 7:32 AM Romit Misra <romit.misra(a)flipkart.com> wrote:
Some pointers:-
1.What is the approx object count in the bucket...?
2. Use range list,( iterate 1000 objects at a time, and store the last
marker to move to the next list, also referred to as paginated listing)
3.Check your default timeouts, and optimize tune according to environment
4.Monitor the system metrics when listing is happening, ( CPU and memory)
5.Use a alternative client like s3cmd, or Boto rule out the anamoly if in
your code.
Thanks
Romit
On Sat, 7 Mar 2020, 02:34 rajiv chodisetti, <rajivchodisetti54(a)gmail.com>
wrote:
HI,
I have created an S3 bucket backed by CEPH and through java S3 client and
via S3 object gateway am listing all the files under the bucket and always
the listing is failing some times after listing 1k+ blobs or some times
after listing 2k+ blobs and am not able to figure out how to debug this
issue
This is the Exception am getting,
com.amazonaws.services.s3.model.AmazonS3Exception: null (Service: Amazon S3; Status Code:
500; Error Code: UnknownError; Request ID:
tx00000000000000000e7df-005e626049-1146-rook-ceph-store; S3 Extended Request ID:
1146-rook-ceph-store-rook-ceph-store), S3 Extended Request ID:
1146-rook-ceph-store-rook-ceph-store
at
com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleErrorResponse(AmazonHttpClient.java:1799)
I tried with Boto as well and it's the same error over there,
I have checked the s3 gateway pod logs but I couldn't find any relevant
logs over there, so, please let me know how do I debug this issue or
possible reasons for the same
I have attached the java code am using for reference.
Thanks & Regards,
Rajiv
UIPath
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