AWS S3 Path having a fixed string in the middle - amazon-web-services

I was wondering if there is any difference between the below two paths. The first path has a fixed string in between. Will it have any kind of performance impact? S3 documentation mentions that they allow 3,500 PUT/COPY/POST/DELETE or 5,500 GET/HEAD requests per second per prefix in a bucket. And since both path below have a random prefix therefore we should be fine.
random_uuid/<some_fixed_string>/random_uuid
vs
random_uuid/random_uuid
Any pointers or help will be appreciated

S3 has a flat hierarchy and there are actually no folders. The names:
random_uuid/<some_fixed_string>/random_uuid
random_uuid/random_uuid
are both keys and the folder-subfolder hierarchy is imposed by the client. In S3 the items are simply stored with a key name and the '/' doesn't mean anything. Therefore they should be fully equivalent.

Related

Efficient way to find and delete s3 objects with extension

I have a bucket in S3 for which i want to delete all objects with a particular extension.
The easiest solution is to list all keys and checks if it ends with extension and delete it, but this solution is very costly. Can anyone suggest any efficient to achieve this?
Look at S3 Inventory report, if you do not need up-to-the minute accuracy.
Alternatively, you might have to create an index of your S3 objects in DynamoDB or elsewhere so that you can easily find objects with a given suffix. Or even consider restructuring your keys so that they begin with the file extension, then you can list a prefix such as csv/ (obviously this might have negative consequences elsewhere in your application so is not necessarily a good solution).
Note that the price of listing objects in S3 Standard is $0.005 per 1,000 requests and each of those requests will return up to 1,000 S3 keys. I'm not sure how many keys you would be listing but that's $0.005 per million objects.

What does prefix mean in S3

the docs says,
For example, your application can achieve at least 3,500 PUT/COPY/POST/DELETE and 5,500 GET/HEAD requests per second per prefix in a bucket. There are no limits to the number of prefixes in a bucket. You can increase your read or write performance by parallelizing reads. For example, if you create 10 prefixes in an Amazon S3 bucket to parallelize reads, you could scale your read performance to 55,000 read requests per second.
But, it doesn't clearly mentions the concept of prefixes.
For eg,
Lets say I have 3 files and their corresponding keys are:
a/a1.txt
b/b1.txt
2.txt
As per my understanding, there is no concept of folders in S3. So, S3 will create something like this on my bucket.
|- a/
|- a1.txt
|- 2.txt
|- b/
|- b1.txt
I did came across this blog but it made things more confusing for me.
My questions:-
Does every Object created in S3 that ends with '/' is a prefix?
In other words, Does every folder that we see in the S3 web console is a prefix?
Although S3 is theoretically a flat store, many of its operations have special handling for prefixes with a set delimiter, usually /. For instance this help page discusses how the "folders" on the S3 console web interface are built by looking at the prefixes you've used.
An important point to remember here is that these folders are not objects themselves, so in your example, there is no key of a or b stored in the bucket.
If you create a bucket and immediately add an object with a key of a/b/c/d/e.txt then:
the bucket will contain exactly one object, with key a/b/c/d/e.txt
some APIs and UIs will infer a prefix for that key of a/b/c/d, as a way of grouping related keys

Is there anything to be gained by using 'folders' in an s3 bucket?

I am moving a largish number of jpgs (several hundred thousand) from a static filesystem to amazon s3.
On the old filesytem, I grouped files into subfolders to keep the total number of files / folder manageable.
For example, a file
4aca29c7c0a76c1cbaad40b2693e6bef.jpg
would be saved to:
/4a/ca/29/4aca29c7c0a76c1cbaad40b2693e6bef.jpg
From what I understand, s3 doesn't respect hierarchial namespaces. So if I were to use 'folders' on s3, the object, including the /'s, would really just be in a flat namesapce.
Still, according to the docs, amazon recommends mimicking a structured filesytem when working with s3.
So I am wondering: Is there anything to be gained using the above folder structure to organize files on s3? Or in this case am I better off just adding the files to s3 without any kind of 'folder' structure.
Performance is not impacted by the use (or non-use) of folders.
Some systems can use folders for easier navigation of the files. For example, Amazon Athena can scan specific sub-directories when querying data rather than having to read every file.
If your bucket is being used for one specific purpose, there is no reason to use folders. However, if it contains different types of data, then you might consider at least a top-level set of folders to keep data separated.
Another potential reason for using folders is for security. A bucket policy can grant access to buckets based upon a prefix (which is a folder name). However, this is likely not relevant for your use-case.
Using "folders" has no performance impact on S3, either way. It doesn't make it faster, and it doesn't make it slower.
The value of delimiting your object keys with / is in organization, both machine-friendly and human-friendly.
If you're trolling through a bucket in the console, troubleshooting, those meaningless noise-filled keys are a hassle to paginate through, only a few dozen at a time.
The console automatically groups objects into imaginary folders based on the / delimiters, so you can find your object to inspect it (check headers, metadata, etc.) is much easier if you can just click on 4a then ca then 29.
The S3 ListObjects APIs support requesting all the objects with a certain key prefix, but they also support finding all the common prefixes before the next delimiter, so you can send API requests to list prefix 4a/ca/ with delimiter / and it will only return the "folders" one level deep, which it refers to as "common prefixes."
This is less meaningful if your object keys are fully opaque and convey nothing more about the objects, as opposed to using key prefixes like images/ and thumbnails/ and videos/.
Having been an admin and working with S3 for a number of years, and having worked with buckets with key naming schemes designed by different teams, I would definitely recommend using some / delimiters for organization purposes. The buckets without them become more of a hassle to navigate over time.
Note that the console does allow you to "create folders," but this is more of the illusion -- there is no need to actually do this, unless you're loading a bucket manually. When you create a folder in the console, it just creates an empty object with a / at the end.

Is there a way to query S3 object key names for the latest per prefix?

In an S3 bucket, I have thousands and thousands of files stored with names having a structure that comes down to prefix and number:
A-0001
A-0002
A-0003
B-0001
B-0002
C-0001
C-0002
C-0003
C-0004
C-0005
New objects for a given prefix should come in with varying frequency, but might not. Older objects may disappear.
Is there a way to efficiently query S3 for the highest number of every prefix, i.e. without listing the entire bucket? The result I want is:
A-0003
B-0002
C-0005
The S3 API itself does not seem to offer anything usable for that. However, perhaps another service, like Athena, could do it? So far I have only found it capable of searching within objects, but all I care about are their key names. If it can report on the contents of objects in the bucket, can't it on the bucket itself?
I would be okay with the latest modification date per prefix, but I want to avoid having to switch to a versioned bucket with just the prefixes as names to achieve that.
I think this is what you are looking for:
variable name is $path and you can regexp to get the pattern you are querying...
WHERE regexp_extract(sp."$path", '[^/]+$') like concat('%',cast(current_date - interval '1' day as varchar),'.csv')
The S3 API itself does not seem to offer anything usable for that.
However, perhaps another service, like Athena, could do it?
Yes at the moment, there is not direct way of doing it only with AWS S3. Even with Athena, it will go through the files to query their content but it will be easier using standard SQL support with Athena and would be faster since the queries runs in parallel.
So far I have only found it capable of searching within objects, but
all I care about are their key names.
Both Athena and S3 Select is to query by content not keys.
The best approach I can recommend is to use AWS DynamoDB to keep the metadata of the files, including file names for faster querying.

Top level solution to rename AWS bucket item's folder names?

I've inherited a project at work. Its essentially a niche content repository, and we use S3 to store the content. The project was severely outdated, and I'm in the process of a thorough update.
For some unknown and undocumented reason, the content is stored in an AWS S3 bucket with the pattern web_cl_000000$DB_ID$CONTENT_NAME So, one particular folder can be named web_cl_0000003458zyxwv. This makes no sense, and requires a bit of transformation logic to construct a URL to serve up the content!
I can write a Python script using the boto3 library to do an item-by-item rename, but would like to know if there's a faster way to do so. There are approximately 4M items in that bucket, which will take quite a long time.
That isn't possible, because the folders are an illusion derived from the strings between / delimiters in the object keys.
Amazon S3 has a flat structure with no hierarchy like you would see in a typical file system. However, for the sake of organizational simplicity, the Amazon S3 console supports the folder concept as a means of grouping objects. Amazon S3 does this by using key name prefixes for objects. (emphasis added)
http://docs.aws.amazon.com/AmazonS3/latest/UG/FolderOperations.html
The console contributes to the illusion by allowing you to "create" a folder, but all that actually does is create a 0-byte object with / as its last character, which the console will display as a folder whether there are other objects with that prefix or not, making it easier to upload objects manually with some organization.
But any tool or technique that allows renaming folders in S3 will in fact be making a copy of each object with the modified name, then deleting the old object, because S3 does not actually support rename or move, either -- objects in S3, including their key and metadata, are actually immutable. Any "change" is handled at the API level with a copy/overwrite or copy-then-delete.
Worth noting, S3 should be able to easily sustain 100 such requests per second, so with asynchronous requests or multi-threaded code, or even several processes each handling a shard of the keyspace, you should be able to do the whole thing in a few hours.
Note also that the less sorted (more random) the new keys are in the requests, the harder you can push S3 during a mass-write operation like this. Sending the requests so that the new keys are in lexical order will be the most likely scenario in which you might see 503 Slow Down errors... in which case, you just back off and retry... but if the new keys are not ordered, S3 can more easily accommodate a large number of requests.