Boto3 s3 resource check if file exists

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. How to check if a particular file is present inside a particular directory in my S3? I use Boto3 and tried this code which doesn't work :.

Learn more. Asked 6 months ago. Active 6 months ago. Viewed times. Active Oldest Votes. Willie Cheng Willie Cheng 4, 6 6 gold badges 30 30 silver badges 50 50 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Cryptocurrency-Based Life Forms. Q2 Community Roadmap. Featured on Meta. Community and Moderator guidelines for escalating issues via new response….

Feedback on Q2 Community Roadmap. Triage needs to be fixed urgently, and users need to be notified upon….They provide a higher-level abstraction than the raw, low-level calls made by service clients. To use resources, you invoke the resource method of a Session and pass in a service name:. Every resource instance has a number of attributes and methods. These can conceptually be split up into identifiers, attributes, actions, references, sub-resources, and collections.

Each of these is described in further detail below and in the following section. Resources themselves can also be conceptually split into service resources like sqss3ec2etc and individual resources like sqs. Queue or s3. Service resources do not have identifiers or attributes. The two share the same components otherwise. An identifier is a unique value that is used to call actions on the resource.

Resources must have at least one identifier, except for the top-level service resources e. An identifier is set at instance creation-time, and failing to provide all necessary identifiers during instantiation will result in an exception. Examples of identifiers:. Identifiers also play a role in resource instance equality. For two instances of a resource to be considered equal, their identifiers must be equal:.

Only identifiers are taken into account for instance equality. Region, account ID and other data members are not considered. When using temporary credentials or multiple regions in your code please keep this in mind. Resources may also have attributes, which are lazy-loaded properties on the instance. They may be set at creation time from the response of an action on another resource, or they may be set when accessed or via an explicit call to the load or reload action.

Examples of attributes:. Attributes may incur a load action when first accessed. If latency is a concern, then manually calling load will allow you to control exactly when the load action and thus latency is invoked. The documentation for each resource explicitly lists its attributes. Additionally, attributes may be reloaded after an action has been performed on the resource.I have a piece of code that opens up a user uploaded.

Then it uploads each file into an AWS S3 bucket if the file size is different or if the file didn't exist at all before. I'm using the boto3 S3 client so there are two ways to ask if the object exists and get its metadata. Option 1: client. Option 2: client.

boto3 s3 resource check if file exists

The problem with client. Sane but odd. If the object does not exist, boto3 raises a botocore. ClientError which contains a response and in it you can look for exception. What I noticed was that if you use a try:except ClientError: approach to figure out if an object exists, you reset the client's connection pool in urllib3.

So after an exception has happened, any other operations on the client causes it to have to, internally, create a new HTTPS connection. That can cost time. I wrote and filed this issue on github. Before we begin, which do you think is fastest? But S3 isn't a normal database. Here's the script partially cleaned up but should be easy to run. So I wrote a loop that ran 1, times and I made sure the bucket was empty so that 1, times the result of the iteration is that it sees that the file doesn't exist and it has to do a client.

My home broadband can cause temporary spikes. Clearly, using client. But note! Ok upload it". So the times there include all the client.

So why did I measure both? The reason is that the approach of using try:except ClientError: followed by a client. Again, see the issue which demonstrates this in different words.

boto3 s3 resource check if file exists

So, I simply run the benchmark again. The first time, it uploaded all 1, uniquely named objects. So running it a second time, every time the answer is that the object exists, and its size hasn't changed, so it never triggers the client.

In this case, using client. Even on a home broadband connection. In other words, I don't think that difference is significant. The point of using client. Having to create a new HTTPS connection and adding it to the pool costs time, but what if we disregard that and compare the two functions "purely" on how long they take when the file does NOT exist?

Remember, the second measurement above was when every object exists. So we know it took 0. How long does it take to figure out that the object does not exist independent of any other op. That means we avoid the bug so the comparison is fair. The client. And it matters.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Get subdirectory info folder¶

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have a lambda function that creates a folder in S3 for a user if they don't have one, and then it will eventually be populated with mp3 files. For my test cases, I have to handle for if the file exists. For that, I am trying to use this:. I always get NoneType because it doesn't exist, but for testing purposes I have everything created already and I just want the success case to go through, so it does exist but I am not properly 'getting' the info.

The response is really long and formatted to one line automatically unfortunately, but there is a key inside the folder called u'Key': u'philips exmaple.

My first question is how can I access that key properly with my get method? My second question is, when I know I am getting the key properly and it returns NoneType meaning it hasnt been created yet how could I use that as a conditional statement that allows the function to continue? The problem is, if I get returned nothing I want this function to work properly. I tried with this syntax but I receive an error about looping.

So I need a loop I assume? Where and how should I start the loop with my current set up? Seems simple but I am very new to Python so it would be helpful! You can read more about the specifics of what is in the response file and how it is structured in the boto3 documentation. The response object is just a dictionary. The value for Key is nested within Contentsso to access Key in the response object you can use:. If multiple keys are returned by the request then you could alternatively just loop through the Contents objects and create a list of all the keys return like this:.

boto3 s3 resource check if file exists

Learn more. How to check if a particular file exists in a top level folder in s3, using lambda, boto3 and python 2. Asked 1 year, 5 months ago. Active 1 year, 5 months ago. Viewed 2k times. This question has two parts I guess but I will explain: The scenario: I have a lambda function that creates a folder in S3 for a user if they don't have one, and then it will eventually be populated with mp3 files. Thanks for your time. Philip Morgan. Philip Morgan Philip Morgan 23 7 7 bronze badges.

Active Oldest Votes. I appreciate the response, I thought about the problem and I realized it is pretty simple even if I do not know Python. I have a similar answer to yours in my edit but I need to handle for NoneType properly. I was wondering how I could set that loop up in my scenario.

Sorry if I am asking a bad question but I felt I needed to talk through the issue with someone. I will check your answer anyway. Your question isn't entirely clear. If you're just looking to determine if a key exists you should checkout this answer: Check if a Key Exists in a S3 Bucket. If you have more than that being returned you'll run into issues. Sign up or log in Sign up using Google.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. I tried with the example from the documentation and from tests but I had no luck. That is a currently unreleased feature. It will be available in the next minor version of boto3. Please check out the stable dos to only see features which have been pushed out in a release. I'm seeing the same thing on 1.

Python Tutorial: How To Check if a File or Directory Exists

Ah, that's it. Thanks very much. Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Sign up. New issue. Jump to bottom. Labels pending-release.

Copy link Quote reply. JordonPhillips added the pending-release label Aug 1, This comment has been minimized. Sign in to view. JordonPhillips closed this Aug 1, This operation aborts a multipart upload.

After a multipart upload is aborted, no additional parts can be uploaded using that upload ID. The storage consumed by any previously uploaded parts will be freed. However, if any part uploads are currently in progress, those part uploads might or might not succeed.

As a result, it might be necessary to abort a given multipart upload multiple times in order to completely free all storage consumed by all parts. To verify that all parts have been removed, so you don't get charged for the part storage, you should call the ListParts operation and ensure that the parts list is empty. The following operations are related to AbortMultipartUpload :. When using this API with an access point, you must direct requests to the access point hostname.

You first initiate the multipart upload and then upload all parts using the UploadPart operation. After successfully uploading all relevant parts of an upload, you call this operation to complete the upload.

Upon receiving this request, Amazon S3 concatenates all the parts in ascending order by part number to create a new object. In the Complete Multipart Upload request, you must provide the parts list. You must ensure that the parts list is complete.

boto3 s3 resource check if file exists

This operation concatenates the parts that you provide in the list. For each part in the list, you must provide the part number and the ETag value, returned after that part was uploaded. Processing of a Complete Multipart Upload request could take several minutes to complete.

While processing is in progress, Amazon S3 periodically sends white space characters to keep the connection from timing out.

Because a request could fail after the initial OK response has been sent, it is important that you check the response body to determine whether the request succeeded.

Note that if CompleteMultipartUpload fails, applications should be prepared to retry the failed requests. The following operations are related to DeleteBucketMetricsConfiguration :. If the object expiration is configured, this will contain the expiration date expiry-date and rule ID rule-id. The value of rule-id is URL encoded. Entity tag that identifies the newly created object's data.

Objects with different object data will have different entity tags. The entity tag is an opaque string. The entity tag may or may not be an MD5 digest of the object data. If you specified server-side encryption either with an Amazon S3-managed encryption key or an AWS KMS customer master key CMK in your initiate multipart upload request, the response includes this header.

It confirms the encryption algorithm that Amazon S3 used to encrypt the object. You can store individual objects of up to 5 TB in Amazon S3. When copying an object, you can preserve all metadata default or specify new metadata.

However, the ACL is not preserved and is set to private for the user making the request. For more information, see Using ACLs. Amazon S3 transfer acceleration does not support cross-region copies. If you request a cross-region copy using a transfer acceleration endpoint, you get a Bad Request error.

For more information about transfer acceleration, see Transfer Acceleration.The latest development version can always be found on GitHub. Before you can begin using Boto 3, you should set up authentication credentials. You can create or use an existing user. Go to manage access keys and generate a new set of keys. Alternatively, you can create the credential file yourself.

You may also want to set a default region. This can be done in the configuration file. This sets up credentials for the default profile as well as a default region to use when creating connections.

See Credentials for in-depth configuration sources and options. Now that you have an s3 resource, you can make requests and process responses from the service. The following uses the buckets collection to print out all bucket names:. It's also easy to upload and download binary data. For example, the following uploads a new file to S3. It assumes that the bucket my-bucket already exists:. Resources and Collections will be covered in more detail in the following sections, so don't worry if you do not completely understand the examples.

Navigation index modules next previous Boto 3 Docs 1. Boto 3 Docs 1. Docs Quickstart. Note The latest development version can always be found on GitHub. Print out bucket names for bucket in s3.

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Bucket 'my-bucket'. Boto 3 Documentation. A Sample Tutorial. Created using Sphinx.


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