Python download a file and upload to s3

I can now move on to making a publically readable bucket which will serve as the top level container for file objects within S3. At this point I can upload files to this newly created buchet using the Boto3 Bucket resource class. Below is a demo file named children. In conjunction with good practice of reusability I'll again make a function to upload files given a file path and bucket name as shown below.

The parameters to this method are a little confusing so let me explain them a little. First you have the Filename parameter which is actually the path to the file you wish to upload then there is the Key parameter which is a unique identifier for the S3 object and must confirm to AWS object naming rules similar to S3 buckets.

While uploading a file that already exists on the filesystem is a very common use case when writing software that utilizes S3 object based storage there is no need to write a file to disk just for the sole purpose of uploading it to S3. You can instead upload any byte serialized data in a using the put Below I am showing another new resuable function that takes bytes data, a bucket name and an s3 object key which it then uploads and saves to S3 as an object. Next I'll demonstrate downloading the same children.

There will likely be times when you are only downloading S3 object data to immediately process then throw away without ever needing to save the data locally. One thing to understand here is that AWS uses sessions. Similar to when you login to the web console a session is initiated with a cookie and everything in a similar way this can be done programmatically. So the first thing we need to do before we start accessing any resource in our AWS environment is to start and setup our session.

In order to do that we will leverage the library we installed earlier called dotenv. The reason we will use this is to access our secret and access key from the environment file. We use an environment file for security reasons such as avoiding to hardcode any values in our code base. The environment file basically tells Python that the data will live in the process environment which is in memory and does not touch any source file.

In a way this is similar to setting environment variables in your terminal but for convenience we set them in our. The format of this would look something like this:. The data values above have been randomized for obvious reasons. But as you can see we are setting two variables here one for our access and one for our secret key which our code will be reading from in order to use them to initialize our AWS session. This can be seen in the code below:.

Now that we have our keys setup we will talk about how to upload a file using Boto3 S3. We will start by uploading a local file to our S3 bucket. The code we will be writing and executing will leverage the boto3 helper python code we wrote above.

The steps to accomplish this are the following:. One thing to note here is that we are uploading 2 files test. This assumes you have created the files locally if not you can use the ones from the git repo and you need to have created a bucket as it was shown earlier called unbiased-coder-bucket.

If you choose a different name just replace the code above accordingly with the bucket name you chose to use. If we were to execute the code above you would see it in the output:. This shows that we successfully uploaded two files in our S3 bucket in AWS. To verify that everything worked for now we can login to the AWS console and see if the files are there. Later in the article we will demonstrate how to do this programmatically. If you were to login to the AWS console you will see something like this:.

In the above scenario basically the file will be uploaded into the prefix-dir from the root of our unbiased-coder-bucket. In this section we will go over on how to download a file using Boto3 S3, similar to uploading a file to S3 we will implement the download functionality:.

The code above will download from our bucket the previously two files we uploaded to it. The answer is no because the last argument of the download file is the destination path. Lets demonstrate the execution of this example:. Next we will discuss on how to list files using Boto3 S3 from our bucket. This is particularly useful when scripting code as a batch job that runs periodically and also acts as a verification that your data is there when it should be.

In the instance above we are not applying any filters on the objects we are requesting but we can easily do that if we wanted too. If using a script or library boto it would download the image to a file-system attached to the system it was running on - your local workstation or a server - and then use the AWS keys and libraries to upload it to S3.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Download a file directly to S3 Ask Question. Asked 8 years, 9 months ago. Active 5 years, 3 months ago. Viewed 6k times. David David Add a comment. Active Oldest Votes.