Quick how to:

# drat::addRepo(account = "Ignacio", alturl = "https://drat.ignacio.website/")
# install.packages("IMS3")
library("IMS3")

## Loading required package: aws.s3

set.enviroment()
bucketlist()

##   c..ignacios.test.bucket....2019.03.19T13.21.52.000Z..
## 1                                  ignacios-test-bucket
## 2                              2019-03-19T13:21:52.000Z

# save an in-memory R object into S3
s3save(mtcars, bucket = "ignacios-test-bucket", object = "mtcars.Rdata")

# `load()` R objects from the file
s3load("mtcars.Rdata", bucket = "ignacios-test-bucket")

Video talking about this:

Using S3 from within an EC2 instance

I added the aws.signature to my imremoter docker container. This allows me to interact with S3 buckets from within an EC2 instance without having to setup my credentials. The only thing you need to do is create a role that has gives the EC2 instance permission to interact with S3. Here is a short video where I talk about this: