Reading object in s3 bucket from ecs fargate task

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• a possible bug
• a question about package functionality
• a suggested code or documentation change, improvement to the code, or feature request

I have a shiny app running on an ecs fargate task using the rocker:shiny-verse base docker image. I can't read an s3 file
within the initialisation of the shiny app (global.R file). Interestingly it does work when I change the method of serving the app in the docker file.

The docker command that works is:

CMD ["R", "-e", "shiny::runApp('/srv/shiny-server/my_app', 3838, host='0.0.0.0')"]

And the method I want to use but doesn't work:

CMD ["/usr/bin/shiny-server.sh"]

What is the intended method of accessing the permissions granted to the IAM role, how can I read from the s3 bucket within an ecs fargate task?

My global.R file looks like this:

## load package
library(ini)
library("aws.ec2metadata")

Sys.setenv("AWS_DEFAULT_REGION" = "eu-west-2")
if (is_ecs() == T) {
   metadata$iam_role("ecsTaskExecutionRole")
}

config = aws.s3::s3read_using(read.ini,
                              object = 'my_object.ini',
                              bucket = 'my_bucket')

I can't get the session Info of the Fargate task or any logs but know it's the s3 connection that is failing as removing the
s3_read_using() call allows the app to run as expected. I have also double checked that the ecsTaskExecutionRole has s3 read
permissions required. The bucket also definitely exists and as does the object and it's in the correct region (eu-west-2).

Start with the global.R example and compare the Dockerfile CMD using shiny::runApp with /usr/bin/shiny-server.sh. Trace aws.ec2metadata::metadata$iam_role, aws.s3::s3read_using, and the ECS task's IAM access, using the available task logs or session information if possible. Done means the intended credential method and a working S3 read from the Fargate task are established.