R/botor.R

In daroczig/botor: 'AWS Python SDK' ('boto3') for R

#' Internal boto3 session
#' @keywords internal
botor_session <- NULL


#' The default, fork-safe Boto3 session
#' @param aws_access_key_id AWS access key ID
#' @param aws_secret_access_key AWS secret access key
#' @param aws_session_token AWS temporary session token
#' @param region_name Default region when creating new connections
#' @param botocore_session Use this Botocore session instead of creating a new default one
#' @param profile_name The name of a profile to use. If not given, then the default profile is used
#' @return boto3 \code{Session}
#' @export
botor <- function(aws_access_key_id, aws_secret_access_key, aws_session_token,
                  region_name, botocore_session, profile_name) {

    mc   <- match.call()
    args <- as.list(mc[-1])

    if (length(args) != 0 || is.null(botor_session) || botor_session_pid() != Sys.getpid()) {

        if (!is.null(botor_session) & length(args) == 0) {
            args <- attr(botor_session, 'args')
        }

        session <- do.call(boto3$session$Session, args)

        utils::assignInMyNamespace(
            'botor_session',
            structure(
                session,
                pid  = Sys.getpid(),
                uuid = uuid(),
                args = args))
    }

    botor_session

}


#' Look up the PID used to initialize the Boto3 session
#' @return int
#' @keywords internal
botor_session_pid <- function() {
    attr(botor_session, 'pid')
}


#' Look up the UUID of the initialized Boto3 session
#' @return int
#' @keywords internal
botor_session_uuid <- function() {
    attr(botor_session, 'uuid')
}


#' boto3 clients cache
#' @keywords internal
clients <- new.env()


#' Creates an initial or reinitialize an already existing AWS client or resource cached in the package's namespace
#' @param service string, eg S3 or IAM
#' @param type AWS service client or resource to be created, eg \code{s3}
#' @param cache booelan flag for caching the client or resource in the package namespace. For (internal) package functions, it's best to set to \code{TRUE} to avoid reinitializing the client/resource, but for custom use and when you need to use multiple clients for the same service in parallel (eg working with different regions etc), you might want to set this to \code{FALSE}
#' @param ... further parameters passed to the \code{client} or \code{resource}, eg \code{endpoint_url}
#' @references \url{https://boto3.amazonaws.com/v1/documentation/api/latest/reference/core/session.html}
#' @return cached AWS client
#' @importFrom checkmate assert_string assert_flag
#' @export
botor_client <- function(service, type = c('client', 'resource'), cache = TRUE, ...) {

    assert_string(service)
    assert_flag(cache)
    type <- match.arg(type)

    client <- tryCatch(
        get(service, envir = clients, inherits = FALSE),
        error = function(e) NULL)

    if (cache == TRUE && !is.null(client) && attr(client, 'uuid') == botor_session_uuid()) {
        return(client)
    }

    if (type == 'client') {
        client <- botor()$client(service, ...)
    } else {
        client <- botor()$resource(service, ...)
    }

    if (cache == FALSE) {
        return(client)
    }

    assign(x = service,
               value = structure(
                   client,
                   uuid = botor_session_uuid()),
           envir = clients)
    return(client)

}