R APIs

faasr_get_file

Usage: faasr_get_file(server_name, remote_folder, remote_file, local_folder, local_file)

This function gets (i.e. downloads) a file from an S3 bucket to be used by the FaaSr function.

server_name is a string with name of the S3 bucket to use; it must match a name declared in the workflow configuration JSON file. This is an optional argument; if not provided, the default S3 server specified as DefaultDataStore in the workflow configuration JSON file is used.

remote_folder is string with the name of the remote folder where the file is to be downloaded from. This is an optional argument that defaults to ""

remote_file is a string with the name for the file to be downloaded from the S3 bucket. This is a required argument.

local_folder is a string with the name of the local folder where the file to be downloaded is stored. This is an optional argument that defaults to "."

local_file is a string with the name for the file downloaded from the S3 bucket. This is a required argument.

Examples:

faasr_get_file(remote_folder="myfolder", remote_file="myinput1.csv", local_file="input1.csv")
faasr_get_file(server_name="My_Minio_Bucket", remote_file="myinput2.csv", local_file="input2.csv")

faasr_put_file

Usage: faasr_put_file(server_name, local_folder, local_file, remote_folder, remote_file)

This function puts (i.e. uploads) a file from the local FaaSr function to an S3 bucket.

server_name is a string with name of the S3 bucket to use; it must match a name declared in the workflow configuration JSON file. This is an optional argument; if not provided, the default S3 server specified as DefaultDataStore in the workflow configuration JSON file is used.

local_folder is a string with the name of the local folder where the file to be uploaded is stored. This is an optional argument that defaults to "."

local_file is a string with the name for the file to be uploaded to the S3 bucket. This is a required argument.

remote_folder is string with the name of the remote folder where the file is to be uploaded to. This is an optional argument that defaults to ""

remote_file is a string with the name for the file to be uploaded to the S3 bucket. This is a required argument.

Examples:

faasr_put_file(local_file="output.csv", remote_folder="myfolder", remote_file="myoutput.csv")
faasr_get_file(server_name="My_Minio_Bucket", local_file="output.csv", remote_file="myoutput.csv")

faasr_get_folder_list

Usage: folderlist <- faasr_get_folder_list(server_name, faasr_prefix)

This function returns a list with the contents of a folder in the S3 bucket.

server_name is a string with name of the S3 bucket to use; it must match a name declared in the workflow configuration JSON file. This is an optional argument; if not provided, the default S3 server specified as DefaultDataStore in the workflow configuration JSON file is used.

faasr_prefix is a string with the prefix of the folder in the S3 bucket. This is an optional argument that defaults to ""

Examples:

mylist1 <- faasr_get_folder_list(server_name="My_Minio_Bucket", faasr_prefix="myfolder")
mylist2 <- faasr_get_folder_list(server_name="My_Minio_Bucket", faasr_prefix="myfolder/mysubfolder")

faasr_delete_file

Usage: faasr_delete_file(server_name, remote_folder, remote_file)

This function deletes a file from the S3 bucket.

server_name is a string with name of the S3 bucket to use; it must match a name declared in the workflow configuration JSON file. This is an optional argument; if not provided, the default S3 server specified as DefaultDataStore in the workflow configuration JSON file is used.

remote_folder is string with the name of the remote folder where the file is to be deleted from. This is an optional argument that defaults to ""

remote_file is a string with the name for the file to be deleted from the S3 bucket. This is a required argument.

Examples:

faasr_delete_file(remote_folder="myfolder", remote_file="myoutput.csv")
faasr_delete_file(server_name="My_Minio_Bucket", remote_file="myoutput.csv")

faasr_arrow_s3_bucket

Usage: faasr_arrow_s3_bucket(server_name, faasr_prefix)

This function configures an S3 bucket to use with Apache Arrow.

server_name is a string with name of the S3 bucket to use; it must match a name declared in the workflow configuration JSON file. This is an optional argument; if not provided, the default S3 server specified as DefaultDataStore in the workflow configuration JSON file is used.

faasr_prefix is a string with the prefix of the folder in the S3 bucket. This is an optional argument that defaults to ""

It returns a list that is subsequently used with the Arrow package.

Examples:

mys3 <- faasr_arrow_s3_bucket()
myothers3 <- faasr_arrow_s3_bucket(server_name="My_Minio_Bucket", faasr_prefix="myfolder")
frame_input1 <- arrow::read_csv_arrow(mys3$path(file.path(folder, input1)))
frame_input2 <- arrow::read_csv_arrow(mys3$path(file.path(folder, input2)))
arrow::write_csv_arrow(frame_output, mys3$path(file.path(folder, output)))

faasr_log

Usage: faasr_log(log_message)

This function writes a log message to a file in the S3 bucket, to help with debugging. The default S3 server for logs is DefaultDataStore as specified in the workflow configuration JSON file. This default can be overridden with LoggingDataStore in the workflow configuration JSON file.

log_message is a string with the message to be logged.

Example:

log_msg <- paste0('Function compute_sum finished; output written to ', folder, '/', output, ' in default S3 bucket')
faasr_log(log_msg)

faasr_rank

Usage: faasr_rank()

Only applicable for workflows with functions that are triggered for concurrent execution using rank. This returns this function's invocation rank as a list with two values:

list$max_rank - an integer that determines to the maximum number of invocations (e.g. N) list$rank - an integer that determines this function's invocation rank (e.g. a number ranging from 1 to N)

Example:

In a workflow, suppose you have declared that a function start invokes a successor function compute with rank N=10, where each instance of compute works to produce an output file myoutput_i.csv, where i is a number from 1 to 10.

At runtime, start invokes 10 instances of compute; faasr_rank() determines the value of i for each instance of compute, which can be used to construct the file name:

rank_list <- faasr_rank()
my_rank <- rank_list$rank
max_rank <- rank_list$max_rank
local_file <- paste0("myinput_", my_rank, ".csv")
write.csv(my_data, local_file, row.names=FALSE)

faasr_invocation_id

Usage: faasr_invocation_id()

Returns this action's invocation ID.

Example:

invocation_id <- faasr_invocation_id()