'RAVE' Context: Read and Set Context of Environments

Usage

rave_context(
  context,
  require_contexts,
  disallowed_context,
  error_msg,
  spos = 2L,
  senv,
  tpos = 1L,
  tenv
)

Arguments

context: context string for target environment, optional, see `Details'
require_contexts: characters, (optional): required context for current function. If any context is missing, the function will raise errors
disallowed_context: characters, (optional): defines the contexts that don't work for the function. If running within such contexts, the function will raise errors
error_msg: characters, (optional): if running in improper contexts, the message to display, will passed to stop
spos: levels to go up to search for senv, passed to parent.frame
senv: environment to read 'RAVE' contexts
tpos: levels to go up to search for tenv, passed to parent.frame
tenv: environment to set 'RAVE' contexts

Value

A list of current context, including the package name, module ID, and current ExecEnvir instance if running under "rave_running"

context.

Details

Context strings tells the function which context it's running, and it will affect the behaviors of functions within its environment. Because 'RAVE' modules are usually R packages, the context strings help the module writers determine where the function is running. For example, running locally, or in 'RAVE' container, or debug mode. A typical example would be get_path function. All external scripts used in R packages require to be obtained using system.file. However, because the files are subject to change, using system file function requires re-compile the package, which is time-consuming. Function get_path returns the file path relative to current working directory during the development (in "default" context), and it calls system.file when 'RAVE' instance is running.

There are four contexts: "default", "rave_module_debug", "rave_running", and "rave_running_local".

default: Default context: this means the function is running without any additional information.
rave_module_debug: Debug mode: used to develop and debug modules locally. Under the context, the function will be aware of the package that module belongs to
rave_running: If the function is running under this context, this means it's running inside of shiny application (usually within start_rave). The function will be able to get more contexts such as module ID, and current runtime environment (ExecEnvir)
rave_running_local: Similar to "rave_running", but without run-time environment. Under this context, the module is running locally without shiny. All reactive observers are disabled, and the modules will be compiled into a function with all the inputs defined by define_input as arguments, and code within "main.R" as the main body of the function.

Function rave_context uses reserved variables in the environment: .__rave_context__., .__rave_package__., .__rave_module__., and .__rave_module_instance__.. Please don't use these variables for other purposes. See `Examples' for how to set and read the context.

Examples

# ------- 1. Read/Set Context ---------

library(dipsaus)
library(rave)
# Reset context for current environment
rave_context('default')

# Read from current caller's environment
fun <- function(...){
  ctx <- rave_context()
  cat2('The function is running under context - ', ctx$context)
  cat2('The package under the context - ', ctx$package)
  cat2('Module ID is - ', ctx$module_id)
  cat2('Running instance is - ', ctx$instance)
}
fun()
#> The function is running under context -  default 
#> The package under the context -   
#> Module ID is -   
#> Running instance is -  
## The function is running under context - default
## The package under the context - 
## ...

# Set debug context 
debug_env <- new.env()
rave_context('rave_module_debug', tenv = debug_env)
debug_env$.__rave_package__. <- 'ravebuiltins'

# With debug_env, the function is aware of the package it's under
with(debug_env, { fun() })
#> The function is running under context -  rave_module_debug 
#> The package under the context -  ravebuiltins 
#> Module ID is -   
#> Running instance is -  
## The function is running under context - rave_module_debug
## The package under the context - ravebuiltins
## ...

# To set context within the function and affect the functions inide
fun2 <- function(module_id){
  # Run rave_context and then set module ID
  rave_context('rave_running_local')
  .__rave_module__. <- module_id
  fun()
}
with(debug_env, { fun2('power_explorer') })
#> The function is running under context -  rave_running_local 
#> The package under the context -  ravebuiltins 
#> Module ID is -  power_explorer 
#> Running instance is -  
## The function is running under context - rave_running_local
## The package under the context - ravebuiltins
## Module ID is - power_explorer
## ...

# Let's see what we can do with rave_module_debug
with(debug_env, { get_path('inst/rave.yaml') })
# When I develop the package, it returns:
## "/Users/beauchamplab/.../ravebuiltins/inst/settings.yaml"
# When I run in other places, it returns
## "/Users/beauchamplab/Library/R/3.6/library/ravebuiltins/rave.yaml"


# ------- 2. Setting behaviors for context ---------
# One way to set different behaviors is to using `ctx`
if (FALSE) {
fun <- function(){
  ctx <- rave_context()
  switch(ctx$context, ...)
}
}

# The other way is to use S3 generics provided by R syntax
fun <- rave_context_generics('fun', function(module_id, ...){})

# action for default
fun.default <- function(...){
  cat2('Function is not supposed to run under default context...',
       level = 'ERROR')
}

# for debug, set module ID and run with rave_running_local
fun.rave_module_debug <- function(module_id, ...){
  cat2('Debug mode... loading a test subject')
  # Do something ... like automatically mount_demo_subject
  # by running mount_demo_subject()
  
  rave_context('rave_running_local')
  .__rave_module__. <- module_id
  # Recall the function under rave_running_local context
  fun(module_id, ...)
}

# When running within RAVE container, local and with shiny
fun.rave_running_local <- function(...){
  ctx <- rave_context()
  cat2('Yay, running ', ctx$module_id, ' under context ',
       ctx$context, level='INFO')
}
fun.rave_running <- fun.rave_running_local

# Run in default mode, expect error message
fun('power_explorer')
#> Function is not supposed to run under default context... 

# Run in debug mode
debug_env <- new.env()
rave_context('rave_module_debug', tenv = debug_env)
debug_env$.__rave_package__. <- 'ravebuiltins'

# The function will run in debug mode, then rave_running_local
with(debug_env, { fun('power_explorer') })
#> Debug mode... loading a test subject 
#> Yay, running  power_explorer  under context  rave_running_local