05. Configuration

Two Ways to Manage Production vs Development Mode

{golem} provides two separate mechanisms for managing production and development modes in your Shiny applications:

1. R Options Approach: Using options(golem.app.prod = TRUE/FALSE) which is checked by app_prod() and app_dev() functions. This approach controls the behavior of {golem}’s development-aware utility functions like cat_dev(), print_dev(), message_dev(), and similar tools.

2. Configuration File Approach: Using the golem-config.yml file to store configuration values (including an app_prod setting) that can be retrieved in your application code using get_golem_config().

Important: These two mechanisms are independent and serve different purposes. The R option controls {golem}’s built-in development tools, while the config file provides a flexible way to store and retrieve application-specific settings. This vignette focuses on the configuration file approach.

About inst/golem-config.yml

When you start a new {golem} application, you’ll find a file called golem-config.yml in the inst/ folder.

By default, this file contains the name of your app, its version, and the default working directory (which is the root of your package).

This config file is based on the {config} format, which allows you to create configuration files for different application contexts. Please refer to this package documentation for more information.

Setting golem-config

Here is what the default config file looks like:

default:
  golem_name: golex
  golem_version: 0.0.0.9000
  app_prod: no

production:
  app_prod: yes

dev:
  golem_wd: !expr golem::pkg_path()

• default/golem_name, default/golem_version, default/app_prod can be used across the whole life of your {golem} app: while developing, and also when in production.
• production/app_prod can be used to add elements that are to be used once the app is in production.
• dev/golem_wd is in a dev config because the only moment you might reliably use this config is while developing your app. Use the app_sys() function if you want to rely on the package path once the app is deployed.

The good news is that if you don’t want/need to use {config}, you can safely ignore this file, just leave it where it is: it is used internally by the {golem} functions.

These options are globally set with:

set_golem_options()
#> Warning: `set_golem_options()` is a development function and should not be
#> called when {golem} is in production mode (`options('golem.app.prod' = TRUE)`).
#> ── Setting {golem} options in `golem-config.yml` ───────────────────────────────
#> Warning: `set_golem_name()` is a development function and should not be called
#> when {golem} is in production mode (`options('golem.app.prod' = TRUE)`).
#> ✔ Setting `golem_name` to golex
#> Warning: `set_golem_wd()` is a development function and should not be called
#> when {golem} is in production mode (`options('golem.app.prod' = TRUE)`).
#> ✔ Setting `golem_wd` to golem::pkg_path()
#> You can change golem working directory with set_golem_wd('path/to/wd')
#> Warning: `set_golem_version()` is a development function and should not be
#> called when {golem} is in production mode (`options('golem.app.prod' = TRUE)`).
#> ✔ Setting `golem_version` to 0.0.0.9000
#> ✔ Setting `app_prod` to FALSE
#> ── Setting {usethis} project as `golem_wd` ─────────────────────────────────────
#> ✔ Setting active project to
#>   "/private/var/folders/9w/zdlv83ws6csdjnfc5x819gtr0000gn/T/RtmpWIrsnE/golex".

default:
  golem_name: golex
  golem_version: 0.0.0.9000
  app_prod: no
production:
  app_prod: yes
dev:
  golem_wd: !expr golem::pkg_path()

The functions reading the options in this config file are:

get_golem_name()
#> [1] "golex"
get_golem_wd()
#> [1] "/private/var/folders/9w/zdlv83ws6csdjnfc5x819gtr0000gn/T/RtmpWIrsnE/golex"
get_golem_version()
#> [1] "0.0.0.9000"

You can set these with:

set_golem_name("this")
set_golem_wd(".")
set_golem_version("0.0.1")

default:
  golem_name: golex
  golem_version: 0.0.0.9000
  app_prod: no
production:
  app_prod: yes
dev:
  golem_wd: !expr golem::pkg_path()

Using golem-config

If you’re already familiar with the {config} package, you can use this file just as any config file.

{golem} comes with an amend_golem_config() function to add elements to it.

amend_golem_config(
  key = "where",
  value = "indev"
)
#> ✔ Setting `where` to indev
amend_golem_config(
  key = "where",
  value = "inprod",
  config = "production"
)
#> ✔ Setting `where` to inprod

Will result in a golem-config.yml file as such:

default:
  golem_name: golex
  golem_version: 0.0.0.9000
  app_prod: no
  where: indev
production:
  app_prod: yes
  where: inprod
dev:
  golem_wd: !expr golem::pkg_path()

app_config.R

In R/app_config.R, you’ll find a get_golem_config() function that allows you to retrieve config from this config file:

pkgload::load_all()
#> ℹ Loading golex
get_golem_config(
  "where"
)
#> [1] "indev"
get_golem_config(
  "where",
  config = "production"
)
#> [1] "inprod"

Or using the env var (default {config} behavior):

Sys.setenv("R_CONFIG_ACTIVE" = "production")
get_golem_config("where")
#> [1] "inprod"

golem_config vs golem_options

There are two ways to configure golem apps:

• The golem_opts in the run_app() function
• The golem-config.yml file

The main difference between these two is that the {golem} options from run_app() are meant to be configured during runtime: you’ll be doing run_app(val = "this"), whereas the golem-config is meant to be used in the backend, and will not be linked to the parameters passed to run_app() (even if this is technically possible, this is not the main objective).

The golem-config.yml file is also linked to the R_CONFIG_ACTIVE environment variable, just as any {config} file.

Additionally, the golem-config.yml file is shareable across {golem} projects (whereas golem_opts are application specific), and will be tracked by version control systems.

Connecting Back to the R Options Approach

As mentioned at the beginning of this vignette, {golem} uses two separate mechanisms for production/development configuration. While this vignette has focused on the golem-config.yml file, it’s important to understand how this relates to the R options approach.

# Example: sync config to R option (optional)
if (get_golem_config("app_prod")) {
  options(golem.app.prod = TRUE)
}

Note for {golem} < 0.2.0 users

If you’ve built an app with {golem} before the version 0.2.0, this config file doesn’t exist: you’ll be prompted to create it if you update a newer version of {golem}.