Help for package featureflag

Title:

Turn Features On and Off using Feature Flags

Version:

0.2.0

Description:

Feature flags allow developers to turn features of their software on and off in form of configuration. This package provides functions for creating feature flags in code. It exposes an interface for defining own feature flags which are enabled based on custom criteria.

License:

MIT + file LICENSE

Encoding:

UTF-8

RoxygenNote:

7.3.2

Suggests:

testthat (≥ 3.0.0), spelling, knitr, rmarkdown, shiny, withr

Language:

en-US

URL:

https://github.com/szymanskir/featureflag

BugReports:

https://github.com/szymanskir/featureflag/issues

VignetteBuilder:

knitr

Config/testthat/edition:

NeedsCompilation:

Packaged:

2025-03-22 22:17:46 UTC; Rysza

Author:

Ryszard Szymański [aut, cre]

Maintainer:

Ryszard Szymański <ryszard.szymanski@outlook.com>

Repository:

CRAN

Date/Publication:

2025-03-22 22:30:01 UTC

Creates an instance of a bool feature flag with the specified bool value.

Description

Creates an instance of a bool feature flag with the specified bool value.

Usage

create_bool_feature_flag(value)

Arguments

value

single logical determining whether the flag should be enabled

Value

feature flag object of the bool value

Examples

{
  enabled_flag <- create_bool_feature_flag(TRUE)
  disabled_flag <- create_bool_feature_flag(FALSE)
}

Creates an instance of a connect feature flag that is enabled for specific groups

Description

Creates an instance of a connect feature flag that is enabled for specific groups

Usage

create_connect_group_feature_flag(groups)

Arguments

groups

groups for which the feature flag should be enabled

Value

feature flag that is enabled for specific groups

Examples

{
  connect_group_flag <- create_connect_group_feature_flag(groups = c("group1", "group2"))
}

Creates an instance of a connect feature flag that is enabled for specific users

Description

Creates an instance of a connect feature flag that is enabled for specific users

Usage

create_connect_user_feature_flag(users)

Arguments

users

users for which the feature flag should be enabled

Value

feature flag that is enabled for specific users

Examples

{
  connect_user_flag <- create_connect_user_feature_flag(users = c("user1", "user2"))
}

Creates an instance of a feature flag that is enabled based on an environment variable

Description

Creates an instance of a feature flag that is enabled based on an environment variable

Usage

create_env_var_feature_flag(env_var)

Arguments

env_var

Name of the environment variable

Value

Feature flag that is enabled based on the specified environment variable

Examples

{
  env_flag <- create_env_var_feature_flag(env_var = "FEATURE_X")
}

Creates the base of a feature flag.

Description

It should not be used directly, but only as a prerequisite when creating concrete feature flag.

Usage

create_feature_flag()

Value

instance of a base feature flag.

Creates an instance of a percentage feature flag with a specified chance of being enabled

Description

Creates an instance of a percentage feature flag with a specified chance of being enabled

Usage

create_percentage_feature_flag(percentage)

Arguments

percentage

chance of being enabled e.g. 1 for always being enabled

Value

feature flag object of the percentage type

Examples

{
  always_enabled_flag <- create_percentage_feature_flag(percentage = 1)
  randomly_enabled_flag <- create_percentage_feature_flag(percentage = 0.5)
}

Creates an instance of a time period feature flag.

Description

Creates an instance of a time period feature flag.

Usage

create_time_period_feature_flag(from = NULL, to = NULL)

Arguments

from

date-time from which the feature flag should be enabled set as null if you want a one sided boundary.

to

date-time to which the feature flag should be enabled set as null if you want a one sided boundary

Details

Boundaries are set as inclusive

Examples

{
  two_sided_flag <- create_time_period_feature_flag(
    from = ISOdatetime(2020, 10, 10, 0, 0, 0, tz = "UTC"),
    to = ISOdatetime(2020, 11, 10, 0, 0, 0, tz = "UTC")
  )

  left_sided_flag <- create_time_period_feature_flag(
    from = ISOdatetime(2020, 10, 10, 0, 0, 0, tz = "UTC")
  )

  right_sided_flag <- create_time_period_feature_flag(
    to = ISOdatetime(2020, 10, 10, 0, 0, 0, tz = "UTC")
  )
}

Evaluates the provided expression if the feature flag is enabled.

Description

Evaluates the provided expression if the feature flag is enabled.

Usage

feature_if(feature_flag, expr)

Arguments

feature_flag

flag which defines whether the provided expression should be evaluated

expr

expression to evaluate when the feature_flag is enabled

Details

The passed expression is evaluated in the frame where feature_if is called.

Value

If the passed feature_flag is enabled, than the result of the evaluation of the passed expression is returned. Otherwise there is no return value.

Examples

{
  flag <- create_bool_feature_flag(TRUE)

  feature_if(flag, {
    2 + 7
  })
}

Evaluates one or the other expression based on whether the feature flag is enabled.

Description

Evaluates one or the other expression based on whether the feature flag is enabled.

Usage

feature_ifelse(feature_flag, true_expr, false_expr)

Arguments

feature_flag

flag which defines which expression should be evaluated

true_expr

expression to evaluate when the feature_flag is enabled

false_expr

expression to evaluate when the feature_flag is disabled

Details

The passed expression is evaluated in the frame where feature_ifelse is called.

Value

The result of evaluating true_expr is returned if the passed feature_flag is enabled. Otherwise the result of evaluating false_expr is returned.

Examples

{
  flag <- create_bool_feature_flag(TRUE)

  feature_ifelse(
    flag,
    2 * 7,
    3 * 7
  )
}

Checks if the given feature flag is enabled.

Description

Checks if the given feature flag is enabled.

Usage

is_enabled(feature_flag)

Arguments

feature_flag

feature flag to be tested whether it is enabled

Value

TRUE if the feature flag is enabled.

Checks if the given bool feature flag is enabled

Description

Checks if the given bool feature flag is enabled

Usage

## S3 method for class 'bool_feature_flag'
is_enabled(feature_flag)

Arguments

feature_flag

flag to be checked whether it is enabled

Value

TRUE if the feature flag is enabled.

Examples

{
  enabled_flag <- create_bool_feature_flag(TRUE)

  if (is_enabled(enabled_flag)) {
    print("The flag is enabled!")
  }
}

Checks if the given connect group feature flag is enabled

Description

Checks if the given connect group feature flag is enabled

Usage

## S3 method for class 'connect_group_feature_flag'
is_enabled(feature_flag)

Arguments

feature_flag

flag to be checked whether it is enabled

Details

The session$groups field is used for retrieving the information on the logged-in user groups

Value

TRUE if the logged in user belongs to a group defined in the feature flag

Examples

{
  flag <- create_connect_group_feature_flag(c("group1"))

  # Returns TRUE when the logged-in user belongs to at least one of the specified groups
  mock_session <- shiny::MockShinySession$new()
  mock_session$groups <- "group1"
  shiny::withReactiveDomain(
    domain = mock_session,
    expr = is_enabled(flag)
  )

  # Returns FALSE if session$groups does not have any of the specified groups
  mock_session <- shiny::MockShinySession$new()
  mock_session$user <- "group2"
  shiny::withReactiveDomain(
    domain = mock_session,
    expr = is_enabled(flag)
  )
}

Checks if the given connect user feature flag is enabled

Description

Checks if the given connect user feature flag is enabled

Usage

## S3 method for class 'connect_user_feature_flag'
is_enabled(feature_flag)

Arguments

feature_flag

flag to be checked whether it is enabled

Details

The session$user field is used for retrieving the information on the logged-in user

Value

TRUE if the feature flag is enabled.

Examples

{
  flag <- create_connect_user_feature_flag(c("user1"))

  # Returns TRUE if the session$user matches the specified users
  mock_session <- shiny::MockShinySession$new()
  mock_session$user <- "user1"
  shiny::withReactiveDomain(
    domain = mock_session,
    expr = is_enabled(flag)
  )

  # Returns FALSE if the session$user does not match the specified users
  mock_session <- shiny::MockShinySession$new()
  mock_session$user <- "user2"
  shiny::withReactiveDomain(
    domain = mock_session,
    expr = is_enabled(flag)
  )
}

Checks if the given environment variable feature flag is enabled

Description

Checks if the given environment variable feature flag is enabled

Usage

## S3 method for class 'env_var_feature_flag'
is_enabled(feature_flag)

Arguments

feature_flag

Flag to be checked whether it is enabled

Value

TRUE if the environment variable is set to 'true'

Examples

{
  flag <- create_env_var_feature_flag("FEATURE_X")

  withr::with_envvar(new = list(FEATURE_X = "true"), {
    is_enabled(flag) # Returns TRUE
  })

  is_enabled(flag) # Returns FALSE by default
}

Checks if the given percentage flag is enabled

Description

Checks if the given percentage flag is enabled

Usage

## S3 method for class 'percentage_feature_flag'
is_enabled(feature_flag)

Arguments

feature_flag

flag to be checked whether it is enabled

Value

TRUE if the feature flag is enabled.

Examples

{
  enabled_flag <- create_percentage_feature_flag(1)

  if (is_enabled(enabled_flag)) {
    print("The flag is enabled!")
  }
}

Checks if the given bool feature flag is enabled

Description

Checks if the given bool feature flag is enabled

Usage

## S3 method for class 'time_period_feature_flag'
is_enabled(feature_flag)

Arguments

feature_flag

flag to be checked whether it is enabled

Value

TRUE if the feature flag is enabled.

Examples

{
  feature_flag <- create_time_period_feature_flag(
    from = ISOdatetime(2020, 10, 10, 0, 0, 0, tz = "UTC")
  )

  if (is_enabled(feature_flag)) {
    print("The flag is enabled!")
  }
}