featureflag

Documentation

Overview

Package featureflag implements simple feature-flagging. Feature flags can become an anti-pattern if abused. We should try to use them for two use-cases:

• `Preview` feature flags enable a piece of functionality we haven't yet fully baked. The user needs to 'opt-in'. We expect these flags to be removed at some time. Normally these will default to false.
• Escape-hatch feature flags turn off a default that we consider risky (e.g. pre-creating DNS records). This lets us ship a behaviour, and if we encounter unusual circumstances in the field, we can allow the user to turn the behaviour off. Normally these will default to true.

Feature flags are set via a single environment variable. The value is a string of feature flag keys separated by sequences of whitespace and comma. Each key can be prefixed with `+` (enable flag) or `-` (disable flag). Without prefix the flag gets enabled.

Index

• Constants
• Variables
• func Bool(b bool) *bool
• func ParseFlags(f string)
• type FeatureFlag
  • func New(key string, defaultValue *bool) *FeatureFlag
  • func (f *FeatureFlag) Enabled() bool

Constants

const (
	// Name is the name of the environment variable which encapsulates feature flags.
	Name = "STEWARD_FEATURE_FLAGS"
)

Variables

var (
	// Dummy shows how to define a feature flag. DO NOT USE IT!
	Dummy = New("Dummy", Bool(false))

	// CreateAuxNamespaceIfUnused controls whether auxiliary namespaces for
	// pipeline runs are created although they are not used.
	CreateAuxNamespaceIfUnused = New("CreateAuxNamespaceIfUnused", Bool(false))

	// RetryOnInvalidPipelineRunsConfig controls whether the execution of a pipeline run
	// is failed or retried on pipeline run configuration errors.
	RetryOnInvalidPipelineRunsConfig = New("RetryOnInvalidPipelineRunsConfig", Bool(false))
)

Functions

func Bool

func Bool(b bool) *bool

Bool returns a pointer to the boolean value.

func ParseFlags

func ParseFlags(f string)

ParseFlags is responsible for parse out the feature flag usage.

Types

type FeatureFlag

type FeatureFlag struct {
	Key string
	// contains filtered or unexported fields
}

FeatureFlag defines a feature flag

func New

func New(key string, defaultValue *bool) *FeatureFlag

New creates a new feature flag.

func (*FeatureFlag) Enabled

func (f *FeatureFlag) Enabled() bool

Enabled checks if the flag is enabled.