ff.go

Documentation: edge-infra.dev/pkg/lib/featureflag

     1  package featureflag
     2  
     3  import (
     4  	"errors"
     5  	"os"
     6  	"time"
     7  
     8  	"github.com/launchdarkly/go-sdk-common/v3/ldcontext"
     9  	ld "github.com/launchdarkly/go-server-sdk/v6"
    10  )
    11  
    12  var (
    13  	client *ld.LDClient
    14  
    15  	recreateClient bool // this is set to true whenever the SetConfig function is called.
    16  	config         ld.Config
    17  )
    18  
    19  var ErrNoAPIKey = errors.New("LD_KEY not set")
    20  
    21  func Client() (*ld.LDClient, error) {
    22  	if client != nil && !recreateClient {
    23  		return client, nil
    24  	}
    25  	recreateClient = false
    26  
    27  	// if no LD_KEY is given, then a custom data source is required,
    28  	// The custom data source is set when testing using the testutil package.
    29  	key, hasKey := os.LookupEnv("LD_KEY")
    30  	if !hasKey && config.DataSource == nil {
    31  		return nil, ErrNoAPIKey
    32  	}
    33  	var err error
    34  	client, err = ld.MakeCustomClient(key, config, 10*time.Second)
    35  	return client, err
    36  }
    37  
    38  func SetConfig(c ld.Config) {
    39  	recreateClient = true
    40  	config = c
    41  }
    42  
    43  // FeatureEnabledForContext wraps BoolVariation to get the value of a boolean
    44  // feature flag for a particular LD Context.
    45  func FeatureEnabledForContext(ctxer Contextualizer, feature string, defaultVal bool) (bool, error) {
    46  	client, err := Client()
    47  	if err != nil {
    48  		return defaultVal, err
    49  	}
    50  	ldCtx := ldcontext.NewWithKind(ctxer.Kind(), ctxer.Key())
    51  	return client.BoolVariation(feature, ldCtx, defaultVal)
    52  }
    53  
    54  // FeatureEnabledForBanner is a helper wrapping [FeatureEnabledForContext] that automatically creates a
    55  // [BannerContext].
    56  func FeatureEnabledForBanner(feature, banner string, defaultVal bool) (bool, error) {
    57  	return FeatureEnabledForContext(NewBannerContext(banner), feature, defaultVal)
    58  }
    59  
    60  // FeatureEnabledForLDContext wraps BoolVariation to get the value of a boolean
    61  // feature flag for a particular LD Context.
    62  func FeatureEnabledForLDContext(feature string, ldcontext ldcontext.Context, defaultVal bool) (bool, error) {
    63  	client, err := Client()
    64  	if err != nil {
    65  		return defaultVal, err
    66  	}
    67  	return client.BoolVariation(feature, ldcontext, defaultVal)
    68  }
    69  
    70  // FeatureEnabled is a helper wrapping FeatureEnabledForContext that automatically creates an
    71  // EnvironmentContext, which is a rule not targeted to a specific Context.
    72  func FeatureEnabled(feature string, defaultVal bool) (bool, error) {
    73  	return FeatureEnabledForContext(NewEnvironmentContext(), feature, defaultVal)
    74  }
    75
View as plain text