config.go

package unleash

import (
	"net/http"
	"net/url"
	"time"

	"github.com/Unleash/unleash-client-go/v4/api"
	"github.com/Unleash/unleash-client-go/v4/context"
	"github.com/Unleash/unleash-client-go/v4/strategy"
)

type configOption struct {
	appName         string
	environment     string
	instanceId      string
	url             string
	projectName     string
	refreshInterval time.Duration
	metricsInterval time.Duration
	disableMetrics  bool
	backupPath      string
	strategies      []strategy.Strategy
	listener        interface{}
	storage         Storage
	httpClient      *http.Client
	customHeaders   http.Header
}

// ConfigOption represents a option for configuring the client.
type ConfigOption func(*configOption)

// WithListener allows users to register a type that implements one or more of
// the listener interfaces. If no listener is registered then the user is responsible
// for draining the various channels on the client. Failure to do so will stop the client
// from working as the worker routines will be blocked.
func WithListener(listener interface{}) ConfigOption {
	return func(o *configOption) {
		o.listener = listener
	}
}

// WithAppName specifies the name of the application.
func WithAppName(appName string) ConfigOption {
	return func(o *configOption) {
		o.appName = appName
	}
}

// WithEnvironment specifies the environment
func WithEnvironment(env string) ConfigOption {
	return func(o *configOption) {
		o.environment = env
	}
}

// WithInstanceId specifies the instance identifier of the current instance. If not provided,
// one will be generated based on various parameters such as current user and hostname.
func WithInstanceId(instanceId string) ConfigOption {
	return func(o *configOption) {
		o.instanceId = instanceId
	}
}

// WithUrl specifies the url of the unleash server the user is connecting to.
func WithUrl(url string) ConfigOption {
	return func(o *configOption) {
		o.url = url
	}
}

// WithRefreshInterval specifies the time interval with which the client should sync the
// feature toggles from the unleash server (default 15s).
func WithRefreshInterval(refreshInterval time.Duration) ConfigOption {
	return func(o *configOption) {
		o.refreshInterval = refreshInterval
	}
}

// WithMetricsInterval specifies the time interval with which the client should upload
// the metrics data to the unleash server (default 60s).
func WithMetricsInterval(metricsInterval time.Duration) ConfigOption {
	return func(o *configOption) {
		o.metricsInterval = metricsInterval
	}
}

// WithDisableMetrics specifies that the client should not log metrics to the unleash server.
func WithDisableMetrics(disableMetrics bool) ConfigOption {
	return func(o *configOption) {
		o.disableMetrics = disableMetrics
	}
}

// WithBackupPath specifies the path that is passed to the storage implementation for storing
// the feature toggles locally.
func WithBackupPath(backupPath string) ConfigOption {
	return func(o *configOption) {
		o.backupPath = backupPath
	}
}

// WithStrategies specifies which strategies (in addition to the defaults) should be used by the
// client.
func WithStrategies(strategies ...strategy.Strategy) ConfigOption {
	return func(o *configOption) {
		o.strategies = strategies
	}
}

// WithStorage specifies which storage implementation the repository should use for storing feature
// toggles.
func WithStorage(storage Storage) ConfigOption {
	return func(o *configOption) {
		o.storage = storage
	}
}

// WithHttpClient specifies which HttpClient the client should use for making requests to the server.
func WithHttpClient(client *http.Client) ConfigOption {
	return func(o *configOption) {
		o.httpClient = client
	}
}

// WithCustomHeaders specifies any custom headers that should be sent along with requests to the
// server.
func WithCustomHeaders(headers http.Header) ConfigOption {
	return func(o *configOption) {
		o.customHeaders = headers
	}
}

// WithProjectName defines a projectName on the config object and is used to
// filter toggles by project name.
func WithProjectName(projectName string) ConfigOption {
	return func(o *configOption) {
		o.projectName = projectName
	}
}

// FeatureResolver represents a function to be called to resolve the feature instead of using the repository
type FeatureResolver func(feature string) *api.Feature

// WithResolver allows you to bypass the repository when resolving a feature name to its actual instance.
func WithResolver(resolver FeatureResolver) FeatureOption {
	return func(opts *featureOption) {
		opts.resolver = resolver
	}
}

// FallbackFunc represents a function to be called if the feature is not found.
type FallbackFunc func(feature string, ctx *context.Context) bool

type featureOption struct {
	fallback     *bool
	fallbackFunc FallbackFunc
	ctx          *context.Context
	resolver     FeatureResolver
}

// FeatureOption provides options for querying if a feature is enabled or not.
type FeatureOption func(*featureOption)

// WithFallback specifies what the value should be if the feature toggle is not found on the
// unleash service.
func WithFallback(fallback bool) FeatureOption {
	return func(opts *featureOption) {
		opts.fallback = &fallback
	}
}

// WithFallbackFunc specifies a fallback function to evaluate a feature
// toggle in the event that it is not found on the service.
func WithFallbackFunc(fallback FallbackFunc) FeatureOption {
	return func(opts *featureOption) {
		opts.fallbackFunc = fallback
	}
}

// WithContext allows the user to provide a context that will be passed into the active strategy
// for determining if a specified feature should be enabled or not.
func WithContext(ctx context.Context) FeatureOption {
	return func(opts *featureOption) {
		opts.ctx = &ctx
	}
}

// WithVariantContext specifies a context for the GetVariant
// call
func WithVariantContext(ctx context.Context) VariantOption {
	return func(opts *variantOption) {
		opts.ctx = &ctx
	}
}

// WithVariantResolver allows you to bypass the repository when resolving a feature name to its actual instance.
func WithVariantResolver(resolver FeatureResolver) VariantOption {
	return func(opts *variantOption) {
		opts.resolver = resolver
	}
}

// VariantFallbackFunc represents a function to be called if the variant is not found.
type VariantFallbackFunc func(feature string, ctx *context.Context) *api.Variant

type variantOption struct {
	variantFallback     *api.Variant
	variantFallbackFunc VariantFallbackFunc
	ctx                 *context.Context
	resolver            FeatureResolver
}

// VariantOption provides options for querying if a variant is found or not.
type VariantOption func(*variantOption)

// WithVariantFallback specifies what the value should be if the
// variant is not found on the unleash service. This could be because
// the feature doesn't exist, because it is disabled, or because it
// has no variants.
//
// If you specify a fallback variant, note that its `FeatureEnabled`
// field will be set to whatever you pass in or `false` by default. In
// other words, it will not reflect the feature's actual enabled
// state.
func WithVariantFallback(variantFallback *api.Variant) VariantOption {
	return func(opts *variantOption) {
		opts.variantFallback = variantFallback
	}
}

// WithVariantFallbackFunc specifies a fallback function to evaluate
// to a variant when a variant is not found for a feature. This could
// be because the feature doesn't exist, because it is disabled, or
// because it has no variants.
//
// If you specify a fallback variant, note that its `FeatureEnabled`
// field will be set to whatever you pass in or `false` by default. In
// other words, it will not reflect the feature's actual enabled
// state.
func WithVariantFallbackFunc(variantFallbackFunc VariantFallbackFunc) VariantOption {
	return func(opts *variantOption) {
		opts.variantFallbackFunc = variantFallbackFunc
	}
}

type repositoryOptions struct {
	appName         string
	instanceId      string
	projectName     string
	url             url.URL
	backupPath      string
	refreshInterval time.Duration
	storage         Storage
	httpClient      *http.Client
	customHeaders   http.Header
}

type metricsOptions struct {
	appName         string
	instanceId      string
	url             url.URL
	strategies      []string
	metricsInterval time.Duration
	disableMetrics  bool
	httpClient      *http.Client
	customHeaders   http.Header
	started         *time.Time
}