README
¶
SimpleFlags Evaluation Engine
Simple flags which introduce variables, expressions and rule engine
Overview
This is experimental project, do not use it in production!!!
- No Variations
- No Clauses
- No configuration kind (bool, number ...)
- No states (on, off)
- No segments (target groups)
- No private attributes or anonymous target
1. No variations
More than 80% of flags are bool flags and there is no reason to have just two values as variation. Many companies use variation "true" and "false" but on my engine true and false are reserved keywords. Following JSON and swagger spec engine use data types from specification. If we talk about multivariate flags like strings, number etc. than probably there is a reason to have variation but if we look into flags there is no variations sharing between flags, so I don't see a reason to have variations at all.
2. No custom rules and clauses
Clauses are hard to read and to maintain so IMO I think there are better ways like rule engine evaluations. instead of maintaining schema for complex clauses better use expression language.
dev:
value: true
expression: target.identifier in beta
3. No configuration kind (bool, number ...)
No reason to have flag/configuration kind and engine supports dynamic nature of flags, so if flag serves bool than the flag is boolean. One thing why engine is different from others it can serve any values as you wish:
- Bool
- Number
- String
- Map
- Slice
evaluate("some_flag", target).Bool(defaultValue)
if some_flag serves string values 'true' or 'false' you can call bool or string methods it will give same results.
4. No states (on, off)
Instead of "on" or "off" there is simple bool field on: bool, if flag is on then 'on' will be true.
5. No segments (target groups)
This is the most interesting part there are no target groups or segments. So we are introducing concept of variables why variables? Because feature flags are remote "if" or online "if" and if is part of the language so variables are more suitable. Variable can have any data type like bool, string, number, slice, map. Variables can be used as serving values and values used in rule engine. Variables can be global and local. Local variables are used in the project and globals outside of the project. Imagine if you have paid customers and you want to share among different projects then you can specify global variable paidCustomers.
paidCustomers = [
'enver', 'bisevac'
]
and in flag rule expr:
target.name in paidCustomers
Global variables and local variables can have the same name.
6. No private attributes or anonymous target
All targets are private so they are never stored and doesn't require any required field, you can put any property.
Documentation
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Index ¶
- Constants
- Variables
- func SetLogger(logger Logger)
- func Variables(expression string) ([]string, error)
- type Configuration
- type Configurations
- type DataProvider
- type Distribution
- type Evaluation
- func (v Evaluation) Bool(defaultValue bool) bool
- func (v Evaluation) Int(defaultValue int) int
- func (v Evaluation) IsNone() bool
- func (v Evaluation) Map(defaultValue map[string]interface{}) map[string]interface{}
- func (v Evaluation) Number(defaultValue float64) float64
- func (v Evaluation) String(defaultValue string) string
- type Evaluations
- type Evaluator
- type Logger
- type PercentageRollout
- type Prerequisite
- type Rule
- type Serve
- type Target
- type Variable
- type WeightedVariation
Constants ¶
const ( CreateFlagEvent = "create_flag" PatchFlagEvent = "patch_flag" DeleteFlagEvent = "delete_flag" CreateVariable = "create_var" PatchVariable = "patch_var" DeleteVariable = "delete_var" )
Variables ¶
var ( // ErrQueryProviderMissing ... ErrQueryProviderMissing = errors.New("query field is missing in evaluator") )
Functions ¶
Types ¶
type Configuration ¶
type Configuration struct {
Project string `json:"project"`
Environment string `json:"environment"`
Identifier string `json:"identifier"`
Deprecated bool `json:"deprecated"`
On bool `json:"on"`
OnValue interface{} `json:"onValue"`
OffValue interface{} `json:"offValue"`
Rules []Rule `json:"rules"`
Prerequisites []Prerequisite `json:"prerequisites"`
Version uint `json:"version"`
} // @name Configuration
type Configurations ¶
type Configurations []Configuration // @name Configurations
type DataProvider ¶
type DataProvider interface {
GetVariable(key string) (Variable, error)
GetConfiguration(key string) (Configuration, error)
}
DataProvider provides methods for segment and flag retrieval
type Distribution ¶
type Distribution struct {
BucketBy string `json:"bucketBy" validate:"required"`
Variations []WeightedVariation `json:"variations" validate:"required"`
} // @name Distribution
func (Distribution) IsEmpty ¶
func (d Distribution) IsEmpty() bool
type Evaluation ¶
type Evaluation struct {
Project string `json:"project"`
Environment string `json:"environment"`
Identifier string `json:"identifier"`
Value interface{} `json:"value"`
// contains filtered or unexported fields
} // @name Evaluation
func (Evaluation) Bool ¶
func (v Evaluation) Bool(defaultValue bool) bool
func (Evaluation) Int ¶
func (v Evaluation) Int(defaultValue int) int
func (Evaluation) IsNone ¶
func (v Evaluation) IsNone() bool
func (Evaluation) Map ¶
func (v Evaluation) Map(defaultValue map[string]interface{}) map[string]interface{}
func (Evaluation) Number ¶
func (v Evaluation) Number(defaultValue float64) float64
func (Evaluation) String ¶
func (v Evaluation) String(defaultValue string) string
type Evaluations ¶
type Evaluations []Evaluation // @name Evaluations
type Evaluator ¶
type Evaluator struct {
// contains filtered or unexported fields
}
Evaluator engine evaluates flag from provided query
func NewEvaluator ¶
func NewEvaluator(provider DataProvider) (*Evaluator, error)
NewEvaluator constructs evaluator with query instance
type Logger ¶
type Logger interface {
Debug(args ...interface{})
Debugf(template string, args ...interface{})
Info(args ...interface{})
Infof(template string, args ...interface{})
Warn(args ...interface{})
Warnf(template string, args ...interface{})
Error(args ...interface{})
Errorf(template string, args ...interface{})
Panic(args ...interface{})
Panicf(template string, args ...interface{})
Fatal(args ...interface{})
Fatalf(template string, args ...interface{})
}
type PercentageRollout ¶
type PercentageRollout struct {
Expression string `json:"expression"`
Serve map[interface{}]interface{}
} // @name PercentageRollout
type Prerequisite ¶
type Prerequisite struct {
Feature string `json:"feature" validate:"required"`
Value interface{} `json:"value" validate:"required"`
} // @name Prerequisite
type Rule ¶
type Rule struct {
Expression string `json:"expression"`
Value interface{} `json:"value"`
} // @name Rule
type Serve ¶
type Serve struct {
Distribution *Distribution `json:"distribution,omitempty"`
Variation *string `json:"variation,omitempty"`
} // @name Serve
type Variable ¶
type Variable struct {
Identifier string `json:"identifier"`
Value interface{} `json:"value"`
} // @name Var
Source Files