feat: create structs representing Featurevisor instance and config manager

.gitignore

@@ -0,0 +1,21 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+
+# Local IDE configuration
+.idea/

config/config.go

@@ -0,0 +1,14 @@
+package config
+
+// Config represents a parsed datafile config.
+type Config interface {
+	GetDatafile() []byte
+	GetRevision() string
+	// ...rest of the methods
+}
+
+// ConfigManager represents a configuration manager that reads and holds datafile config.
+type ConfigManager interface {
+	GetConfig() (Config, error)
+	Sync() error
+}

config/static_config.go

@@ -0,0 +1,52 @@
+package config
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"sync"
+)
+
+type StaticConfigManager struct {
+	datafileURL string
+	datafile    []byte
+	client      *http.Client
+	config      Config
+	lock        sync.Mutex
+	logger      interface{}
+}
+
+func (configManager *StaticConfigManager) GetConfig() (Config, error) {
+	configManager.lock.Lock()
+	defer configManager.lock.Unlock()
+
+	return configManager.config, nil
+}
+
+func (configManager *StaticConfigManager) Sync() error {
+	configManager.lock.Lock()
+	defer configManager.lock.Unlock()
+
+	url := configManager.datafileURL
+	datafile, err := http.Get(url)
+	if err != nil {
+		return fmt.Errorf("error while loading datafile: %w", err)
+	}
+
+	// Read the body of the response into a byte array
+	defer datafile.Body.Close()
+	body, err := io.ReadAll(datafile.Body)
+	if err != nil {
+		return fmt.Errorf("error while reading datafile: %w", err)
+	}
+
+	configManager.datafile = body
+	return nil
+}
+
+func NewStaticConfigManager(datafileURL string) *StaticConfigManager {
+	return &StaticConfigManager{
+		datafileURL: datafileURL,
+		client:      http.DefaultClient,
+	}
+}

examples/main.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"fmt"
+	"github.com/featurevisor/featurevisor-go"
+)
+
+func main() {
+	datafileURL := "https://featurevisor.com/datafile.yml"
+
+	instance, err := featurevisor.NewInstance(datafileURL)
+	if err != nil {
+		fmt.Printf("Error creating Featurevisor: %s\n", err)
+		return
+	}
+
+	revision := instance.GetRevision()
+	fmt.Printf("Featurevisor datafile revision: %s\n", revision)
+}

featurevisor.go

@@ -0,0 +1,11 @@
+package featurevisor
+
+import "github.com/featurevisor/featurevisor-go/instance"
+
+func NewInstance(datafileURL string) (*instance.Instance, error) {
+	factory := &instance.Factory{
+		DatafileURL: datafileURL,
+	}
+
+	return factory.NewInstance()
+}

go.mod

@@ -3,6 +3,7 @@ module github.com/featurevisor/featurevisor-go
 go 1.21.3
 
 require (
-	github.com/blang/semver v3.5.1+incompatible // indirect
 	github.com/spaolacci/murmur3 v1.1.0 // indirect
+	github.com/blang/semver v3.5.1+incompatible // indirect
+    github.com/stretchr/testify v1.8.4 // indirect
 )

go.sum

@@ -2,3 +2,4 @@ github.com/blang/semver v3.5.1+incompatible h1:cQNTCjp13qL8KC3Nbxr/y2Bqb63oX6wdn
 github.com/blang/semver v3.5.1+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
 github.com/spaolacci/murmur3 v1.1.0 h1:7c1g84S4BPRrfL5Xrdp6fOJ206sU9y293DDHaoy0bLI=
 github.com/spaolacci/murmur3 v1.1.0/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=

instance/factory.go

@@ -0,0 +1,19 @@
+package instance
+
+import "github.com/featurevisor/featurevisor-go/config"
+
+type Factory struct {
+	DatafileURL string
+
+	logger interface{}
+}
+
+// Instance creates a new Featurevisor instance with passed datafile URL.
+func (factory *Factory) NewInstance() (*Instance, error) {
+	configManager := config.NewStaticConfigManager(factory.DatafileURL)
+
+	instance := &Instance{
+		ConfigManager: configManager,
+	}
+	return instance, nil
+}

instance/instance.go

@@ -0,0 +1,24 @@
+package instance
+
+import "github.com/featurevisor/featurevisor-go/config"
+
+type Instance struct {
+	ConfigManager config.ConfigManager
+
+	logger interface{}
+}
+
+// GetRevision returns the revision of the datafile
+func (instance *Instance) GetRevision() string {
+	return ""
+}
+
+// GetBucketKey returns the bucket key for the given feature name
+func (instance *Instance) GetBucketKey(featureName string) string {
+	return ""
+}
+
+// Enabled returns true if the feature is enabled
+func (instance *Instance) Enabled(featureName string) bool {
+	return false
+}