feat: kubernetes sync (#157)

open-feature/ofep#31
<img width="1512" alt="Screenshot 2022-08-30 at 15 54 16" src="https://user-images.githubusercontent.com/1235925/187469966-d3c137bd-1f1b-4ee7-9512-848951ec780b.png">

Signed-off-by: James-Milligan <[email protected]>
Signed-off-by: Alex Jones <[email protected]>
Signed-off-by: Alex Jones <[email protected]>
Co-authored-by: James Milligan <[email protected]>
Co-authored-by: Michael Beemer <[email protected]>

Author: 3 people

README.md

@@ -252,6 +252,8 @@ returns
 { "value": true, "reason": "TARGETING_MATCH", "variant": "off" }
 ```
 
+### [Customization of sync providers](./docs/configuration.md)
+
 ### [Reusable targeting rules](./docs/reusable_targeting_rules.md)
 
 ### [Fractional Evaluation](./docs/fractional_evaluation.md)
@@ -261,3 +263,4 @@ returns
 <a href="https://github.com/open-feature/flagd/graphs/contributors">
   <img src="https://contrib.rocks/image?repo=open-feature/flagd" />
 </a>
+

cmd/root.go

@@ -13,6 +13,7 @@ var (
 	Version string
 	Commit  string
 	Date    string
+	Debug   bool
 )
 
 var rootCmd = &cobra.Command{
@@ -45,7 +46,7 @@ func init() {
 	// Here you will define your flags and configuration settings.
 	// Cobra supports persistent flags, which, if defined here,
 	// will be global for your application.
-
+	rootCmd.PersistentFlags().BoolVarP(&Debug, "debug", "x", false, "verbose logging")
 	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.agent.yaml)")
 }
 

cmd/start.go

@@ -15,6 +15,7 @@ const (
 	serviceProviderFlagName = "service-provider"
 	socketPathFlagName      = "socket-path"
 	syncProviderFlagName    = "sync-provider"
+	providerArgsFlagName    = "sync-provider-args"
 	evaluatorFlagName       = "evaluator"
 	serverCertPathFlagName  = "server-cert-path"
 	serverKeyPathFlagName   = "server-key-path"
@@ -40,6 +41,8 @@ func init() {
 	flags.StringP(evaluatorFlagName, "e", "json", "Set an evaluator e.g. json")
 	flags.StringP(serverCertPathFlagName, "c", "", "Server side tls certificate path")
 	flags.StringP(serverKeyPathFlagName, "k", "", "Server side tls key path")
+	flags.StringToStringP(providerArgsFlagName,
+		"a", nil, "Sync provider arguments as key values separated by =")
 	flags.StringSliceP(
 		uriFlagName, "f", []string{}, "Set a sync provider uri to read data from this can be a filepath or url. "+
 			"Using multiple providers is supported where collisions between "+
@@ -51,13 +54,12 @@ func init() {
 	_ = viper.BindPFlag(socketPathFlagName, flags.Lookup(socketPathFlagName))
 	_ = viper.BindPFlag(serviceProviderFlagName, flags.Lookup(serviceProviderFlagName))
 	_ = viper.BindPFlag(syncProviderFlagName, flags.Lookup(syncProviderFlagName))
+	_ = viper.BindPFlag(providerArgsFlagName, flags.Lookup(providerArgsFlagName))
 	_ = viper.BindPFlag(evaluatorFlagName, flags.Lookup(evaluatorFlagName))
 	_ = viper.BindPFlag(serverCertPathFlagName, flags.Lookup(serverCertPathFlagName))
 	_ = viper.BindPFlag(serverKeyPathFlagName, flags.Lookup(serverKeyPathFlagName))
 	_ = viper.BindPFlag(uriFlagName, flags.Lookup(uriFlagName))
 	_ = viper.BindPFlag(bearerTokenFlagName, flags.Lookup(bearerTokenFlagName))
-
-	_ = startCmd.MarkFlagRequired("uri")
 }
 
 // startCmd represents the start command
@@ -69,8 +71,11 @@ var startCmd = &cobra.Command{
 		// Configure loggers -------------------------------------------------------
 		log.SetFormatter(&log.JSONFormatter{})
 		log.SetOutput(os.Stdout)
-		log.SetLevel(log.DebugLevel)
-
+		if Debug {
+			log.SetLevel(log.DebugLevel)
+		} else {
+			log.SetLevel(log.InfoLevel)
+		}
 		// Build Runtime -----------------------------------------------------------
 		rt, err := runtime.FromConfig(runtime.Config{
 			ServiceProvider:   viper.GetString(serviceProviderFlagName),
@@ -80,6 +85,7 @@ var startCmd = &cobra.Command{
 			ServiceKeyPath:    viper.GetString(serverKeyPathFlagName),
 
 			SyncProvider:    viper.GetString(syncProviderFlagName),
+			ProviderArgs:    viper.GetStringMapString(providerArgsFlagName),
 			SyncURI:         viper.GetStringSlice(uriFlagName),
 			SyncBearerToken: viper.GetString(bearerTokenFlagName),
 

docs/configuration.md

@@ -13,6 +13,7 @@ Supported flags are as follows (result of running `./flagd start --help`):
   -c, --server-cert-path string   Server side tls certificate path
   -k, --server-key-path string    Server side tls key path
   -s, --service-provider string   Set a service provider e.g. http or grpc (default "http")
+  -a, --sync-provider-args        Sync provider arguments as key values separated by =
   -d, --socket-path string        Set the flagd socket path. With grpc the service will become available on this address. With http(s) the grpc-gateway proxy will use this address internally
   -y, --sync-provider string      Set a sync provider e.g. filepath or remote (default "filepath")
   -f, --uri strings               Set a sync provider uri to read data from this can be a filepath or url. Using multiple providers is supported where collisions between flags with the same key, the later will be used.
@@ -22,3 +23,25 @@ Environment variable keys are uppercased, prefixed with `FLAGD_` and all `-` are
 `sync-provider` in environment variable form is `FLAGD_SYNC_PROVIDER`.
 
 Config file expects the keys to have the exact naming as the flags.
+
+
+### Customising sync providers
+
+Custom sync providers can be used to provide flag evaluation logic.
+
+#### Kubernetes provider 
+
+The Kubernetes provider allows flagD to connect to a Kubernetes cluster and evaluate flags against a specified FeatureFlagConfiguration resource as defined within the [open-feature-operator](https://github.com/open-feature/open-feature-operator/blob/main/apis/core/v1alpha1/featureflagconfiguration_types.go) spec.
+
+To use an existing FeatureFlagConfiguration custom resource, start flagD with the following command:
+
+```shell
+flagd start --sync-provider=kubernetes --sync-provider-args=featureflagconfiguration=my-example --sync-provider-args=namespace=default
+```
+
+An additional optional flag `refreshtime` can be applied to shorten the cache refresh when using the Kubernetes provider ( The default is 5s ). As an example: 
+
+```shell
+flagd start --sync-provider=kubernetes --sync-provider-args=featureflagconfiguration=my-example --sync-provider-args=namespace=default
+--sync-provider-args=refreshtime=1s
+```

go.mod

@@ -11,7 +11,8 @@ require (
 	github.com/golang/mock v1.6.0
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.11.1
 	github.com/mattn/go-colorable v0.1.12
-	github.com/open-feature/schemas v0.0.0-20220809125026-ba7ea0aa4841
+	github.com/open-feature/open-feature-operator v0.0.10-0.20220826061622-a6421d66936a
+	github.com/open-feature/schemas v0.0.0-20220809125333-185e3bd77775
 	github.com/robfig/cron v1.2.0
 	github.com/sirupsen/logrus v1.8.1
 	github.com/soheilhy/cmux v0.1.5
@@ -24,25 +25,46 @@ require (
 	golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f
 	google.golang.org/grpc v1.48.0
 	google.golang.org/protobuf v1.28.1
+	k8s.io/apimachinery v0.25.0
+	k8s.io/client-go v0.25.0
+	sigs.k8s.io/controller-runtime v0.11.0
 )
 
-require gopkg.in/yaml.v2 v2.4.0 // indirect
-
 require (
+	github.com/PuerkitoBio/purell v1.1.1 // indirect
+	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
 	github.com/common-nighthawk/go-figure v0.0.0-20200609044655-c4b36f998cf2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/emicklei/go-restful/v3 v3.8.0 // indirect
+	github.com/evanphx/json-patch v4.12.0+incompatible // indirect
+	github.com/go-logr/logr v1.2.3 // indirect
+	github.com/go-openapi/jsonpointer v0.19.5 // indirect
+	github.com/go-openapi/jsonreference v0.19.5 // indirect
+	github.com/go-openapi/swag v0.21.1 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/gnostic v0.5.7-v3refs // indirect
+	github.com/google/go-cmp v0.5.8 // indirect
+	github.com/google/gofuzz v1.1.0 // indirect
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
+	github.com/imdario/mergo v0.3.12 // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
 	github.com/magiconair/properties v1.8.6 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pelletier/go-toml v1.9.5 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/afero v1.8.2 // indirect
 	github.com/spf13/cast v1.5.0 // indirect
@@ -51,10 +73,23 @@ require (
 	github.com/subosito/gotenv v1.3.0 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
-	golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e // indirect
-	golang.org/x/sys v0.0.0-20220615213510-4f61da869c0c // indirect
+	golang.org/x/net v0.0.0-20220722155237-a158d28d115b // indirect
+	golang.org/x/oauth2 v0.0.0-20220722155238-128564f6959c // indirect
+	golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f // indirect
+	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 // indirect
 	golang.org/x/text v0.3.7 // indirect
+	golang.org/x/time v0.0.0-20220411224347-583f2d630306 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
 	google.golang.org/genproto v0.0.0-20220728213248-dd149ef739b9 // indirect
+	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/ini.v1 v1.66.4 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/api v0.25.0 // indirect
+	k8s.io/klog/v2 v2.70.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20220803162953-67bda5d908f1 // indirect
+	k8s.io/utils v0.0.0-20220728103510-ee6ede2d64ed // indirect
+	sigs.k8s.io/json v0.0.0-20220713155537-f223a00ba0e2 // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
+	sigs.k8s.io/yaml v1.3.0 // indirect
 )