[proxy] add experimental flag let configcat proxy always serve config from configmap (#17095)

* [proxy] add experimental flag let configcat proxy always serve config from configmap

* use etag

* Update components/proxy/plugins/configcat/configcat.go

Co-authored-by: Filip Troníček <[email protected]>

* Fix warnings and add a notice

* use `CONFIGCAT_DIR`

---------

Co-authored-by: Filip Troníček <[email protected]>

Author: iQQBot

components/proxy/plugins/configcat/configcat.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"os"
+	"path"
 	"regexp"
 	"strings"
 	"sync"
@@ -49,6 +50,8 @@ type ConfigCat struct {
 	// pollInterval sets after how much time a configuration is considered stale.
 	pollInterval time.Duration
 
+	configCatConfigDir string
+
 	configCache map[string]*configCache
 	m           sync.RWMutex
 
@@ -64,19 +67,44 @@ func (ConfigCat) CaddyModule() caddy.ModuleInfo {
 	}
 }
 
+func (c *ConfigCat) ServeFromFile(w http.ResponseWriter, r *http.Request, fileName string) {
+	fp := path.Join(c.configCatConfigDir, fileName)
+	d, err := os.Stat(fp)
+	if err != nil {
+		// This should only happen before deploying the FF resource, and logging would not be helpful, hence we can fallback to the default values.
+		_, _ = w.Write(DefaultConfig)
+		return
+	}
+	requestEtag := r.Header.Get("If-None-Match")
+	etag := fmt.Sprintf(`W/"%x-%x"`, d.ModTime().Unix(), d.Size())
+	if requestEtag != "" && requestEtag == etag {
+		w.WriteHeader(http.StatusNotModified)
+		return
+	}
+	w.Header().Set("ETag", etag)
+	http.ServeFile(w, r, fp)
+}
+
 // ServeHTTP implements caddyhttp.MiddlewareHandler.
 func (c *ConfigCat) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
 	if !pathRegex.MatchString(r.URL.Path) {
 		return next.ServeHTTP(w, r)
 	}
+	arr := strings.Split(r.URL.Path, "/")
+	configVersion := arr[len(arr)-1]
+
+	if c.configCatConfigDir != "" {
+		c.ServeFromFile(w, r, configVersion)
+		return nil
+	}
+
 	w.Header().Set("Content-Type", "application/json")
 	if c.sdkKey == "" {
-		w.Write(DefaultConfig)
+		_, _ = w.Write(DefaultConfig)
 		return nil
 	}
 	etag := r.Header.Get("If-None-Match")
-	arr := strings.Split(r.URL.Path, "/")
-	configVersion := arr[len(arr)-1]
+
 	config := c.getConfigWithCache(configVersion)
 	if etag != "" && config.hash == etag {
 		w.WriteHeader(http.StatusNotModified)
@@ -94,9 +122,14 @@ func (c *ConfigCat) Provision(ctx caddy.Context) error {
 	c.configCache = make(map[string]*configCache)
 
 	c.sdkKey = os.Getenv("CONFIGCAT_SDK_KEY")
+	c.configCatConfigDir = os.Getenv("CONFIGCAT_DIR")
 	if c.sdkKey == "" {
 		return nil
 	}
+	if c.configCatConfigDir != "" {
+		c.logger.Info("serving configcat configuration from local directory")
+		return nil
+	}
 
 	c.httpClient = &http.Client{
 		Timeout: 10 * time.Second,

install/installer/pkg/common/common.go

@@ -435,9 +435,10 @@ func ConfigcatEnv(ctx *RenderContext) []corev1.EnvVar {
 
 func ConfigcatProxyEnv(ctx *RenderContext) []corev1.EnvVar {
 	var (
-		sdkKey       string
-		baseUrl      string
-		pollInterval string
+		sdkKey        string
+		baseUrl       string
+		pollInterval  string
+		fromConfigMap string
 	)
 	_ = ctx.WithExperimental(func(cfg *experimental.Config) error {
 		if cfg.WebApp != nil && cfg.WebApp.ConfigcatKey != "" {
@@ -446,28 +447,42 @@ func ConfigcatProxyEnv(ctx *RenderContext) []corev1.EnvVar {
 		if cfg.WebApp != nil && cfg.WebApp.ProxyConfig != nil && cfg.WebApp.ProxyConfig.Configcat != nil {
 			baseUrl = cfg.WebApp.ProxyConfig.Configcat.BaseUrl
 			pollInterval = cfg.WebApp.ProxyConfig.Configcat.PollInterval
+			fromConfigMap = cfg.WebApp.ProxyConfig.Configcat.FromConfigMap
 		}
 		return nil
 	})
 
 	if sdkKey == "" {
 		return nil
 	}
-
-	return []corev1.EnvVar{
+	envs := []corev1.EnvVar{
 		{
 			Name:  "CONFIGCAT_SDK_KEY",
 			Value: sdkKey,
 		},
-		{
-			Name:  "CONFIGCAT_BASE_URL",
-			Value: baseUrl,
-		},
-		{
-			Name:  "CONFIGCAT_POLL_INTERVAL",
-			Value: pollInterval,
-		},
 	}
+
+	if fromConfigMap != "" {
+		envs = append(envs,
+			corev1.EnvVar{
+				Name:  "CONFIGCAT_DIR",
+				Value: "/data/configcat/",
+			},
+		)
+	} else {
+		envs = append(envs,
+			corev1.EnvVar{
+				Name:  "CONFIGCAT_BASE_URL",
+				Value: baseUrl,
+			},
+			corev1.EnvVar{
+				Name:  "CONFIGCAT_POLL_INTERVAL",
+				Value: pollInterval,
+			},
+		)
+	}
+
+	return envs
 }
 
 func DatabaseWaiterContainer(ctx *RenderContext) *corev1.Container {

install/installer/pkg/components/proxy/deployment.go

@@ -103,6 +103,21 @@ func deployment(ctx *common.RenderContext) ([]runtime.Object, error) {
 		if cfg.WebApp != nil && cfg.WebApp.ProxyConfig != nil {
 			frontendDevEnabled = cfg.WebApp.ProxyConfig.FrontendDevEnabled
 		}
+		if cfg.WebApp != nil && cfg.WebApp.ProxyConfig != nil && cfg.WebApp.ProxyConfig.Configcat != nil && cfg.WebApp.ProxyConfig.Configcat.FromConfigMap != "" {
+			volumes = append(volumes, corev1.Volume{
+				Name: "configcat",
+				VolumeSource: corev1.VolumeSource{
+					ConfigMap: &corev1.ConfigMapVolumeSource{
+						LocalObjectReference: corev1.LocalObjectReference{Name: cfg.WebApp.ProxyConfig.Configcat.FromConfigMap},
+						Optional:             pointer.Bool(true),
+					},
+				},
+			})
+			volumeMounts = append(volumeMounts, corev1.VolumeMount{
+				Name:      "configcat",
+				MountPath: "/data/configcat",
+			})
+		}
 		return nil
 	})
 

install/installer/pkg/config/v1/config.md

@@ -147,6 +147,7 @@ Additional config parameters that are in experimental state
 |`experimental.webapp.proxy.serviceType`||N|  |  @deprecated use components.proxy.service.serviceType instead|
 |`experimental.webapp.proxy.configcat.baseUrl`|string|N|  ||
 |`experimental.webapp.proxy.configcat.pollInterval`|string|N|  ||
+|`experimental.webapp.proxy.configcat.fromConfigMap`|string|N|  ||
 |`experimental.webapp.wsManagerBridge.skipSelf`|bool|N|  ||
 |`experimental.webapp.tracing.samplerType`|string|N| `const`, `probabilistic`, `rateLimiting`, `remote` |Values taken from https://github.com/jaegertracing/jaeger-client-go/blob/967f9c36f0fa5a2617c9a0993b03f9a3279fadc8/config/config.go#L71|
 |`experimental.webapp.tracing.samplerParam`|float64|N|  ||

install/installer/pkg/config/v1/experimental/experimental.go

@@ -287,8 +287,9 @@ type ProxyConfig struct {
 }
 
 type ConfigcatProxyConfig struct {
-	BaseUrl      string `json:"baseUrl"`
-	PollInterval string `json:"pollInterval"`
+	BaseUrl       string `json:"baseUrl"`
+	PollInterval  string `json:"pollInterval"`
+	FromConfigMap string `json:"fromConfigMap"`
 }
 
 type PublicAPIConfig struct {