add post-flush reheat action

app/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"log"
+	"net/http"
 	"os"
 	"time"
 
@@ -101,10 +102,19 @@ func main() {
 		Admins:        opts.Admins,
 		DevMode:       opts.DevMode,
 		Exporter:      &exporter,
-		Cache:         common.NewLoadingCache(4*time.Hour, 15*time.Minute),
 		AuthProviders: makeAuthProviders(sessionStore),
 	}
 
+	srv.Cache = common.NewLoadingCache(4*time.Hour, 15*time.Minute, func() {
+		// set post-flush callback
+		resp, err := http.Get(opts.RemarkURL + "/api/v1/list")
+		if err != nil {
+			log.Printf("[WARN] failed to refresh cached list, %s", err)
+			return
+		}
+		resp.Body.Close()
+	})
+
 	if opts.DevMode {
 		log.Printf("[WARN] running in dev mode, no auth!")
 	}

app/rest/common/cache.go

@@ -15,12 +15,13 @@ type LoadingCache interface {
 
 // loadingCache implements LoadingCache interface on top of cache.Cache
 type loadingCache struct {
-	bytesCache *cache.Cache
+	bytesCache  *cache.Cache
+	postFlushFn func()
 }
 
 // NewLoadingCache makes loadingCache implementation
-func NewLoadingCache(defaultExpiration, cleanupInterval time.Duration) LoadingCache {
-	return &loadingCache{bytesCache: cache.New(defaultExpiration, cleanupInterval)}
+func NewLoadingCache(defaultExpiration, cleanupInterval time.Duration, postFlushFn func()) LoadingCache {
+	return &loadingCache{bytesCache: cache.New(defaultExpiration, cleanupInterval), postFlushFn: postFlushFn}
 }
 
 func (lc *loadingCache) Get(key string, ttl time.Duration, fn func() ([]byte, error)) (data []byte, err error) {
@@ -39,4 +40,7 @@ func (lc *loadingCache) Get(key string, ttl time.Duration, fn func() ([]byte, er
 
 func (lc *loadingCache) Flush() {
 	lc.bytesCache.Flush()
+	if lc.postFlushFn != nil {
+		lc.postFlushFn()
+	}
 }