/
main.go
247 lines (216 loc) · 5.38 KB
/
main.go
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package main
import (
"bytes"
"context"
"flag"
"fmt"
"io/ioutil"
"net"
"net/http"
"net/http/httputil"
"net/url"
"os"
"os/signal"
"strconv"
"sync"
"time"
"github.com/gorilla/mux"
"github.com/jshufro/beacon-cache-proxy/cache"
"go.uber.org/zap"
)
var logger *zap.Logger
var globalwg sync.WaitGroup
var c cache.Cache
var proxy *httputil.ReverseProxy
var cachingProxy *httputil.ReverseProxy
func initLogger(debug *bool) error {
var cfg zap.Config
var err error
if *debug {
cfg = zap.NewDevelopmentConfig()
} else {
cfg = zap.NewProductionConfig()
}
logger, err = cfg.Build()
return err
}
func onCachingProxyResponse(resp *http.Response) error {
vars := mux.Vars(resp.Request)
serialized, err := ioutil.ReadAll(resp.Body)
if err != nil {
logger.Warn("Error reading response while caching", zap.Error(err))
return nil
}
resp.Body = ioutil.NopCloser(bytes.NewReader(serialized))
// Save the response asynchronously so the client is waiting
defer func() {
e, ok := vars["epoch"]
if !ok {
return
}
if _, err := strconv.ParseUint(e, 10, 64); err != nil {
// Epoch is non-numeric, skip caching
return
}
err := c.Set(e, serialized)
if err != nil {
logger.Warn("Error caching response", zap.Error(err))
}
}()
return nil
}
func cachedQuery(w http.ResponseWriter, r *http.Request) {
var cached []byte
var err error
var headers http.Header
logger.Debug("Proxying committees query", zap.String("path", r.URL.String()))
vars := mux.Vars(r)
e, ok := vars["epoch"]
if !ok {
// Epoch not found, proxy request
logger.Debug("no epoch parameter passed")
goto pass
}
if _, err := strconv.ParseUint(e, 10, 64); err != nil {
// Epoch is non-numeric, proxy request
logger.Debug("non-numeric epoch parameter passed")
goto pass
}
cached, headers, err = c.Get(r.Header, e)
if err != nil {
logger.Warn("Error querying cache", zap.Error(err))
goto pass
}
if cached != nil {
// We already have the data for this, short-circuit the proxy
for k, v := range headers {
for _, vv := range v {
w.Header().Set(k, vv)
}
}
w.WriteHeader(http.StatusOK)
w.Write(cached)
logger.Debug("cache hit", zap.String("epoch", e), zap.String("Content-Type", w.Header().Get("Content-Type")))
return
}
// We don't have the data, so proxy now
pass:
cachingProxy.ServeHTTP(w, r)
}
func serve(listener net.Listener) http.Server {
server := http.Server{}
router := mux.NewRouter()
router.Path("/eth/v1/beacon/states/head/committees").
Queries("epoch", "{epoch}").
HandlerFunc(cachedQuery)
router.PathPrefix("/").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
proxy.ServeHTTP(w, r)
})
http.Handle("/", router)
globalwg.Add(1)
go func() {
if err := server.Serve(listener); err != nil {
logger.Info("Stopping server", zap.Error(err))
globalwg.Done()
}
}()
return server
}
func prune(count uint) {
if count == 0 {
logger.Debug("pruning disabled, skipping")
return
}
logger.Debug("Pruning started", zap.Uint("retain", count))
deleted, err := c.Prune(count)
if err != nil {
logger.Warn("error pruning cache", zap.Error(err))
return
}
logger.Debug("pruned cache", zap.Uint("files", deleted))
}
func main() {
bnURLFlag := flag.String("bn-url", "", "URL to the beacon node to proxy, eg, http://0.0.0.0:5052")
addrURLFlag := flag.String("addr", "127.0.0.1:55052", "Address for the proxy to listen on")
dataDirFlag := flag.String("data-dir", "/tmp/treegen-proxy", "Path in which to save cache data")
retain := flag.Uint("retain", 7000, "Number of epochs to retain in the cache")
debug := flag.Bool("debug", false, "Whether to enable debug logging")
conv := flag.String("conv", "", "File to convert to pb")
flag.Parse()
if *conv != "" {
err := cache.Conv(*conv)
if err != nil {
panic(err)
}
return
}
if *bnURLFlag == "" {
fmt.Fprintf(os.Stderr, "Invalid -bn-url:\n")
flag.PrintDefaults()
os.Exit(1)
}
if err := initLogger(debug); err != nil {
fmt.Fprintf(os.Stderr, "Error initializing logger: %v\n", err)
os.Exit(1)
}
defer logger.Sync()
base, err := url.Parse(*bnURLFlag)
if err != nil {
fmt.Fprintf(os.Stderr, "Invalid -bn-url: %v\n", err)
os.Exit(1)
}
logger.Debug("Parsed -bn-url", zap.String("url", *bnURLFlag))
// Init the cache
c, err = cache.NewDiskCache(*dataDirFlag)
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to initialize cache: %v\n", err)
os.Exit(1)
}
ticker := time.NewTicker(60 * time.Minute)
done := make(chan bool, 1)
// Set up the periodic prune
go func() {
// Prune on startup
prune(*retain)
for {
select {
case <-done:
return
case <-ticker.C:
prune(*retain)
continue
}
}
}()
// Set up the reverse proxy
proxy = httputil.NewSingleHostReverseProxy(base)
cachingProxy = httputil.NewSingleHostReverseProxy(base)
cachingProxy.ModifyResponse = onCachingProxyResponse
// Set up the webserver
listener, err := net.Listen("tcp", *addrURLFlag)
if err != nil {
logger.Fatal("error starting webserver", zap.Error(err))
}
server := serve(listener)
// Set up the tickler to keep the cache warm
tickler := tickler{
c: c,
proxy: cachingProxy,
logger: logger,
}
tickler.start()
// Wait for signals
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt)
<-c
signal.Reset()
close(c)
ticker.Stop()
done <- true
close(done)
tickler.stop()
server.Shutdown(context.Background())
listener.Close()
globalwg.Wait()
logger.Debug("Bye")
}