feat: Add rate limit (#21)

README.md

@@ -57,6 +57,7 @@ Starts the indexer service, which includes the fetcher and JSON-RPC server
 
 FLAGS
  -db-path indexer-db the absolute path for the indexer DB (embedded)
+ -http-rate-limit 0 the maximum HTTP requests allowed per minute per IP, unlimited by default
  -listen-address 0.0.0.0:8546 the IP:PORT URL for the indexer JSON-RPC server
  -log-level info the log level for the CLI output
  -max-chunk-size 100 the range for fetching blockchain data by a single worker

cmd/start.go

@@ -5,8 +5,11 @@ import (
  "errors"
  "flag"
  "fmt"
+ "net/http"
+ "time"
 
  "github.com/go-chi/chi/v5"
+ "github.com/go-chi/httprate"
  "github.com/peterbourgon/ff/v3/ffcli"
  "go.uber.org/zap"
 
@@ -31,6 +34,8 @@ type startCfg struct {
 
  maxSlots int
  maxChunkSize int64
+
+ rateLimit int
 }
 
 // newStartCmd creates the indexer start command
@@ -95,6 +100,13 @@ func (c *startCfg) registerFlags(fs *flag.FlagSet) {
  fetch.DefaultMaxChunkSize,
  "the range for fetching blockchain data by a single worker",
  )
+
+ fs.IntVar(
+ &c.rateLimit,
+ "http-rate-limit",
+ 0,
+ "the maximum HTTP requests allowed per minute per IP, unlimited by default",
+ )
 }
 
 // exec executes the indexer start command
@@ -149,6 +161,24 @@ func (c *startCfg) exec(ctx context.Context) error {
  )
 
  mux := chi.NewMux()
+
+ if c.rateLimit != 0 {
+ logger.Info("rate-limit set", zap.Int("rate-limit", c.rateLimit))
+ mux.Use(httprate.Limit(
+ c.rateLimit,
+ 1*time.Minute,
+ httprate.WithKeyFuncs(httprate.KeyByRealIP),
+ httprate.WithLimitHandler(func(w http.ResponseWriter, r *http.Request) {
+ //nolint:errcheck // no need to handle error here, it had been checked before
+ ip, _ := httprate.KeyByRealIP(r)
+ logger.Debug("too many requests", zap.String("from", ip))
+
+ // send a json response to give more info when using the graphQL explorer
+ http.Error(w, `{"error": "too many requests"}`, http.StatusTooManyRequests)
+ }),
+ ))
+ }
+
  mux = j.SetupRoutes(mux)
  mux = graph.Setup(db, em, mux)
 

go.mod

@@ -80,6 +80,7 @@ require (
  github.com/decred/dcrd/dcrec/secp256k1/v4 v4.2.0 // indirect
  github.com/gnolang/gno v0.0.0-20231215125729-9262c1a8f949
  github.com/gnolang/overflow v0.0.0-20170615021017-4d914c927216 // indirect
+ github.com/go-chi/httprate v0.9.0
  golang.org/x/crypto v0.21.0 // indirect
  google.golang.org/protobuf v1.33.0 // indirect
 )

go.sum

@@ -112,6 +112,8 @@ github.com/gnolang/overflow v0.0.0-20170615021017-4d914c927216 h1:GKvsK3oLWG9B1G
 github.com/gnolang/overflow v0.0.0-20170615021017-4d914c927216/go.mod h1:xJhtEL7ahjM1WJipt89gel8tHzfIl/LyMY+lCYh38d8=
 github.com/go-chi/chi/v5 v5.0.12 h1:9euLV5sTrTNTRUU9POmDUvfxyj6LAABLUcEWO+JJb4s=
 github.com/go-chi/chi/v5 v5.0.12/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
+github.com/go-chi/httprate v0.9.0 h1:21A+4WDMDA5FyWcg7mNrhj63aNT8CGh+Z1alOE/piU8=
+github.com/go-chi/httprate v0.9.0/go.mod h1:6GOYBSwnpra4CQfAKXu8sQZg+nZ0M1g9QnyFvxrAB8A=
 github.com/go-errors/errors v1.4.2 h1:J6MZopCL4uSllY1OfXM374weqZFFItUbrImctkmUxIA=
 github.com/go-errors/errors v1.4.2/go.mod h1:sIVyrIiJhuEF+Pj9Ebtd6P/rEYROXFi3BopGUQ5a5Og=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=