feat: implement rate limiter for the grid-proxy

Signed-off-by: nabil salah <nabil.salah203@gmail.com>

Author: Nabil-Salah

grid-proxy/Makefile

@@ -58,6 +58,7 @@ server-start: ## Start the proxy server			(Args: `m=<MNEMONICS>`)
 		--postgres-db tfgrid-graphql \
 		--postgres-password postgres \
 		--postgres-user postgres \
+		--rate-limit-rps 1000 \
 		--mnemonics "$(m)" ;
 
 all-start: db-stop db-start sleep db-fill server-start ## Full start of the database and the server (Args: `m=<MNEMONICS>`)

grid-proxy/cmds/proxy_server/main.go

@@ -55,6 +55,7 @@ type flags struct {
 	relayURL               string
 	mnemonics              string
 	maxPoolOpenConnections int
+	rateLimitRPS           int // Rate limit requests per second per IP
 
 	noIndexer                       bool // true to stop the indexer, useful on running for testing
 	indexerUpserterBatchSize        uint
@@ -98,6 +99,7 @@ func main() {
 	flag.StringVar(&f.relayURL, "relay-url", DefaultRelayURL, "RMB relay url")
 	flag.StringVar(&f.mnemonics, "mnemonics", "", "Dummy user mnemonics for relay calls")
 	flag.IntVar(&f.maxPoolOpenConnections, "max-open-conns", 80, "max number of db connection pool open connections")
+	flag.IntVar(&f.rateLimitRPS, "rate-limit-rps", 20, "rate limit requests per second per IP address (0 to disable)")
 
 	flag.BoolVar(&f.noIndexer, "no-indexer", false, "do not start the indexer")
 	flag.UintVar(&f.indexerUpserterBatchSize, "indexer-upserter-batch-size", 20, "results batch size which collected before upserting")
@@ -182,6 +184,13 @@ func main() {
 		log.Fatal().Err(err).Msg("failed to create mux server")
 	}
 
+	// Log rate limiting configuration
+	if f.rateLimitRPS > 0 {
+		log.Info().Int("rate_limit_rps", f.rateLimitRPS).Msg("HTTP rate limiting enabled")
+	} else {
+		log.Info().Msg("HTTP rate limiting disabled")
+	}
+
 	if err := app(s, f); err != nil {
 		log.Fatal().Msg(err.Error())
 	}
@@ -331,7 +340,7 @@ func createServer(f flags, dbClient explorer.DBClient, gitCommit string, relayCl
 	router := mux.NewRouter().StrictSlash(true)
 
 	// setup explorer
-	if err := explorer.Setup(router, gitCommit, dbClient, relayClient, idxIntervals); err != nil {
+	if err := explorer.Setup(router, gitCommit, dbClient, relayClient, idxIntervals, f.rateLimitRPS); err != nil {
 		return nil, err
 	}
 

grid-proxy/internal/explorer/mw/ratelimiter.go

@@ -0,0 +1,96 @@
+package mw
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/rs/zerolog/log"
+	"github.com/threefoldtech/tfgrid-sdk-go/grid-proxy/tools/ratelimiter"
+)
+
+// RateLimiterMiddleware wraps the rate limiter to work with the existing middleware pattern
+type RateLimiterMiddleware struct {
+	limiter *ratelimiter.SlidingWindowRateLimiter
+}
+
+// NewRateLimiterMiddleware creates a new rate limiter middleware
+func NewRateLimiterMiddleware(ratePerSecond int) *RateLimiterMiddleware {
+	return &RateLimiterMiddleware{
+		limiter: ratelimiter.NewSlidingWindowRateLimiter(ratePerSecond),
+	}
+}
+
+// RateLimitAction wraps an Action with rate limiting
+func (rlm *RateLimiterMiddleware) RateLimitAction(action Action) Action {
+	return func(r *http.Request) (interface{}, Response) {
+		clientIP := ratelimiter.GetClientIP(r)
+
+		if !rlm.limiter.Allow(clientIP) {
+			log.Warn().
+				Str("ip", clientIP).
+				Str("method", r.Method).
+				Str("path", r.URL.Path).
+				Msg("Rate limit exceeded")
+
+			return nil, rlm.TooManyRequests(fmt.Errorf("rate limit exceeded for IP: %s", clientIP), clientIP)
+		}
+
+		return action(r)
+	}
+}
+
+// RateLimitProxyAction wraps a ProxyAction with rate limiting
+func (rlm *RateLimiterMiddleware) RateLimitProxyAction(action ProxyAction) ProxyAction {
+	return func(r *http.Request) (*http.Response, Response) {
+		// Get client IP
+		clientIP := ratelimiter.GetClientIP(r)
+
+		// Check rate limit
+		if !rlm.limiter.Allow(clientIP) {
+			log.Warn().
+				Str("ip", clientIP).
+				Str("method", r.Method).
+				Str("path", r.URL.Path).
+				Msg("Rate limit exceeded")
+
+			return nil, rlm.TooManyRequests(fmt.Errorf("rate limit exceeded for IP: %s", clientIP), clientIP)
+		}
+
+		// Rate limit passed, execute the original action
+		return action(r)
+	}
+}
+
+// AsRateLimitedHandlerFunc wraps AsHandlerFunc with rate limiting
+func (rlm *RateLimiterMiddleware) AsRateLimitedHandlerFunc(action Action) http.HandlerFunc {
+	rateLimitedAction := rlm.RateLimitAction(action)
+	return AsHandlerFunc(rateLimitedAction)
+}
+
+// AsRateLimitedProxyHandlerFunc wraps AsProxyHandlerFunc with rate limiting
+func (rlm *RateLimiterMiddleware) AsRateLimitedProxyHandlerFunc(action ProxyAction) http.HandlerFunc {
+	rateLimitedAction := rlm.RateLimitProxyAction(action)
+	return AsProxyHandlerFunc(rateLimitedAction)
+}
+
+// GetStats returns rate limiter statistics
+func (rlm *RateLimiterMiddleware) GetStats() map[string]interface{} {
+	return rlm.limiter.GetStats()
+}
+
+// TooManyRequests returns a 429 Too Many Requests response with accurate rate limit headers
+func (rlm *RateLimiterMiddleware) TooManyRequests(err error, clientIP string) Response {
+	rateLimit := rlm.limiter.GetRateLimit()
+	currentRequests := rlm.limiter.GetCurrentRequestCount(clientIP)
+	remaining := max(0, rateLimit-currentRequests)
+	resetTime := time.Now().Add(time.Second)
+
+	return Error(err, http.StatusTooManyRequests).
+		WithHeader("Retry-After", "1").
+		WithHeader("X-RateLimit-Limit", strconv.Itoa(rateLimit)).
+		WithHeader("X-RateLimit-Remaining", strconv.Itoa(remaining)).
+		WithHeader("X-RateLimit-Reset", strconv.FormatInt(resetTime.Unix(), 10)).
+		WithHeader("X-Client-IP", clientIP)
+}

grid-proxy/internal/explorer/mw/utils.go

@@ -0,0 +1,23 @@
+package mw
+
+import "net/http"
+
+// WithRateLimit wraps an Action with rate limiting if a rate limiter is provided.
+// If rateLimiter is nil, it falls back to the standard AsHandlerFunc wrapper.
+// This provides a clean way to conditionally apply rate limiting to endpoints.
+func WithRateLimit(rateLimiter *RateLimiterMiddleware, action Action) http.HandlerFunc {
+	if rateLimiter != nil {
+		return rateLimiter.AsRateLimitedHandlerFunc(action)
+	}
+	return AsHandlerFunc(action)
+}
+
+// WithRateLimitProxy wraps a ProxyAction with rate limiting if a rate limiter is provided.
+// If rateLimiter is nil, it falls back to the standard AsProxyHandlerFunc wrapper.
+// This provides a clean way to conditionally apply rate limiting to proxy endpoints.
+func WithRateLimitProxy(rateLimiter *RateLimiterMiddleware, action ProxyAction) http.HandlerFunc {
+	if rateLimiter != nil {
+		return rateLimiter.AsRateLimitedProxyHandlerFunc(action)
+	}
+	return AsProxyHandlerFunc(action)
+}

grid-proxy/internal/explorer/server.go

@@ -629,7 +629,7 @@ func (a *App) getContractBills(r *http.Request) (interface{}, mw.Response) {
 // @license.name Apache 2.0
 // @license.url http://www.apache.org/licenses/LICENSE-2.0.html
 // @BasePath /
-func Setup(router *mux.Router, gitCommit string, cl DBClient, relayClient rmb.Client, idxIntervals map[string]uint) error {
+func Setup(router *mux.Router, gitCommit string, cl DBClient, relayClient rmb.Client, idxIntervals map[string]uint, rateLimitRPS int) error {
 
 	a := App{
 		cl:             cl,
@@ -638,32 +638,41 @@ func Setup(router *mux.Router, gitCommit string, cl DBClient, relayClient rmb.Cl
 		idxIntervals:   idxIntervals,
 	}
 
-	router.HandleFunc("/farms", mw.AsHandlerFunc(a.listFarms))
-	router.HandleFunc("/stats", mw.AsHandlerFunc(a.getStats))
+	// Create rate limiter middleware if rate limiting is enabled
+	var rateLimiter *mw.RateLimiterMiddleware
+	if rateLimitRPS > 0 {
+		rateLimiter = mw.NewRateLimiterMiddleware(rateLimitRPS)
+		log.Info().Int("rate_limit_rps", rateLimitRPS).Msg("Rate limiting enabled")
+	} else {
+		log.Info().Msg("Rate limiting disabled")
+	}
+
+	router.HandleFunc("/farms", mw.WithRateLimit(rateLimiter, a.listFarms))
+	router.HandleFunc("/stats", mw.WithRateLimit(rateLimiter, a.getStats))
 
-	router.HandleFunc("/twins", mw.AsHandlerFunc(a.listTwins))
-	router.HandleFunc("/twins/{twin_id:[0-9]+}/consumption", mw.AsHandlerFunc(a.getTwinConsumption))
+	router.HandleFunc("/twins", mw.WithRateLimit(rateLimiter, a.listTwins))
+	router.HandleFunc("/twins/{twin_id:[0-9]+}/consumption", mw.WithRateLimit(rateLimiter, a.getTwinConsumption))
 
-	router.HandleFunc("/nodes", mw.AsHandlerFunc(a.getNodes))
-	router.HandleFunc("/nodes/{node_id:[0-9]+}", mw.AsHandlerFunc(a.getNode))
-	router.HandleFunc("/nodes/{node_id:[0-9]+}/status", mw.AsHandlerFunc(a.getNodeStatus))
-	router.HandleFunc("/nodes/{node_id:[0-9]+}/statistics", mw.AsHandlerFunc(a.getNodeStatistics))
-	router.HandleFunc("/nodes/{node_id:[0-9]+}/gpu", mw.AsHandlerFunc(a.getNodeGpus))
+	router.HandleFunc("/nodes", mw.WithRateLimit(rateLimiter, a.getNodes))
+	router.HandleFunc("/nodes/{node_id:[0-9]+}", mw.WithRateLimit(rateLimiter, a.getNode))
+	router.HandleFunc("/nodes/{node_id:[0-9]+}/status", mw.WithRateLimit(rateLimiter, a.getNodeStatus))
+	router.HandleFunc("/nodes/{node_id:[0-9]+}/statistics", mw.WithRateLimit(rateLimiter, a.getNodeStatistics))
+	router.HandleFunc("/nodes/{node_id:[0-9]+}/gpu", mw.WithRateLimit(rateLimiter, a.getNodeGpus))
 
-	router.HandleFunc("/gateways", mw.AsHandlerFunc(a.getGateways))
-	router.HandleFunc("/gateways/{node_id:[0-9]+}", mw.AsHandlerFunc(a.getGateway))
-	router.HandleFunc("/gateways/{node_id:[0-9]+}/status", mw.AsHandlerFunc(a.getNodeStatus))
+	router.HandleFunc("/gateways", mw.WithRateLimit(rateLimiter, a.getGateways))
+	router.HandleFunc("/gateways/{node_id:[0-9]+}", mw.WithRateLimit(rateLimiter, a.getGateway))
+	router.HandleFunc("/gateways/{node_id:[0-9]+}/status", mw.WithRateLimit(rateLimiter, a.getNodeStatus))
 
-	router.HandleFunc("/contracts", mw.AsHandlerFunc(a.listContracts))
-	router.HandleFunc("/contracts/{contract_id:[0-9]+}", mw.AsHandlerFunc(a.getContract))
-	router.HandleFunc("/contracts/{contract_id:[0-9]+}/bills", mw.AsHandlerFunc(a.getContractBills))
+	router.HandleFunc("/contracts", mw.WithRateLimit(rateLimiter, a.listContracts))
+	router.HandleFunc("/contracts/{contract_id:[0-9]+}", mw.WithRateLimit(rateLimiter, a.getContract))
+	router.HandleFunc("/contracts/{contract_id:[0-9]+}/bills", mw.WithRateLimit(rateLimiter, a.getContractBills))
 
-	router.HandleFunc("/public_ips", mw.AsHandlerFunc(a.GetPublicIps))
+	router.HandleFunc("/public_ips", mw.WithRateLimit(rateLimiter, a.GetPublicIps))
 
-	router.HandleFunc("/", mw.AsHandlerFunc(a.indexPage(router)))
-	router.HandleFunc("/ping", mw.AsHandlerFunc(a.ping))
-	router.HandleFunc("/version", mw.AsHandlerFunc(a.version))
-	router.HandleFunc("/health", mw.AsHandlerFunc(a.health))
+	router.HandleFunc("/", mw.WithRateLimit(rateLimiter, a.indexPage(router)))
+	router.HandleFunc("/ping", mw.WithRateLimit(rateLimiter, a.ping))
+	router.HandleFunc("/version", mw.WithRateLimit(rateLimiter, a.version))
+	router.HandleFunc("/health", mw.WithRateLimit(rateLimiter, a.health))
 	router.PathPrefix("/swagger/").Handler(httpSwagger.WrapHandler)
 
 	return nil

grid-proxy/tools/ratelimiter/README.md

@@ -0,0 +1,83 @@
+# Rate Limiter
+
+This package implements a sliding window rate limiter for the TFGrid Proxy server.
+
+## Features
+
+- **IP-based Rate Limiting**: Tracks requests per IP address
+- **Sliding Window Algorithm**: Uses a sliding window approach for smooth rate limiting
+- **Thread-Safe**: Safe for concurrent use across multiple goroutines
+- **Memory Efficient**: Automatic cleanup of old entries
+- **Configurable**: Rate limit can be set via command-line flag
+
+## Usage
+
+### Command Line Flag
+
+Use the `--rate-limit-rps` flag to set the rate limit:
+
+```bash
+# Enable rate limiting at 20 requests per second per IP (default)
+./proxy_server --rate-limit-rps 20
+
+# Set custom rate limit of 100 requests per second per IP
+./proxy_server --rate-limit-rps 100
+
+# Disable rate limiting
+./proxy_server --rate-limit-rps 0
+```
+
+### IP Address Detection
+
+The rate limiter automatically extracts the client IP address using the following priority:
+
+1. `X-Real-IP` header
+2. `X-Forwarded-For` header (first IP if multiple)
+3. `RemoteAddr` from the connection
+
+This ensures proper rate limiting even when the proxy is behind load balancers or CDNs.
+
+### HTTP Response
+
+When rate limit is exceeded, the server returns:
+
+- **Status Code**: 429 (Too Many Requests)
+- **Headers**:
+  - `Retry-After: 1` - Suggests retrying after 1 second
+  - `X-RateLimit-Limit: 20` - Current rate limit
+  - `X-RateLimit-Remaining: 0` - Remaining requests (0 when exceeded)
+
+### Algorithm Details
+
+The sliding window algorithm works as follows:
+
+1. **Time Window**: Uses a 1-second sliding window
+2. **Request Tracking**: Stores timestamps of requests within the window
+3. **Cleanup**: Automatically removes requests older than the window
+4. **Memory Management**: Periodically cleans up inactive IP entries
+
+### Performance
+
+- **Memory Usage**: Minimal overhead, only stores active IP addresses
+- **CPU Usage**: O(n) where n is the number of requests in the current window
+- **Concurrency**: Thread-safe with read-write mutexes for optimal performance
+
+## Configuration
+
+| Flag | Default | Description |
+|------|---------|-------------|
+| `--rate-limit-rps` | 20 | Requests per second per IP address (0 to disable) |
+
+## Logging
+
+The rate limiter provides debug logging for:
+
+- Rate limit violations (WARN level)
+- New IP tracking (DEBUG level)
+- Request allowances (DEBUG level)
+- Cleanup operations (DEBUG level)
+
+Example log output:
+```
+{"level":"warn","ip":"192.168.1.100","method":"GET","path":"/nodes","time":"2025-07-07T14:40:43Z","message":"Rate limit exceeded"}
+```

grid-proxy/tools/ratelimiter/ip_utils.go

@@ -0,0 +1,26 @@
+package ratelimiter
+
+import (
+	"net"
+	"net/http"
+	"strings"
+)
+
+// GetClientIP extracts the real client IP from the HTTP request
+// It checks X-Forwarded-For, X-Real-IP headers, and falls back to RemoteAddr
+func GetClientIP(r *http.Request) string {
+	if realIP := r.Header.Get("X-Real-IP"); realIP != "" {
+		return realIP
+	}
+
+	if fwd := r.Header.Get("X-Forwarded-For"); fwd != "" {
+		parts := strings.Split(fwd, ",")
+		return strings.TrimSpace(parts[0])
+	}
+
+	host, _, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+		return r.RemoteAddr
+	}
+	return host
+}