This is a generic middleware to rate-limit HTTP requests.
NOTE 1: This library is considered finished.
NOTE 2: Major version changes are backward-incompatible. v2.0.0 streamlines the ugliness of the old API.
v1.0.0: This version maintains the old API but all the thirdparty modules are moved to their own repo.
v2.x.x: Brand-new API for the sake of code cleanup, thread safety, & auto-expiring data structures.
v3.x.x: Apparently we have been using golang.org/x/time/rate incorrectly. See issue #48. It always limits X number per 1 second. The time duration is not changeable, so it does not make sense to pass TTL to tollbooth.
v4.x.x: Float64 for max requests per second
v5.x.x: go.mod and go.sum
v6.x.x: Replaced go-cache with github.com/go-pkgz/expirable-cache because go-cache leaks goroutines.
v7.x.x: Replaced time/rate with embedded time/rate so that we can support more rate limit headers.
package main
import (
"net/http"
"github.com/didip/tollbooth/v7"
)
func HelloHandler(w http.ResponseWriter, req *http.Request) {
w.Write([]byte("Hello, World!"))
}
func main() {
// Create a request limiter per handler.
http.Handle("/", tollbooth.LimitFuncHandler(tollbooth.NewLimiter(1, nil), HelloHandler))
http.ListenAndServe(":12345", nil)
}-
Rate-limit by request's remote IP, path, methods, custom headers, & basic auth usernames.
import ( "time" "github.com/didip/tollbooth/v7" "github.com/didip/tollbooth/v7/limiter" ) lmt := tollbooth.NewLimiter(1, nil) // or create a limiter with expirable token buckets // This setting means: // create a 1 request/second limiter and // every token bucket in it will expire 1 hour after it was initially set. lmt = tollbooth.NewLimiter(1, &limiter.ExpirableOptions{DefaultExpirationTTL: time.Hour}) // Configure list of places to look for IP address. // By default it's: "RemoteAddr", "X-Forwarded-For", "X-Real-IP" // If your application is behind a proxy, set "X-Forwarded-For" first. lmt.SetIPLookups([]string{"RemoteAddr", "X-Forwarded-For", "X-Real-IP"}) // Limit only GET and POST requests. lmt.SetMethods([]string{"GET", "POST"}) // Limit based on basic auth usernames. // You add them on-load, or later as you handle requests. lmt.SetBasicAuthUsers([]string{"bob", "jane", "didip", "vip"}) // You can remove them later as well. lmt.RemoveBasicAuthUsers([]string{"vip"}) // Limit request headers containing certain values. // You add them on-load, or later as you handle requests. lmt.SetHeader("X-Access-Token", []string{"abc123", "xyz098"}) // You can remove all entries at once. lmt.RemoveHeader("X-Access-Token") // Or remove specific ones. lmt.RemoveHeaderEntries("X-Access-Token", []string{"limitless-token"}) // By the way, the setters are chainable. Example: lmt.SetIPLookups([]string{"RemoteAddr", "X-Forwarded-For", "X-Real-IP"}). SetMethods([]string{"GET", "POST"}). SetBasicAuthUsers([]string{"sansa"}). SetBasicAuthUsers([]string{"tyrion"})
-
Compose your own middleware by using
LimitByKeys(). -
Header entries and basic auth users can expire over time (to conserve memory).
import "time" lmt := tollbooth.NewLimiter(1, nil) // Set a custom expiration TTL for token bucket. lmt.SetTokenBucketExpirationTTL(time.Hour) // Set a custom expiration TTL for basic auth users. lmt.SetBasicAuthExpirationTTL(time.Hour) // Set a custom expiration TTL for header entries. lmt.SetHeaderEntryExpirationTTL(time.Hour)
-
Upon rejection, the following HTTP response headers are available to users:
-
X-Rate-Limit-LimitThe maximum request limit. -
X-Rate-Limit-DurationThe rate-limiter duration. -
X-Rate-Limit-Request-Forwarded-ForThe rejected requestX-Forwarded-For. -
X-Rate-Limit-Request-Remote-AddrThe rejected requestRemoteAddr.
Upon both success and rejection RateLimit headers are sent:
-
RateLimit-LimitThe maximum request limit within the time window (1s). -
RateLimit-ResetThe rate-limiter time window duration in seconds (always 1s). -
RateLimit-RemainingThe remaining tokens.
-
-
Customize your own message or function when limit is reached.
lmt := tollbooth.NewLimiter(1, nil) // Set a custom message. lmt.SetMessage("You have reached maximum request limit.") // Set a custom content-type. lmt.SetMessageContentType("text/plain; charset=utf-8") // Set a custom function for rejection. lmt.SetOnLimitReached(func(w http.ResponseWriter, r *http.Request) { fmt.Println("A request was rejected") })
-
Tollbooth does not require external storage since it uses an algorithm called Token Bucket (Go library: golang.org/x/time/rate).
Sometimes, other frameworks require a little bit of shim to use Tollbooth. These shims below are contributed by the community, so I make no promises on how well they work. The one I am familiar with are: Chi, Gin, and Negroni.
-
ErrStack: A small library to combine errors and also display filename and line number.
-
Stopwatch: A small library to measure latency of things. Useful if you want to report latency data to Graphite.
-
LaborUnion: A dynamic worker pool library.
-
Gomet: Simple HTTP client & server long poll library for Go. Useful for receiving live updates without needing Websocket.
Before sending a PR with code changes, please make sure altered code is covered with tests which are passing, and that golangci-lint shows no errors.
To check the linter output, install it and then run golangci-lint run in the root directory of the repository.
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