639 lines
31 KiB
Markdown
639 lines
31 KiB
Markdown
# fasthttp [](https://pkg.go.dev/github.com/valyala/fasthttp) [](https://goreportcard.com/report/github.com/valyala/fasthttp)
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Fast HTTP implementation for Go.
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# fasthttp might not be for you!
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fasthttp was designed for some high performance edge cases. **Unless** your server/client needs to handle **thousands of small to medium requests per second** and needs a consistent low millisecond response time fasthttp might not be for you. **For most cases `net/http` is much better** as it's easier to use and can handle more cases. For most cases you won't even notice the performance difference.
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## General info and links
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Currently fasthttp is successfully used by [VertaMedia](https://vertamedia.com/)
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in a production serving up to 200K rps from more than 1.5M concurrent keep-alive
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connections per physical server.
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[TechEmpower Benchmark round 19 results](https://www.techempower.com/benchmarks/#section=data-r19&hw=ph&test=plaintext)
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[Server Benchmarks](#http-server-performance-comparison-with-nethttp)
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[Client Benchmarks](#http-client-comparison-with-nethttp)
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[Install](#install)
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[Documentation](https://pkg.go.dev/github.com/valyala/fasthttp)
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[Examples from docs](https://pkg.go.dev/github.com/valyala/fasthttp#pkg-examples)
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[Code examples](examples)
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[Awesome fasthttp tools](https://github.com/fasthttp)
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[Switching from net/http to fasthttp](#switching-from-nethttp-to-fasthttp)
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[Fasthttp best practices](#fasthttp-best-practices)
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[Tricks with byte buffers](#tricks-with-byte-buffers)
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[Related projects](#related-projects)
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[FAQ](#faq)
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## HTTP server performance comparison with [net/http](https://pkg.go.dev/net/http)
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In short, fasthttp server is up to 10 times faster than net/http.
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Below are benchmark results.
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*GOMAXPROCS=1*
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net/http server:
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```
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$ GOMAXPROCS=1 go test -bench=NetHTTPServerGet -benchmem -benchtime=10s
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BenchmarkNetHTTPServerGet1ReqPerConn 1000000 12052 ns/op 2297 B/op 29 allocs/op
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BenchmarkNetHTTPServerGet2ReqPerConn 1000000 12278 ns/op 2327 B/op 24 allocs/op
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BenchmarkNetHTTPServerGet10ReqPerConn 2000000 8903 ns/op 2112 B/op 19 allocs/op
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BenchmarkNetHTTPServerGet10KReqPerConn 2000000 8451 ns/op 2058 B/op 18 allocs/op
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BenchmarkNetHTTPServerGet1ReqPerConn10KClients 500000 26733 ns/op 3229 B/op 29 allocs/op
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BenchmarkNetHTTPServerGet2ReqPerConn10KClients 1000000 23351 ns/op 3211 B/op 24 allocs/op
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BenchmarkNetHTTPServerGet10ReqPerConn10KClients 1000000 13390 ns/op 2483 B/op 19 allocs/op
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BenchmarkNetHTTPServerGet100ReqPerConn10KClients 1000000 13484 ns/op 2171 B/op 18 allocs/op
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```
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fasthttp server:
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```
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$ GOMAXPROCS=1 go test -bench=kServerGet -benchmem -benchtime=10s
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BenchmarkServerGet1ReqPerConn 10000000 1559 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet2ReqPerConn 10000000 1248 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet10ReqPerConn 20000000 797 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet10KReqPerConn 20000000 716 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet1ReqPerConn10KClients 10000000 1974 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet2ReqPerConn10KClients 10000000 1352 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet10ReqPerConn10KClients 20000000 789 ns/op 2 B/op 0 allocs/op
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BenchmarkServerGet100ReqPerConn10KClients 20000000 604 ns/op 0 B/op 0 allocs/op
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```
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*GOMAXPROCS=4*
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net/http server:
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```
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$ GOMAXPROCS=4 go test -bench=NetHTTPServerGet -benchmem -benchtime=10s
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BenchmarkNetHTTPServerGet1ReqPerConn-4 3000000 4529 ns/op 2389 B/op 29 allocs/op
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BenchmarkNetHTTPServerGet2ReqPerConn-4 5000000 3896 ns/op 2418 B/op 24 allocs/op
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BenchmarkNetHTTPServerGet10ReqPerConn-4 5000000 3145 ns/op 2160 B/op 19 allocs/op
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BenchmarkNetHTTPServerGet10KReqPerConn-4 5000000 3054 ns/op 2065 B/op 18 allocs/op
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BenchmarkNetHTTPServerGet1ReqPerConn10KClients-4 1000000 10321 ns/op 3710 B/op 30 allocs/op
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BenchmarkNetHTTPServerGet2ReqPerConn10KClients-4 2000000 7556 ns/op 3296 B/op 24 allocs/op
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BenchmarkNetHTTPServerGet10ReqPerConn10KClients-4 5000000 3905 ns/op 2349 B/op 19 allocs/op
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BenchmarkNetHTTPServerGet100ReqPerConn10KClients-4 5000000 3435 ns/op 2130 B/op 18 allocs/op
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```
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fasthttp server:
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```
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$ GOMAXPROCS=4 go test -bench=kServerGet -benchmem -benchtime=10s
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BenchmarkServerGet1ReqPerConn-4 10000000 1141 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet2ReqPerConn-4 20000000 707 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet10ReqPerConn-4 30000000 341 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet10KReqPerConn-4 50000000 310 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet1ReqPerConn10KClients-4 10000000 1119 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet2ReqPerConn10KClients-4 20000000 644 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet10ReqPerConn10KClients-4 30000000 346 ns/op 0 B/op 0 allocs/op
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BenchmarkServerGet100ReqPerConn10KClients-4 50000000 282 ns/op 0 B/op 0 allocs/op
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```
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## HTTP client comparison with net/http
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In short, fasthttp client is up to 10 times faster than net/http.
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Below are benchmark results.
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*GOMAXPROCS=1*
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net/http client:
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```
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$ GOMAXPROCS=1 go test -bench='HTTPClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
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BenchmarkNetHTTPClientDoFastServer 1000000 12567 ns/op 2616 B/op 35 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd1TCP 200000 67030 ns/op 5028 B/op 56 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd10TCP 300000 51098 ns/op 5031 B/op 56 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd100TCP 300000 45096 ns/op 5026 B/op 55 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd1Inmemory 500000 24779 ns/op 5035 B/op 57 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd10Inmemory 1000000 26425 ns/op 5035 B/op 57 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd100Inmemory 500000 28515 ns/op 5045 B/op 57 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd1000Inmemory 500000 39511 ns/op 5096 B/op 56 allocs/op
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```
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fasthttp client:
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```
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$ GOMAXPROCS=1 go test -bench='kClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
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BenchmarkClientDoFastServer 20000000 865 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd1TCP 1000000 18711 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd10TCP 1000000 14664 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd100TCP 1000000 14043 ns/op 1 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd1Inmemory 5000000 3965 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd10Inmemory 3000000 4060 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd100Inmemory 5000000 3396 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd1000Inmemory 5000000 3306 ns/op 2 B/op 0 allocs/op
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```
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*GOMAXPROCS=4*
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net/http client:
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```
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$ GOMAXPROCS=4 go test -bench='HTTPClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
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BenchmarkNetHTTPClientDoFastServer-4 2000000 8774 ns/op 2619 B/op 35 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd1TCP-4 500000 22951 ns/op 5047 B/op 56 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd10TCP-4 1000000 19182 ns/op 5037 B/op 55 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd100TCP-4 1000000 16535 ns/op 5031 B/op 55 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd1Inmemory-4 1000000 14495 ns/op 5038 B/op 56 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd10Inmemory-4 1000000 10237 ns/op 5034 B/op 56 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd100Inmemory-4 1000000 10125 ns/op 5045 B/op 56 allocs/op
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BenchmarkNetHTTPClientGetEndToEnd1000Inmemory-4 1000000 11132 ns/op 5136 B/op 56 allocs/op
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```
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fasthttp client:
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```
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$ GOMAXPROCS=4 go test -bench='kClient(Do|GetEndToEnd)' -benchmem -benchtime=10s
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BenchmarkClientDoFastServer-4 50000000 397 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd1TCP-4 2000000 7388 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd10TCP-4 2000000 6689 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd100TCP-4 3000000 4927 ns/op 1 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd1Inmemory-4 10000000 1604 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd10Inmemory-4 10000000 1458 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd100Inmemory-4 10000000 1329 ns/op 0 B/op 0 allocs/op
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BenchmarkClientGetEndToEnd1000Inmemory-4 10000000 1316 ns/op 5 B/op 0 allocs/op
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```
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## Install
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```
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go get -u github.com/valyala/fasthttp
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```
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## Switching from net/http to fasthttp
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Unfortunately, fasthttp doesn't provide API identical to net/http.
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See the [FAQ](#faq) for details.
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There is [net/http -> fasthttp handler converter](https://pkg.go.dev/github.com/valyala/fasthttp/fasthttpadaptor),
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but it is better to write fasthttp request handlers by hand in order to use
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all of the fasthttp advantages (especially high performance :) ).
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Important points:
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* Fasthttp works with [RequestHandler functions](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHandler)
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instead of objects implementing [Handler interface](https://pkg.go.dev/net/http#Handler).
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Fortunately, it is easy to pass bound struct methods to fasthttp:
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```go
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type MyHandler struct {
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foobar string
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}
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// request handler in net/http style, i.e. method bound to MyHandler struct.
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func (h *MyHandler) HandleFastHTTP(ctx *fasthttp.RequestCtx) {
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// notice that we may access MyHandler properties here - see h.foobar.
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fmt.Fprintf(ctx, "Hello, world! Requested path is %q. Foobar is %q",
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ctx.Path(), h.foobar)
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}
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// request handler in fasthttp style, i.e. just plain function.
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func fastHTTPHandler(ctx *fasthttp.RequestCtx) {
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fmt.Fprintf(ctx, "Hi there! RequestURI is %q", ctx.RequestURI())
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}
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// pass bound struct method to fasthttp
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myHandler := &MyHandler{
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foobar: "foobar",
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}
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fasthttp.ListenAndServe(":8080", myHandler.HandleFastHTTP)
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// pass plain function to fasthttp
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fasthttp.ListenAndServe(":8081", fastHTTPHandler)
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```
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* The [RequestHandler](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHandler)
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accepts only one argument - [RequestCtx](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx).
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It contains all the functionality required for http request processing
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and response writing. Below is an example of a simple request handler conversion
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from net/http to fasthttp.
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```go
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// net/http request handler
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requestHandler := func(w http.ResponseWriter, r *http.Request) {
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switch r.URL.Path {
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case "/foo":
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fooHandler(w, r)
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case "/bar":
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barHandler(w, r)
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default:
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http.Error(w, "Unsupported path", http.StatusNotFound)
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}
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}
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```
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```go
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// the corresponding fasthttp request handler
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requestHandler := func(ctx *fasthttp.RequestCtx) {
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switch string(ctx.Path()) {
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case "/foo":
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fooHandler(ctx)
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case "/bar":
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barHandler(ctx)
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default:
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ctx.Error("Unsupported path", fasthttp.StatusNotFound)
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}
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}
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```
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* Fasthttp allows setting response headers and writing response body
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in an arbitrary order. There is no 'headers first, then body' restriction
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like in net/http. The following code is valid for fasthttp:
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```go
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requestHandler := func(ctx *fasthttp.RequestCtx) {
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// set some headers and status code first
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ctx.SetContentType("foo/bar")
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ctx.SetStatusCode(fasthttp.StatusOK)
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// then write the first part of body
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fmt.Fprintf(ctx, "this is the first part of body\n")
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// then set more headers
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ctx.Response.Header.Set("Foo-Bar", "baz")
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// then write more body
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fmt.Fprintf(ctx, "this is the second part of body\n")
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// then override already written body
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ctx.SetBody([]byte("this is completely new body contents"))
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// then update status code
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ctx.SetStatusCode(fasthttp.StatusNotFound)
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// basically, anything may be updated many times before
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// returning from RequestHandler.
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//
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// Unlike net/http fasthttp doesn't put response to the wire until
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// returning from RequestHandler.
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}
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```
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* Fasthttp doesn't provide [ServeMux](https://pkg.go.dev/net/http#ServeMux),
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but there are more powerful third-party routers and web frameworks
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with fasthttp support:
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* [fasthttp-routing](https://github.com/qiangxue/fasthttp-routing)
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* [router](https://github.com/fasthttp/router)
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* [lu](https://github.com/vincentLiuxiang/lu)
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* [atreugo](https://github.com/savsgio/atreugo)
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* [Fiber](https://github.com/gofiber/fiber)
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* [Gearbox](https://github.com/gogearbox/gearbox)
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Net/http code with simple ServeMux is trivially converted to fasthttp code:
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```go
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// net/http code
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m := &http.ServeMux{}
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m.HandleFunc("/foo", fooHandlerFunc)
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m.HandleFunc("/bar", barHandlerFunc)
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m.Handle("/baz", bazHandler)
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http.ListenAndServe(":80", m)
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```
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```go
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// the corresponding fasthttp code
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m := func(ctx *fasthttp.RequestCtx) {
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switch string(ctx.Path()) {
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case "/foo":
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fooHandlerFunc(ctx)
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case "/bar":
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barHandlerFunc(ctx)
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case "/baz":
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bazHandler.HandlerFunc(ctx)
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default:
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ctx.Error("not found", fasthttp.StatusNotFound)
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}
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}
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fasthttp.ListenAndServe(":80", m)
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```
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* Because creating a new channel for every request is just too expensive, so the channel returned by RequestCtx.Done() is only closed when the server is shutting down.
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```go
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func main() {
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fasthttp.ListenAndServe(":8080", fasthttp.TimeoutHandler(func(ctx *fasthttp.RequestCtx) {
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select {
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case <-ctx.Done():
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// ctx.Done() is only closed when the server is shutting down.
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log.Println("context cancelled")
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return
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case <-time.After(10 * time.Second):
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log.Println("process finished ok")
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}
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}, time.Second*2, "timeout"))
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}
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```
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* net/http -> fasthttp conversion table:
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* All the pseudocode below assumes w, r and ctx have these types:
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```go
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var (
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w http.ResponseWriter
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r *http.Request
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ctx *fasthttp.RequestCtx
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)
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```
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* r.Body -> [ctx.PostBody()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.PostBody)
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* r.URL.Path -> [ctx.Path()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Path)
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* r.URL -> [ctx.URI()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.URI)
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* r.Method -> [ctx.Method()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Method)
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* r.Header -> [ctx.Request.Header](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHeader)
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* r.Header.Get() -> [ctx.Request.Header.Peek()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHeader.Peek)
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* r.Host -> [ctx.Host()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Host)
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* r.Form -> [ctx.QueryArgs()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.QueryArgs) +
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[ctx.PostArgs()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.PostArgs)
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* r.PostForm -> [ctx.PostArgs()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.PostArgs)
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* r.FormValue() -> [ctx.FormValue()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.FormValue)
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* r.FormFile() -> [ctx.FormFile()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.FormFile)
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* r.MultipartForm -> [ctx.MultipartForm()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.MultipartForm)
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* r.RemoteAddr -> [ctx.RemoteAddr()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.RemoteAddr)
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* r.RequestURI -> [ctx.RequestURI()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.RequestURI)
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* r.TLS -> [ctx.IsTLS()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.IsTLS)
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* r.Cookie() -> [ctx.Request.Header.Cookie()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHeader.Cookie)
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* r.Referer() -> [ctx.Referer()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Referer)
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* r.UserAgent() -> [ctx.UserAgent()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.UserAgent)
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* w.Header() -> [ctx.Response.Header](https://pkg.go.dev/github.com/valyala/fasthttp#ResponseHeader)
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* w.Header().Set() -> [ctx.Response.Header.Set()](https://pkg.go.dev/github.com/valyala/fasthttp#ResponseHeader.Set)
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* w.Header().Set("Content-Type") -> [ctx.SetContentType()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.SetContentType)
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* w.Header().Set("Set-Cookie") -> [ctx.Response.Header.SetCookie()](https://pkg.go.dev/github.com/valyala/fasthttp#ResponseHeader.SetCookie)
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* w.Write() -> [ctx.Write()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Write),
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[ctx.SetBody()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.SetBody),
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[ctx.SetBodyStream()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.SetBodyStream),
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[ctx.SetBodyStreamWriter()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.SetBodyStreamWriter)
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* w.WriteHeader() -> [ctx.SetStatusCode()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.SetStatusCode)
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* w.(http.Hijacker).Hijack() -> [ctx.Hijack()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Hijack)
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* http.Error() -> [ctx.Error()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Error)
|
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* http.FileServer() -> [fasthttp.FSHandler()](https://pkg.go.dev/github.com/valyala/fasthttp#FSHandler),
|
||
[fasthttp.FS](https://pkg.go.dev/github.com/valyala/fasthttp#FS)
|
||
* http.ServeFile() -> [fasthttp.ServeFile()](https://pkg.go.dev/github.com/valyala/fasthttp#ServeFile)
|
||
* http.Redirect() -> [ctx.Redirect()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Redirect)
|
||
* http.NotFound() -> [ctx.NotFound()](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.NotFound)
|
||
* http.StripPrefix() -> [fasthttp.PathRewriteFunc](https://pkg.go.dev/github.com/valyala/fasthttp#PathRewriteFunc)
|
||
|
||
* *VERY IMPORTANT!* Fasthttp disallows holding references
|
||
to [RequestCtx](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx) or to its'
|
||
members after returning from [RequestHandler](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHandler).
|
||
Otherwise [data races](http://go.dev/blog/race-detector) are inevitable.
|
||
Carefully inspect all the net/http request handlers converted to fasthttp whether
|
||
they retain references to RequestCtx or to its' members after returning.
|
||
RequestCtx provides the following _band aids_ for this case:
|
||
|
||
* Wrap RequestHandler into [TimeoutHandler](https://pkg.go.dev/github.com/valyala/fasthttp#TimeoutHandler).
|
||
* Call [TimeoutError](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.TimeoutError)
|
||
before returning from RequestHandler if there are references to RequestCtx or to its' members.
|
||
See [the example](https://pkg.go.dev/github.com/valyala/fasthttp#example-RequestCtx-TimeoutError)
|
||
for more details.
|
||
|
||
Use this brilliant tool - [race detector](http://go.dev/blog/race-detector) -
|
||
for detecting and eliminating data races in your program. If you detected
|
||
data race related to fasthttp in your program, then there is high probability
|
||
you forgot calling [TimeoutError](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.TimeoutError)
|
||
before returning from [RequestHandler](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHandler).
|
||
|
||
* Blind switching from net/http to fasthttp won't give you performance boost.
|
||
While fasthttp is optimized for speed, its' performance may be easily saturated
|
||
by slow [RequestHandler](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHandler).
|
||
So [profile](http://go.dev/blog/pprof) and optimize your
|
||
code after switching to fasthttp. For instance, use [quicktemplate](https://github.com/valyala/quicktemplate)
|
||
instead of [html/template](https://pkg.go.dev/html/template).
|
||
|
||
* See also [fasthttputil](https://pkg.go.dev/github.com/valyala/fasthttp/fasthttputil),
|
||
[fasthttpadaptor](https://pkg.go.dev/github.com/valyala/fasthttp/fasthttpadaptor) and
|
||
[expvarhandler](https://pkg.go.dev/github.com/valyala/fasthttp/expvarhandler).
|
||
|
||
|
||
## Performance optimization tips for multi-core systems
|
||
|
||
* Use [reuseport](https://pkg.go.dev/github.com/valyala/fasthttp/reuseport) listener.
|
||
* Run a separate server instance per CPU core with GOMAXPROCS=1.
|
||
* Pin each server instance to a separate CPU core using [taskset](http://linux.die.net/man/1/taskset).
|
||
* Ensure the interrupts of multiqueue network card are evenly distributed between CPU cores.
|
||
See [this article](https://blog.cloudflare.com/how-to-achieve-low-latency/) for details.
|
||
* Use the latest version of Go as each version contains performance improvements.
|
||
|
||
|
||
## Fasthttp best practices
|
||
|
||
* Do not allocate objects and `[]byte` buffers - just reuse them as much
|
||
as possible. Fasthttp API design encourages this.
|
||
* [sync.Pool](https://pkg.go.dev/sync#Pool) is your best friend.
|
||
* [Profile your program](http://go.dev/blog/pprof)
|
||
in production.
|
||
`go tool pprof --alloc_objects your-program mem.pprof` usually gives better
|
||
insights for optimization opportunities than `go tool pprof your-program cpu.pprof`.
|
||
* Write [tests and benchmarks](https://pkg.go.dev/testing) for hot paths.
|
||
* Avoid conversion between `[]byte` and `string`, since this may result in memory
|
||
allocation+copy. Fasthttp API provides functions for both `[]byte` and `string` -
|
||
use these functions instead of converting manually between `[]byte` and `string`.
|
||
There are some exceptions - see [this wiki page](https://github.com/golang/go/wiki/CompilerOptimizations#string-and-byte)
|
||
for more details.
|
||
* Verify your tests and production code under
|
||
[race detector](https://go.dev/doc/articles/race_detector.html) on a regular basis.
|
||
* Prefer [quicktemplate](https://github.com/valyala/quicktemplate) instead of
|
||
[html/template](https://pkg.go.dev/html/template) in your webserver.
|
||
|
||
|
||
## Tricks with `[]byte` buffers
|
||
|
||
The following tricks are used by fasthttp. Use them in your code too.
|
||
|
||
* Standard Go functions accept nil buffers
|
||
```go
|
||
var (
|
||
// both buffers are uninitialized
|
||
dst []byte
|
||
src []byte
|
||
)
|
||
dst = append(dst, src...) // is legal if dst is nil and/or src is nil
|
||
copy(dst, src) // is legal if dst is nil and/or src is nil
|
||
(string(src) == "") // is true if src is nil
|
||
(len(src) == 0) // is true if src is nil
|
||
src = src[:0] // works like a charm with nil src
|
||
|
||
// this for loop doesn't panic if src is nil
|
||
for i, ch := range src {
|
||
doSomething(i, ch)
|
||
}
|
||
```
|
||
|
||
So throw away nil checks for `[]byte` buffers from you code. For example,
|
||
```go
|
||
srcLen := 0
|
||
if src != nil {
|
||
srcLen = len(src)
|
||
}
|
||
```
|
||
|
||
becomes
|
||
|
||
```go
|
||
srcLen := len(src)
|
||
```
|
||
|
||
* String may be appended to `[]byte` buffer with `append`
|
||
```go
|
||
dst = append(dst, "foobar"...)
|
||
```
|
||
|
||
* `[]byte` buffer may be extended to its' capacity.
|
||
```go
|
||
buf := make([]byte, 100)
|
||
a := buf[:10] // len(a) == 10, cap(a) == 100.
|
||
b := a[:100] // is valid, since cap(a) == 100.
|
||
```
|
||
|
||
* All fasthttp functions accept nil `[]byte` buffer
|
||
```go
|
||
statusCode, body, err := fasthttp.Get(nil, "http://google.com/")
|
||
uintBuf := fasthttp.AppendUint(nil, 1234)
|
||
```
|
||
|
||
* String and `[]byte` buffers may converted without memory allocations
|
||
```go
|
||
func b2s(b []byte) string {
|
||
return *(*string)(unsafe.Pointer(&b))
|
||
}
|
||
|
||
func s2b(s string) (b []byte) {
|
||
bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
|
||
sh := (*reflect.StringHeader)(unsafe.Pointer(&s))
|
||
bh.Data = sh.Data
|
||
bh.Cap = sh.Len
|
||
bh.Len = sh.Len
|
||
return b
|
||
}
|
||
```
|
||
|
||
### Warning:
|
||
This is an **unsafe** way, the result string and `[]byte` buffer share the same bytes.
|
||
|
||
**Please make sure not to modify the bytes in the `[]byte` buffer if the string still survives!**
|
||
|
||
## Related projects
|
||
|
||
* [fasthttp](https://github.com/fasthttp) - various useful
|
||
helpers for projects based on fasthttp.
|
||
* [fasthttp-routing](https://github.com/qiangxue/fasthttp-routing) - fast and
|
||
powerful routing package for fasthttp servers.
|
||
* [http2](https://github.com/dgrr/http2) - HTTP/2 implementation for fasthttp.
|
||
* [router](https://github.com/fasthttp/router) - a high
|
||
performance fasthttp request router that scales well.
|
||
* [fastws](https://github.com/fasthttp/fastws) - Bloatless WebSocket package made for fasthttp
|
||
to handle Read/Write operations concurrently.
|
||
* [gramework](https://github.com/gramework/gramework) - a web framework made by one of fasthttp maintainers
|
||
* [lu](https://github.com/vincentLiuxiang/lu) - a high performance
|
||
go middleware web framework which is based on fasthttp.
|
||
* [websocket](https://github.com/fasthttp/websocket) - Gorilla-based
|
||
websocket implementation for fasthttp.
|
||
* [websocket](https://github.com/dgrr/websocket) - Event-based high-performance WebSocket library for zero-allocation
|
||
websocket servers and clients.
|
||
* [fasthttpsession](https://github.com/phachon/fasthttpsession) - a fast and powerful session package for fasthttp servers.
|
||
* [atreugo](https://github.com/savsgio/atreugo) - High performance and extensible micro web framework with zero memory allocations in hot paths.
|
||
* [kratgo](https://github.com/savsgio/kratgo) - Simple, lightweight and ultra-fast HTTP Cache to speed up your websites.
|
||
* [kit-plugins](https://github.com/wencan/kit-plugins/tree/master/transport/fasthttp) - go-kit transport implementation for fasthttp.
|
||
* [Fiber](https://github.com/gofiber/fiber) - An Expressjs inspired web framework running on Fasthttp
|
||
* [Gearbox](https://github.com/gogearbox/gearbox) - :gear: gearbox is a web framework written in Go with a focus on high performance and memory optimization
|
||
* [http2curl](https://github.com/li-jin-gou/http2curl) - A tool to convert fasthttp requests to curl command line
|
||
|
||
## FAQ
|
||
|
||
* *Why creating yet another http package instead of optimizing net/http?*
|
||
|
||
Because net/http API limits many optimization opportunities.
|
||
For example:
|
||
* net/http Request object lifetime isn't limited by request handler execution
|
||
time. So the server must create a new request object per each request instead
|
||
of reusing existing objects like fasthttp does.
|
||
* net/http headers are stored in a `map[string][]string`. So the server
|
||
must parse all the headers, convert them from `[]byte` to `string` and put
|
||
them into the map before calling user-provided request handler.
|
||
This all requires unnecessary memory allocations avoided by fasthttp.
|
||
* net/http client API requires creating a new response object per each request.
|
||
|
||
* *Why fasthttp API is incompatible with net/http?*
|
||
|
||
Because net/http API limits many optimization opportunities. See the answer
|
||
above for more details. Also certain net/http API parts are suboptimal
|
||
for use:
|
||
* Compare [net/http connection hijacking](https://pkg.go.dev/net/http#Hijacker)
|
||
to [fasthttp connection hijacking](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Hijack).
|
||
* Compare [net/http Request.Body reading](https://pkg.go.dev/net/http#Request)
|
||
to [fasthttp request body reading](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.PostBody).
|
||
|
||
* *Why fasthttp doesn't support HTTP/2.0 and WebSockets?*
|
||
|
||
[HTTP/2.0 support](https://github.com/fasthttp/http2) is in progress. [WebSockets](https://github.com/fasthttp/websockets) has been done already.
|
||
Third parties also may use [RequestCtx.Hijack](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.Hijack)
|
||
for implementing these goodies.
|
||
|
||
* *Are there known net/http advantages comparing to fasthttp?*
|
||
|
||
Yes:
|
||
* net/http supports [HTTP/2.0 starting from go1.6](https://pkg.go.dev/golang.org/x/net/http2).
|
||
* net/http API is stable, while fasthttp API constantly evolves.
|
||
* net/http handles more HTTP corner cases.
|
||
* net/http can stream both request and response bodies
|
||
* net/http can handle bigger bodies as it doesn't read the whole body into memory
|
||
* net/http should contain less bugs, since it is used and tested by much
|
||
wider audience.
|
||
|
||
* *Why fasthttp API prefers returning `[]byte` instead of `string`?*
|
||
|
||
Because `[]byte` to `string` conversion isn't free - it requires memory
|
||
allocation and copy. Feel free wrapping returned `[]byte` result into
|
||
`string()` if you prefer working with strings instead of byte slices.
|
||
But be aware that this has non-zero overhead.
|
||
|
||
* *Which GO versions are supported by fasthttp?*
|
||
|
||
Go 1.15.x. Older versions won't be supported.
|
||
|
||
* *Please provide real benchmark data and server information*
|
||
|
||
See [this issue](https://github.com/valyala/fasthttp/issues/4).
|
||
|
||
* *Are there plans to add request routing to fasthttp?*
|
||
|
||
There are no plans to add request routing into fasthttp.
|
||
Use third-party routers and web frameworks with fasthttp support:
|
||
|
||
* [fasthttp-routing](https://github.com/qiangxue/fasthttp-routing)
|
||
* [router](https://github.com/fasthttp/router)
|
||
* [gramework](https://github.com/gramework/gramework)
|
||
* [lu](https://github.com/vincentLiuxiang/lu)
|
||
* [atreugo](https://github.com/savsgio/atreugo)
|
||
* [Fiber](https://github.com/gofiber/fiber)
|
||
* [Gearbox](https://github.com/gogearbox/gearbox)
|
||
|
||
See also [this issue](https://github.com/valyala/fasthttp/issues/9) for more info.
|
||
|
||
* *I detected data race in fasthttp!*
|
||
|
||
Cool! [File a bug](https://github.com/valyala/fasthttp/issues/new). But before
|
||
doing this check the following in your code:
|
||
|
||
* Make sure there are no references to [RequestCtx](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx)
|
||
or to its' members after returning from [RequestHandler](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHandler).
|
||
* Make sure you call [TimeoutError](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx.TimeoutError)
|
||
before returning from [RequestHandler](https://pkg.go.dev/github.com/valyala/fasthttp#RequestHandler)
|
||
if there are references to [RequestCtx](https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx)
|
||
or to its' members, which may be accessed by other goroutines.
|
||
|
||
* *I didn't find an answer for my question here*
|
||
|
||
Try exploring [these questions](https://github.com/valyala/fasthttp/issues?q=label%3Aquestion).
|