go 1.8 net/http timeouts

GO1.8 NET/HTTP TIMEOUTS 2017-03-25 Tetsuya Morimoto

ABOUT ME Tetsuya Morimoto twitter: @t2y I like Python, Java and Go! Yahoo Japan Corporation Data & Science Solutions Group Apprentice Infrastructure engineer Mission: OPS → SRE

• https://twitter.com/t2y

RECENT WORK Qiita [຋༁]αΠτ৴པੑΤϯδχΞϦϯά(SRE)ͱ͸Կ͔ʁ 1/27 Go 1.8 ͷ Graceful Shutdown ͷৼΔ෣͍Λௐ΂ͯΈͨ 3/18 ल࿨γεςϜ 3/21 ϑϦʔϥΠϒϥϦͰֶͿ‫ػ‬ցֶशೖ໳ ෇࿥ࢿྉ ‫ߏڥ؀‬ங΍Python ೖ໳Λࣥච

• http://qiita.com/t2y/items/99e40560a67b76ea1ff5
• http://qiita.com/t2y/items/acd86fe24a25e996dbda
• https://www.amazon.co.jp/dp/4798049611

GO 1.8 FEATURE

MINOR CHANGES Go 1.8 net/http changes from release note “ The Server adds configuration options ReadHeaderTimeout and IdleTimeout and documents WriteTimeout. ”

• https://golang.org/doc/go1.8#net_http
• https://golang.org/pkg/net/http/#Server

NOTABLE ARTICLES https://blog.cloudflare.com/ The complete guide to Go net/http timeouts So you want to expose Go on the Internet Written by @FiloSottile (Filippo Valsorda) “ Back when crypto/tls was slow and net/http young, the general wisdom was to always put Go servers behind a reverse proxy like NGINX. That's not necessary anymore! ”

• https://blog.cloudflare.com/
• https://blog.cloudflare.com/the-complete-guide-to-golang-net-http-timeouts/
• https://blog.cloudflare.com/exposing-go-on-the-internet/
• https://twitter.com/FiloSottile

STUDY TIMEOUTS

SOCKET TIMEOUTS Transport Layer net.Conn interface SetDeadline (SetReadDeadline/SetWriteDeadline) I/O operation with timeout Let’s Socket Programming! ɾsocket Socket is an API working on transport layer ɾbind GoͰͨͨ͘TCPιέοτʢલฤʣ ɾlisten ɾaccept GoͰͨͨ͘TCPιέοτʢ‫ޙ‬ฤʣ Conn

• https://github.com/golang/go/blob/cd6b6202/src/net/net.go#L138
• http://ascii.jp/elem/000/001/276/1276572/
• http://ascii.jp/elem/000/001/403/1403717/

HTTP SERVER TIMEOUTS Application Layer Go1.7 Go1.8 ReadHeaderTimeout new! These images are quoted from Filippo’s article on https://blog.cloudflare.com

• https://blog.cloudflare.com

HTTP SERVER TIMEOUTS Application Layer net/http: no way of manipulating timeouts in Handler #16100 issued at 2016-06-18 (Go 1.6.x) Go 1.8 introduces ReadHeaderTimeout Reset read deadline after reading the request header “ Go 1.8 introduces ReadHeaderTimeout, which only covers up to the request headers. However, there's still no clear way to do reads with timeouts from a Handler. ”

• https://github.com/golang/go/issues/16100
• https://github.com/golang/go/blob/cd6b6202/src/net/http/server.go#L2326

HTTP CLIENT TIMEOUTS Application Layer “ Client-side timeouts can be simpler or much more complex, … ” This image is quoted from Filippo’s article on https://blog.cloudflare.com

• https://blog.cloudflare.com

CONTEXT PACKAGE
context is standard way

ctx, cancel := context.WithCancel(context.TODO())

the advantage

timer := time.AfterFunc(5*time.Second, func() {

a request will cancel if
parent context would
cancel

cancel()
})
req, err := http.NewRequest("GET", “http://
example.com”, nil)
if err != nil {
log.Fatal(err)
}
req = req.WithContext(ctx)

• http://example.com

SUMMARY Timeouts is important for effective/stable Web service. including against malicious attack (DoS/DDoS) Go 1.8 http.Server is enough stable!