![Custom metrics
import p8s "github.com/prometheus/client_golang/prometheus"
var (
labelNames = []string{"affiliate", "status"}
responseCounter = p8s.NewCounterVec(p8s.CounterOpts{Name: "app_response_count"}, labelNames)
)
func init() {
p8s.MustRegister(responseCounter)
}
func countFailedResponse(affiliate string, reason string) {
responseCounter.WithLabelValues(affiliate, reason).Inc()
}
func countSuccessResponse(affiliate string) {
responseCounter.WithLabelValues(affiliate, "success").Inc()
}](https://image.slidesharecdn.com/rlreadyingyourgowebservice-190913084731/85/Meetup-talk-Readying-your-Go-Webservice-13-320.jpg)
![CORS middleware
import "github.com/rs/cors"
// WithCORS wraps the handler with CORS options.
func WithCORS(handlerFunc http.HandlerFunc) http.Handler {
corsOptions := cors.Options{
AllowedOrigins: []string{os.Getenv("CORS_ORIGINS")},
AllowedMethods: []string{"HEAD", "OPTIONS", "GET", "PUT", "POST"},
AllowedHeaders: []string{"Origin", "Accept", "Content-Type", "X-Requested-With", "X-CSRF-Token"},
ExposedHeaders: []string{
"Access-Control-Allow-Headers",
"Access-Control-Allow-Methods",
"Access-Control-Max-Age",
},
MaxAge: 0,
}
return cors.New(corsOptions).Handler(handlerFunc)
}](https://image.slidesharecdn.com/rlreadyingyourgowebservice-190913084731/85/Meetup-talk-Readying-your-Go-Webservice-29-320.jpg)
Meetup talk: Readying your Go Webservice
- 1. Readying your Go webservice Ralph Ligtenberg September 12, 2019 https://www.pexels.com/photo/web-close-up-photography-2632059/
- 2. Ralph Ligtenberg Tech Lead @ Travix C#, Go, Google Cloud Platform twitter.com/prutswonder medium.com/@prutswonder linkedin.com/in/ralphligtenberg
- 3. Done ❏ “Works on my machine” ❏ Merged to master ❏ Unit & Integration tests ❏ Works as expected Ready ❏ “Works anywhere” ❏ Deployed & tested ❏ Acceptance & load tests ❏ Performs as expected https://www.pexels.com/photo/photo-of-green-data-matrix-1089438/
- 4. ● CI/CD: build & deployment automation ● Observability: logging, monitoring & tracing ● Resilience: Circuit breaker & panic recovery ● Lifecycle management: warm-up & shutdown ● Security: authentication & authorization From “Done” to “Ready” https://www.pexels.com/photo/abstract-art-circle-clockwork-414579/
- 5. CI/CD: Kubernetes & Estafette https://www.pexels.com/photo/red-and-gray-industrial-machinery-2569842/
- 7. Estafette build stage # https://estafette.io/usage/manifest/#build-stages stages: test-lint-build: image: golang:1.13.0 env: CGO_ENABLED: 0 GOOS: linux GO111MODULE: "on" GOGC: off commands: - go get -u golang.org/x/lint/golint - CGO_ENABLED=1 go test -race -cover ./... - golint -set_exit_status ./... - go build -a -installsuffix cgo -o ./publish/${ESTAFETTE_LABEL_APP} .
- 8. Estafette docker image creation # https://estafette.io/usage/extensions/estafette-extensions/#extensions-docker bake: image: extensions/docker:stable action: build path: ./publish push: image: extensions/docker:stable action: push
- 9. Estafette deployment # https://estafette.io/usage/manifest/#releases releases: development: stages: deploy: image: extensions/gke:stable container: port: 8080 env: CORS_ORIGINS: "*" cpu: request: 10m limit: 100m memory: request: 25Mi limit: 100Mi # Continued on the right --> liveness: path: /live readiness: path: /ready sidecar: healthcheckpath: /live slack-notify: image: extensions/slack-build-status:stable workspace: travix channels: - '#{ESTAFETTE_LABEL_TEAM}-builds' when: status == 'failed'
- 10. Logging: ELK Stack & zerolog https://www.pexels.com/photo/bark-brown-cut-daylight-296333/
- 11. Logging import ( "os" "github.com/rs/zerolog" "github.com/rs/zerolog/log" ) // Logger is used to write log messages. type Logger struct { level zerolog.Level logger zerolog.Logger } // NewLogger sets and returns a new global-level logger. func NewLogger(appGroup, appName, logLevel string) Logger { zLogLevel := ToZeroLogLevel(logLevel) logger := log.Output(v3FormatWriter{Out: os.Stderr}).With(). Str("appgroup", appGroup).Str("appname", appName). Logger().Level(zLogLevel) log.Logger = logger return Logger{level: zLogLevel, logger: logger} }
- 12. Monitoring: Prometheus & Grafana https://www.pexels.com/photo/black-and-white-business-chart-computer-241544/
- 13. Custom metrics import p8s "github.com/prometheus/client_golang/prometheus" var ( labelNames = []string{"affiliate", "status"} responseCounter = p8s.NewCounterVec(p8s.CounterOpts{Name: "app_response_count"}, labelNames) ) func init() { p8s.MustRegister(responseCounter) } func countFailedResponse(affiliate string, reason string) { responseCounter.WithLabelValues(affiliate, reason).Inc() } func countSuccessResponse(affiliate string) { responseCounter.WithLabelValues(affiliate, "success").Inc() }
- 16. Tracing middleware // WithTracing creates a span for each request func WithTracing(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // retrieve span context from upstream caller if available tracingCtx, _ := opentracing.GlobalTracer().Extract(opentracing.HTTPHeaders, opentracing.HTTPHeadersCarrier(r.Header)) span := opentracing.StartSpan(fmt.Sprintf("%v %v", r.Method, r.URL.Path), ext.RPCServerOption(tracingCtx)) defer span.Finish() ext.HTTPMethod.Set(span, r.Method) ext.HTTPUrl.Set(span, r.URL.String()) tw := tracedResponseWriter{ResponseWriter: w} rc := r.WithContext(opentracing.ContextWithSpan(r.Context(), span)) next.ServeHTTP(&tw, rc) ext.HTTPStatusCode.Set(span, uint16(tw.Status())) }) }
- 17. Tracing: Jaeger
- 19. Circuit breaker // Try wraps a function with circuit breaking func (b *Breaker) Try(cmdKey string, tryFunc func() ( interface{}, error)) (interface{}, error) { type result struct { response interface{} err error } startTime := time.Now() cmd := b.getOrAddCommand(cmdKey) if !cmd.allowRequest() { cmd.registerShortCircuited() return nil, ErrRequestShortCircuited } // Continued on the right --> ch := make(chan result, 1) go func(ch chan result) { defer close(ch) response, err := tryFunc() ch <- result{response: response, err: err} }(ch) timer := time.NewTimer(cmd.timeout) defer timer.Stop() select { case res := <-ch: if res.err != nil { cmd.registerFailure(time.Since(startTime)) return nil, res.err } cmd.registerSuccess(time.Since(startTime)) return res.response, nil case <-timer.C: cmd.registerTimeout(time.Since(startTime)) return nil, &ErrRequestTimeout{commandKey: cmdKey, timeout: cmd.timeout} } }
- 20. Panic recovery middleware // WithPanicRecoveryFunc recovers any panics that occur in the next http handler. func WithPanicRecoveryFunc(logger logging.Logger, next http.HandlerFunc) http.HandlerFunc { return func(w http.ResponseWriter, r *http.Request) { defer func() { if rec := recover(); rec != nil { logger.Error("PanicRecovered"). Bytes("stacktrace", debug.Stack()). LogErr(fmt.Errorf("%s", rec)) w.WriteHeader(http.StatusInternalServerError) } }() next(w, r) } }
- 22. Server & start-up type shutdownFunc func() error type server struct { ctx context.Context version versionInfo shutdown shutdownFunc } func (s *server) Serve() { // (...) mux := http.NewServeMux() svr := http.Server{ ReadTimeout: time.Second * 3, ReadHeaderTimeout: time.Second * 2, WriteTimeout: time.Second * 10, Addr: ":8080", Handler: mux, } // Continued on the right --> mux.HandleFunc("/ready", s.ready) mux.HandleFunc("/live", s.live) // Put your own endpoints here err = s.setControllers(mux) if err != nil { log.Error("ServerControllerError").LogErr(err) return } _ = svr.ListenAndServe() // Blocks until server stops } func (s *server) live(w http.ResponseWriter, r *http.Request) { _, _ = io.WriteString(w, "Alive!") } func (s *server) ready(w http.ResponseWriter, r *http.Request) { //TODO: Determine readiness _, _ = io.WriteString(w, "Ready!") }
- 24. Server with graceful shutdown func (s *server) Serve() { // (...) s.shutdown = func() error { cancelCtx, cancel := context.WithTimeout(s.ctx, time.Second * 10) defer cancel() err := svr.Shutdown(cancelCtx) return err } signalCh := make(chan os.Signal, 1) go s.listenToShutdownSignals(signalCh) _ = svr.ListenAndServe() // Blocks until server stops } func (s *server) listenToShutdownSignals( signalCh chan os.Signal) { signal.Notify(signalCh, syscall.SIGINT, // kill -SIGINT XXXX or Ctrl+c syscall.SIGTERM, // kill -SIGTERM XXXX syscall.SIGQUIT) // kill -SIGQUIT XXXX for { sig := <-signalCh switch sig { case syscall.SIGINT: fallthrough case syscall.SIGTERM: fallthrough case syscall.SIGQUIT: s.shutdown() return } } }
- 26. Estafette & cloud credentials releases: development: stages: deploy: image: extensions/gke:stable visibility: public-whitelist container: # (...) sidecar: healthcheckpath: /live useGoogleCloudCredentials: true
- 27. Estafette secrets production: # https://estafette.io/usage/manifest/#release-actions actions: - name: deploy-canary - name: deploy-stable - name: rollback-canary stages: deploy: image: extensions/gke:stable visibility: public container: port: 8080 env: # AES-256-encrypted value AUTH_BASIC_TOKEN: estafette.secret(6J1RtwwpvMIhMtbE.QuRJhnTgO8FcHP-cEtJy72pTzaTw2L5-1zeT0A==)
- 28. Authorization middleware import "net/http" // WithAuthBasic performs a basic authorization check func WithAuthBasic(token string, next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { switch r.Header.Get("Authorization") { case "Basic " + token: next.ServeHTTP(w, r) case "": w.Header().Add("WWW-Authenticate", "Basic") w.WriteHeader(http.StatusUnauthorized) default: w.WriteHeader(http.StatusForbidden) } }) }
- 29. CORS middleware import "github.com/rs/cors" // WithCORS wraps the handler with CORS options. func WithCORS(handlerFunc http.HandlerFunc) http.Handler { corsOptions := cors.Options{ AllowedOrigins: []string{os.Getenv("CORS_ORIGINS")}, AllowedMethods: []string{"HEAD", "OPTIONS", "GET", "PUT", "POST"}, AllowedHeaders: []string{"Origin", "Accept", "Content-Type", "X-Requested-With", "X-CSRF-Token"}, ExposedHeaders: []string{ "Access-Control-Allow-Headers", "Access-Control-Allow-Methods", "Access-Control-Max-Age", }, MaxAge: 0, } return cors.New(corsOptions).Handler(handlerFunc) }
- 30. ● Automate builds & deployments for your webservice ● Observe your webservice ● Make your webservice resilient ● Warm up your webservice ● Shut down your webservice gracefully ● Secure your webservice Getting “Ready” https://www.pexels.com/photo/abstract-art-circle-clockwork-414579/
- 31. Estafette: https://estafette.io/ Zerolog: https://github.com/rs/zerolog Prometheus: https://github.com/prometheus/client_golang Grafana: https://grafana.com/ Jaeger: https://www.jaegertracing.io/ CORS: https://github.com/rs/cors Circuit breaker: https://martinfowler.com/bliki/CircuitBreaker.html References https://www.pexels.com/photo/abstract-art-circle-clockwork-414579/
- 32. Thank you! Ralph Ligtenberg - @prutswonder stock images downloaded from Pexels.com https://www.pexels.com/photo/silhouette-of-airplanes-47044/