package circuitbreaker import ( "context" "net/http" "time" "github.com/opentracing/opentracing-go/ext" "github.com/rs/zerolog" "github.com/rs/zerolog/log" "github.com/traefik/traefik/v2/pkg/config/dynamic" "github.com/traefik/traefik/v2/pkg/logs" "github.com/traefik/traefik/v2/pkg/middlewares" "github.com/traefik/traefik/v2/pkg/tracing" "github.com/vulcand/oxy/v2/cbreaker" ) const typeName = "CircuitBreaker" type circuitBreaker struct { circuitBreaker *cbreaker.CircuitBreaker name string } // New creates a new circuit breaker middleware. func New(ctx context.Context, next http.Handler, confCircuitBreaker dynamic.CircuitBreaker, name string) (http.Handler, error) { expression := confCircuitBreaker.Expression logger := middlewares.GetLogger(ctx, name, typeName) logger.Debug().Msg("Creating middleware") logger.Debug().Msgf("Setting up with expression: %s", expression) cbOpts := []cbreaker.Option{ cbreaker.Fallback(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) { tracing.SetErrorWithEvent(req, "blocked by circuit-breaker (%q)", expression) rw.WriteHeader(http.StatusServiceUnavailable) if _, err := rw.Write([]byte(http.StatusText(http.StatusServiceUnavailable))); err != nil { log.Ctx(req.Context()).Error().Err(err).Send() } })), cbreaker.Logger(logs.NewOxyWrapper(*logger)), cbreaker.Verbose(logger.GetLevel() == zerolog.TraceLevel), } if confCircuitBreaker.CheckPeriod > 0 { cbOpts = append(cbOpts, cbreaker.CheckPeriod(time.Duration(confCircuitBreaker.CheckPeriod))) } if confCircuitBreaker.FallbackDuration > 0 { cbOpts = append(cbOpts, cbreaker.FallbackDuration(time.Duration(confCircuitBreaker.FallbackDuration))) } if confCircuitBreaker.RecoveryDuration > 0 { cbOpts = append(cbOpts, cbreaker.RecoveryDuration(time.Duration(confCircuitBreaker.RecoveryDuration))) } oxyCircuitBreaker, err := cbreaker.New(next, expression, cbOpts...) if err != nil { return nil, err } return &circuitBreaker{ circuitBreaker: oxyCircuitBreaker, name: name, }, nil } func (c *circuitBreaker) GetTracingInformation() (string, ext.SpanKindEnum) { return c.name, tracing.SpanKindNoneEnum } func (c *circuitBreaker) ServeHTTP(rw http.ResponseWriter, req *http.Request) { c.circuitBreaker.ServeHTTP(rw, req) }