package middleware import ( "context" "github.com/containous/alice" "github.com/traefik/traefik/v2/pkg/log" "github.com/traefik/traefik/v2/pkg/metrics" "github.com/traefik/traefik/v2/pkg/middlewares/accesslog" "github.com/traefik/traefik/v2/pkg/middlewares/capture" metricsmiddleware "github.com/traefik/traefik/v2/pkg/middlewares/metrics" mTracing "github.com/traefik/traefik/v2/pkg/middlewares/tracing" "github.com/traefik/traefik/v2/pkg/tracing" ) // ChainBuilder Creates a middleware chain by entry point. It is used for middlewares that are created almost systematically and that need to be created before all others. type ChainBuilder struct { metricsRegistry metrics.Registry accessLoggerMiddleware *accesslog.Handler tracer *tracing.Tracing } // NewChainBuilder Creates a new ChainBuilder. func NewChainBuilder(metricsRegistry metrics.Registry, accessLoggerMiddleware *accesslog.Handler, tracer *tracing.Tracing) *ChainBuilder { return &ChainBuilder{ metricsRegistry: metricsRegistry, accessLoggerMiddleware: accessLoggerMiddleware, tracer: tracer, } } // Build a middleware chain by entry point. func (c *ChainBuilder) Build(ctx context.Context, entryPointName string) alice.Chain { chain := alice.New() if c.accessLoggerMiddleware != nil || c.metricsRegistry != nil && (c.metricsRegistry.IsEpEnabled() || c.metricsRegistry.IsRouterEnabled() || c.metricsRegistry.IsSvcEnabled()) { chain = chain.Append(capture.Wrap) } if c.accessLoggerMiddleware != nil { chain = chain.Append(accesslog.WrapHandler(c.accessLoggerMiddleware)) } if c.tracer != nil { chain = chain.Append(mTracing.WrapEntryPointHandler(ctx, c.tracer, entryPointName)) } if c.metricsRegistry != nil && c.metricsRegistry.IsEpEnabled() { chain = chain.Append(metricsmiddleware.WrapEntryPointHandler(ctx, c.metricsRegistry, entryPointName)) } return chain } // Close accessLogger and tracer. func (c *ChainBuilder) Close() { if c.accessLoggerMiddleware != nil { if err := c.accessLoggerMiddleware.Close(); err != nil { log.WithoutContext().Errorf("Could not close the access log file: %s", err) } } if c.tracer != nil { c.tracer.Close() } }