392 lines
11 KiB
Go
392 lines
11 KiB
Go
package middleware
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import (
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"context"
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"errors"
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"fmt"
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"net/http"
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"reflect"
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"strings"
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"github.com/containous/alice"
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"github.com/traefik/traefik/v2/pkg/config/runtime"
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"github.com/traefik/traefik/v2/pkg/log"
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"github.com/traefik/traefik/v2/pkg/middlewares/addprefix"
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"github.com/traefik/traefik/v2/pkg/middlewares/auth"
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"github.com/traefik/traefik/v2/pkg/middlewares/buffering"
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"github.com/traefik/traefik/v2/pkg/middlewares/chain"
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"github.com/traefik/traefik/v2/pkg/middlewares/circuitbreaker"
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"github.com/traefik/traefik/v2/pkg/middlewares/compress"
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"github.com/traefik/traefik/v2/pkg/middlewares/customerrors"
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"github.com/traefik/traefik/v2/pkg/middlewares/headers"
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"github.com/traefik/traefik/v2/pkg/middlewares/inflightreq"
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"github.com/traefik/traefik/v2/pkg/middlewares/ipallowlist"
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"github.com/traefik/traefik/v2/pkg/middlewares/ipwhitelist"
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"github.com/traefik/traefik/v2/pkg/middlewares/passtlsclientcert"
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"github.com/traefik/traefik/v2/pkg/middlewares/ratelimiter"
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"github.com/traefik/traefik/v2/pkg/middlewares/redirect"
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"github.com/traefik/traefik/v2/pkg/middlewares/replacepath"
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"github.com/traefik/traefik/v2/pkg/middlewares/replacepathregex"
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"github.com/traefik/traefik/v2/pkg/middlewares/retry"
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"github.com/traefik/traefik/v2/pkg/middlewares/stripprefix"
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"github.com/traefik/traefik/v2/pkg/middlewares/stripprefixregex"
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"github.com/traefik/traefik/v2/pkg/middlewares/tracing"
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"github.com/traefik/traefik/v2/pkg/server/provider"
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)
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type middlewareStackType int
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const (
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middlewareStackKey middlewareStackType = iota
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)
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// Builder the middleware builder.
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type Builder struct {
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configs map[string]*runtime.MiddlewareInfo
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pluginBuilder PluginsBuilder
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serviceBuilder serviceBuilder
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}
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type serviceBuilder interface {
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BuildHTTP(ctx context.Context, serviceName string) (http.Handler, error)
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}
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// NewBuilder creates a new Builder.
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func NewBuilder(configs map[string]*runtime.MiddlewareInfo, serviceBuilder serviceBuilder, pluginBuilder PluginsBuilder) *Builder {
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return &Builder{configs: configs, serviceBuilder: serviceBuilder, pluginBuilder: pluginBuilder}
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}
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// BuildChain creates a middleware chain.
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func (b *Builder) BuildChain(ctx context.Context, middlewares []string) *alice.Chain {
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chain := alice.New()
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for _, name := range middlewares {
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middlewareName := provider.GetQualifiedName(ctx, name)
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chain = chain.Append(func(next http.Handler) (http.Handler, error) {
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constructorContext := provider.AddInContext(ctx, middlewareName)
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if midInf, ok := b.configs[middlewareName]; !ok || midInf.Middleware == nil {
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return nil, fmt.Errorf("middleware %q does not exist", middlewareName)
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}
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var err error
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if constructorContext, err = checkRecursion(constructorContext, middlewareName); err != nil {
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b.configs[middlewareName].AddError(err, true)
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return nil, err
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}
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constructor, err := b.buildConstructor(constructorContext, middlewareName)
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if err != nil {
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b.configs[middlewareName].AddError(err, true)
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return nil, err
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}
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handler, err := constructor(next)
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if err != nil {
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b.configs[middlewareName].AddError(err, true)
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return nil, err
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}
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return handler, nil
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})
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}
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return &chain
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}
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func checkRecursion(ctx context.Context, middlewareName string) (context.Context, error) {
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currentStack, ok := ctx.Value(middlewareStackKey).([]string)
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if !ok {
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currentStack = []string{}
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}
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if inSlice(middlewareName, currentStack) {
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return ctx, fmt.Errorf("could not instantiate middleware %s: recursion detected in %s", middlewareName, strings.Join(append(currentStack, middlewareName), "->"))
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}
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return context.WithValue(ctx, middlewareStackKey, append(currentStack, middlewareName)), nil
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}
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// it is the responsibility of the caller to make sure that b.configs[middlewareName].Middleware exists.
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func (b *Builder) buildConstructor(ctx context.Context, middlewareName string) (alice.Constructor, error) {
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config := b.configs[middlewareName]
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if config == nil || config.Middleware == nil {
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return nil, fmt.Errorf("invalid middleware %q configuration", middlewareName)
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}
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var middleware alice.Constructor
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badConf := errors.New("cannot create middleware: multi-types middleware not supported, consider declaring two different pieces of middleware instead")
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// AddPrefix
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if config.AddPrefix != nil {
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middleware = func(next http.Handler) (http.Handler, error) {
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return addprefix.New(ctx, next, *config.AddPrefix, middlewareName)
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}
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}
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// BasicAuth
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if config.BasicAuth != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return auth.NewBasic(ctx, next, *config.BasicAuth, middlewareName)
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}
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}
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// Buffering
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if config.Buffering != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return buffering.New(ctx, next, *config.Buffering, middlewareName)
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}
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}
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// Chain
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if config.Chain != nil {
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if middleware != nil {
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return nil, badConf
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}
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var qualifiedNames []string
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for _, name := range config.Chain.Middlewares {
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qualifiedNames = append(qualifiedNames, provider.GetQualifiedName(ctx, name))
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}
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config.Chain.Middlewares = qualifiedNames
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middleware = func(next http.Handler) (http.Handler, error) {
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return chain.New(ctx, next, *config.Chain, b, middlewareName)
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}
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}
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// CircuitBreaker
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if config.CircuitBreaker != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return circuitbreaker.New(ctx, next, *config.CircuitBreaker, middlewareName)
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}
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}
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// Compress
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if config.Compress != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return compress.New(ctx, next, *config.Compress, middlewareName)
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}
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}
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// ContentType
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if config.ContentType != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
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if !config.ContentType.AutoDetect {
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rw.Header()["Content-Type"] = nil
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}
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next.ServeHTTP(rw, req)
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}), nil
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}
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}
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// CustomErrors
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if config.Errors != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return customerrors.New(ctx, next, *config.Errors, b.serviceBuilder, middlewareName)
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}
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}
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// DigestAuth
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if config.DigestAuth != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return auth.NewDigest(ctx, next, *config.DigestAuth, middlewareName)
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}
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}
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// ForwardAuth
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if config.ForwardAuth != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return auth.NewForward(ctx, next, *config.ForwardAuth, middlewareName)
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}
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}
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// Headers
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if config.Headers != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return headers.New(ctx, next, *config.Headers, middlewareName)
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}
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}
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// IPWhiteList
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if config.IPWhiteList != nil {
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log.FromContext(ctx).Warn("IPWhiteList is deprecated, please use IPAllowList instead.")
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return ipwhitelist.New(ctx, next, *config.IPWhiteList, middlewareName)
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}
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}
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// IPAllowList
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if config.IPAllowList != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return ipallowlist.New(ctx, next, *config.IPAllowList, middlewareName)
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}
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}
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// InFlightReq
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if config.InFlightReq != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return inflightreq.New(ctx, next, *config.InFlightReq, middlewareName)
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}
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}
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// PassTLSClientCert
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if config.PassTLSClientCert != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return passtlsclientcert.New(ctx, next, *config.PassTLSClientCert, middlewareName)
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}
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}
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// RateLimit
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if config.RateLimit != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return ratelimiter.New(ctx, next, *config.RateLimit, middlewareName)
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}
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}
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// RedirectRegex
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if config.RedirectRegex != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return redirect.NewRedirectRegex(ctx, next, *config.RedirectRegex, middlewareName)
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}
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}
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// RedirectScheme
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if config.RedirectScheme != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return redirect.NewRedirectScheme(ctx, next, *config.RedirectScheme, middlewareName)
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}
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}
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// ReplacePath
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if config.ReplacePath != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return replacepath.New(ctx, next, *config.ReplacePath, middlewareName)
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}
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}
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// ReplacePathRegex
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if config.ReplacePathRegex != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return replacepathregex.New(ctx, next, *config.ReplacePathRegex, middlewareName)
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}
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}
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// Retry
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if config.Retry != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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// TODO missing metrics / accessLog
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return retry.New(ctx, next, *config.Retry, retry.Listeners{}, middlewareName)
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}
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}
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// StripPrefix
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if config.StripPrefix != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return stripprefix.New(ctx, next, *config.StripPrefix, middlewareName)
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}
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}
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// StripPrefixRegex
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if config.StripPrefixRegex != nil {
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if middleware != nil {
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return nil, badConf
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return stripprefixregex.New(ctx, next, *config.StripPrefixRegex, middlewareName)
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}
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}
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// Plugin
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if config.Plugin != nil && !reflect.ValueOf(b.pluginBuilder).IsNil() { // Using "reflect" because "b.pluginBuilder" is an interface.
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if middleware != nil {
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return nil, badConf
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}
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pluginType, rawPluginConfig, err := findPluginConfig(config.Plugin)
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if err != nil {
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return nil, fmt.Errorf("plugin: %w", err)
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}
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plug, err := b.pluginBuilder.Build(pluginType, rawPluginConfig, middlewareName)
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if err != nil {
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return nil, fmt.Errorf("plugin: %w", err)
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}
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middleware = func(next http.Handler) (http.Handler, error) {
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return newTraceablePlugin(ctx, middlewareName, plug, next)
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}
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}
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if middleware == nil {
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return nil, fmt.Errorf("invalid middleware %q configuration: invalid middleware type or middleware does not exist", middlewareName)
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}
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return tracing.Wrap(ctx, middleware), nil
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}
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func inSlice(element string, stack []string) bool {
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for _, value := range stack {
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if value == element {
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return true
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}
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}
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return false
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}
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