chore: fix PyYAML version

Co-authored-by: Kevin Pollet <pollet.kevin@gmail.com>

.goreleaser.yml

@@ -40,6 +40,8 @@ builds:
         goarch: arm64
       - goos: freebsd
         goarch: arm64
+      - goos: windows
+        goarch: arm
 
 changelog:
   skip: true

CHANGELOG.md

@@ -1,3 +1,35 @@
+## [v2.8.8](https://github.com/traefik/traefik/tree/v2.8.8) (2022-09-30)
+[All Commits](https://github.com/traefik/traefik/compare/v2.8.7...v2.8.8)
+
+**Bug fixes:**
+- **[server]** Update golang.org/x/net to latest version ([#9398](https://github.com/traefik/traefik/pull/9398) by [tspearconquest](https://github.com/tspearconquest))
+
+**Documentation:**
+- **[docker]** Fix watch option description for Docker provider ([#9391](https://github.com/traefik/traefik/pull/9391) by [bhuisgen](https://github.com/bhuisgen))
+- **[ecs]** Fix autoDiscoverClusters option documentation for ECS provider ([#9392](https://github.com/traefik/traefik/pull/9392) by [johnpekcan](https://github.com/johnpekcan))
+- **[k8s]** Improve documentation for publishedService and IP options ([#9380](https://github.com/traefik/traefik/pull/9380) by [samip5](https://github.com/samip5))
+
+## [v2.8.7](https://github.com/traefik/traefik/tree/v2.8.7) (2022-09-23)
+[All Commits](https://github.com/traefik/traefik/compare/v2.8.5...v2.8.7)
+
+**Bug fixes:**
+- **[consulcatalog]** Fix UDP loadbalancer tags not being used with Consul Catalog ([#9357](https://github.com/traefik/traefik/pull/9357) by [t3hchipmunk](https://github.com/t3hchipmunk))
+- **[docker,rancher,ecs,provider]** Simplify AddServer algorithm ([#9358](https://github.com/traefik/traefik/pull/9358) by [ldez](https://github.com/ldez))
+- **[plugins]** Allow empty plugin configuration ([#9338](https://github.com/traefik/traefik/pull/9338) by [ldez](https://github.com/ldez))
+- **[rules]** Fix query parameter matching with equal ([#9369](https://github.com/traefik/traefik/pull/9369) by [ldez](https://github.com/ldez))
+- **[server]** Optimize websocket headers handling ([#9360](https://github.com/traefik/traefik/pull/9360) by [juliens](https://github.com/juliens))
+
+**Documentation:**
+- **[ecs]** Add documentation for ECS constraints option ([#9354](https://github.com/traefik/traefik/pull/9354) by [rtribotte](https://github.com/rtribotte))
+- **[k8s/gatewayapi]** Fix link to RouteNamespaces ([#9349](https://github.com/traefik/traefik/pull/9349) by [ldez](https://github.com/ldez))
+- Add documentation for json schema usage to validate config in the FAQ ([#9340](https://github.com/traefik/traefik/pull/9340) by [rtribotte](https://github.com/rtribotte))
+- Add a note on case insensitive regex matching ([#9322](https://github.com/traefik/traefik/pull/9322) by [NEwa-05](https://github.com/NEwa-05))
+
+## [v2.8.6](https://github.com/traefik/traefik/tree/v2.8.6) (2022-09-23)
+[All Commits](https://github.com/traefik/traefik/compare/v2.8.5...v2.8.6)
+
+Release canceled.
+
 ## [v2.8.5](https://github.com/traefik/traefik/tree/v2.8.5) (2022-09-13)
 [All Commits](https://github.com/traefik/traefik/compare/v2.8.4...v2.8.5)
 
@@ -6228,5 +6260,3 @@ Same changelog as v2.0.3.
 - Fix travis tag check [\#422](https://github.com/traefik/traefik/pull/422) ([emilevauge](https://github.com/emilevauge))
 - log info about TOML configuration file using [\#420](https://github.com/traefik/traefik/pull/420) ([cocap10](https://github.com/cocap10))
 - Doc about skipping some integration tests with '-check.f ConsulCatalogSuite' [\#418](https://github.com/traefik/traefik/pull/418) ([samber](https://github.com/samber))
-
-\* *This Change Log was automatically generated by [gcg](https://github.com/ldez/gcg)*

docs/content/getting-started/faq.md

@@ -157,3 +157,27 @@ By default, the following headers are automatically added when proxying requests
 
 For more details,
 please check out the [forwarded header](../routing/entrypoints.md#forwarded-headers) documentation.
+
+## What does the "field not found" error mean?
+
+```shell
+error: field not found, node: -badField-
+```
+
+The "field not found" error occurs, when an unknown property is encountered in the dynamic or static configuration.
+
+One easy way to check whether a configuration file is well-formed, is to validate it with:
+
+- [JSON Schema of the static configuration](https://json.schemastore.org/traefik-v2.json)
+- [JSON Schema of the dynamic configuration](https://json.schemastore.org/traefik-v2-file-provider.json)
+
+## Why are some resources (routers, middlewares, services...) not created/applied?
+
+As a common tip, if a resource is dropped/not created by Traefik after the dynamic configuration was evaluated,
+one should look for an error in the logs.
+
+If found, the error obviously confirms that something went wrong while creating the resource,
+and the message should help in figuring out the mistake(s) in the configuration, and how to fix it.
+
+When using the file provider,
+one easy way to check if the dynamic configuration is well-formed is to validate it with the [JSON Schema of the dynamic configuration](https://json.schemastore.org/traefik-v2-file-provider.json).

docs/content/migration/v2.md

@@ -445,7 +445,7 @@ To enable HTTP/3 on an EntryPoint, please check out the [HTTP/3 configuration](.
 ### Kubernetes Gateway API Provider
 
 In `v2.6`, the [Kubernetes Gateway API provider](../providers/kubernetes-gateway.md) now only supports the version [v1alpha2](https://gateway-api.sigs.k8s.io/v1alpha2/guides/getting-started/) of the specification and 
-[route namespaces](https://gateway-api.sigs.k8s.io/v1alpha2/references/spec/#gateway.networking.k8s.io/v1alpha2.RouteNamespaces) selectors, which requires Traefik to fetch and watch the cluster namespaces.
+[route namespaces](https://gateway-api.sigs.k8s.io/v1alpha2/references/spec/#gateway.networking.k8s.io/v1beta1.RouteNamespaces) selectors, which requires Traefik to fetch and watch the cluster namespaces.
 Therefore, the [RBAC](../reference/dynamic-configuration/kubernetes-gateway.md#rbac) and [CRD](../reference/dynamic-configuration/kubernetes-gateway.md#definitions) definitions must be updated.
 
 ## v2.6.0 to v2.6.1

docs/content/providers/docker.md

@@ -531,7 +531,7 @@ providers:
 
 _Optional, Default=true_
 
-Watch Docker Swarm events.
+Watch Docker events.
 
 ```yaml tab="File (YAML)"
 providers:

docs/content/providers/ecs.md

@@ -65,7 +65,7 @@ _Optional, Default=false_
 
 Search for services in cluster list.
 
-- If set to `true` service discovery is disabled on configured clusters, but enabled for all other clusters.
+- If set to `true` service discovery is enabled for all clusters.
 - If set to `false` service discovery is enabled on configured clusters only.
 
 ```yaml tab="File (YAML)"
@@ -91,6 +91,7 @@ providers:
 _Optional, Default=["default"]_
 
 Search for services in cluster list.
+This option is ignored if `autoDiscoverClusters` is set to `true`.
 
 ```yaml tab="File (YAML)"
 providers:
@@ -137,6 +138,70 @@ providers:
 # ...
 ```
 
+### `constraints`
+
+_Optional, Default=""_
+
+The `constraints` option can be set to an expression that Traefik matches against the container labels (task),
+to determine whether to create any route for that container. 
+If none of the container labels match the expression, no route for that container is created. 
+If the expression is empty, all detected containers are included.
+
+The expression syntax is based on the `Label("key", "value")`, and `LabelRegex("key", "value")` functions,
+as well as the usual boolean logic, as shown in examples below.
+
+??? example "Constraints Expression Examples"
+
+    ```toml
+    # Includes only containers having a label with key `a.label.name` and value `foo`
+    constraints = "Label(`a.label.name`, `foo`)"
+    ```
+
+    ```toml
+    # Excludes containers having any label with key `a.label.name` and value `foo`
+    constraints = "!Label(`a.label.name`, `value`)"
+    ```
+
+    ```toml
+    # With logical AND.
+    constraints = "Label(`a.label.name`, `valueA`) && Label(`another.label.name`, `valueB`)"
+    ```
+
+    ```toml
+    # With logical OR.
+    constraints = "Label(`a.label.name`, `valueA`) || Label(`another.label.name`, `valueB`)"
+    ```
+
+    ```toml
+    # With logical AND and OR, with precedence set by parentheses.
+    constraints = "Label(`a.label.name`, `valueA`) && (Label(`another.label.name`, `valueB`) || Label(`yet.another.label.name`, `valueC`))"
+    ```
+
+    ```toml
+    # Includes only containers having a label with key `a.label.name` and a value matching the `a.+` regular expression.
+    constraints = "LabelRegex(`a.label.name`, `a.+`)"
+    ```
+
+For additional information, refer to [Restrict the Scope of Service Discovery](./overview.md#restrict-the-scope-of-service-discovery).
+
+```yaml tab="File (YAML)"
+providers:
+  ecs:
+    constraints: "Label(`a.label.name`,`foo`)"
+    # ...
+```
+
+```toml tab="File (TOML)"
+[providers.ecs]
+  constraints = "Label(`a.label.name`,`foo`)"
+  # ...
+```
+
+```bash tab="CLI"
+--providers.ecs.constraints=Label(`a.label.name`,`foo`)
+# ...
+```
+
 ### `defaultRule`
 
 _Optional, Default=```Host(`{{ normalize .Name }}`)```_

docs/content/providers/kubernetes-ingress.md

@@ -374,7 +374,7 @@ providers:
 
 _Optional, Default: ""_
 
-IP used for Kubernetes Ingress endpoints.
+This IP will get copied to Ingress `status.loadbalancer.ip`, and currently only supports one IP value (IPv4 or IPv6).
 
 ```yaml tab="File (YAML)"
 providers:
@@ -398,7 +398,9 @@ providers:
 
 _Optional, Default: ""_
 
-Published Kubernetes Service to copy status from.
+The Kubernetes service to copy status from.
+When using third parties tools like External-DNS, this option can be used to copy the service `loadbalancer.status` (containing the service's endpoints IPs) to the ingresses.
+
 Format: `namespace/servicename`.
 
 ```yaml tab="File (YAML)"

docs/content/providers/overview.md

@@ -213,6 +213,7 @@ you can do so in two different ways:
 List of providers that support these features:
 
 - [Docker](./docker.md#exposedbydefault)
+- [ECS](./ecs.md#exposedbydefault)
 - [Consul Catalog](./consul-catalog.md#exposedbydefault)
 - [Nomad](./nomad.md#exposedbydefault)
 - [Rancher](./rancher.md#exposedbydefault)
@@ -223,6 +224,7 @@ List of providers that support these features:
 List of providers that support constraints:
 
 - [Docker](./docker.md#constraints)
+- [ECS](./ecs.md#constraints)
 - [Consul Catalog](./consul-catalog.md#constraints)
 - [Nomad](./nomad.md#constraints)
 - [Rancher](./rancher.md#constraints)

docs/content/reference/static-configuration/cli-ref.md

@@ -562,7 +562,7 @@ TLS key
 Use the ip address from the bound port, rather than from the inner network. (Default: ```false```)
 
 `--providers.docker.watch`:  
-Watch Docker Swarm events. (Default: ```true```)
+Watch Docker events. (Default: ```true```)
 
 `--providers.ecs`:  
 Enable AWS ECS backend with default settings. (Default: ```false```)

docs/content/reference/static-configuration/env-ref.md

@@ -562,7 +562,7 @@ TLS key
 Use the ip address from the bound port, rather than from the inner network. (Default: ```false```)
 
 `TRAEFIK_PROVIDERS_DOCKER_WATCH`:  
-Watch Docker Swarm events. (Default: ```true```)
+Watch Docker events. (Default: ```true```)
 
 `TRAEFIK_PROVIDERS_ECS`:  
 Enable AWS ECS backend with default settings. (Default: ```false```)

docs/content/routing/routers/index.md

@@ -233,18 +233,18 @@ If the rule is verified, the router becomes active, calls middlewares, and then
 
 The table below lists all the available matchers:
 
-| Rule                                                                   | Description                                                                                                    |
-|------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------|
-| ```Headers(`key`, `value`)```                                          | Check if there is a key `key`defined in the headers, with the value `value`                                    |
-| ```HeadersRegexp(`key`, `regexp`)```                                   | Check if there is a key `key`defined in the headers, with a value that matches the regular expression `regexp` |
-| ```Host(`example.com`, ...)```                                         | Check if the request domain (host header value) targets one of the given `domains`.                            |
-| ```HostHeader(`example.com`, ...)```                                   | Same as `Host`, only exists for historical reasons.                                                            |
-| ```HostRegexp(`example.com`, `{subdomain:[a-z]+}.example.com`, ...)``` | Match the request domain. See "Regexp Syntax" below.                                                           |
-| ```Method(`GET`, ...)```                                               | Check if the request method is one of the given `methods` (`GET`, `POST`, `PUT`, `DELETE`, `PATCH`, `HEAD`)    |
-| ```Path(`/path`, `/articles/{cat:[a-z]+}/{id:[0-9]+}`, ...)```         | Match exact request path. See "Regexp Syntax" below.                                                           |
-| ```PathPrefix(`/products/`, `/articles/{cat:[a-z]+}/{id:[0-9]+}`)```   | Match request prefix path. See "Regexp Syntax" below.                                                          |
-| ```Query(`foo=bar`, `bar=baz`)```                                      | Match Query String parameters. It accepts a sequence of key=value pairs.                                       |
-| ```ClientIP(`10.0.0.0/16`, `::1`)```                                   | Match if the request client IP is one of the given IP/CIDR. It accepts IPv4, IPv6 and CIDR formats.            |
+| Rule                                                                                       | Description                                                                                                    |
+|--------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------|
+| ```Headers(`key`, `value`)```                                                              | Check if there is a key `key`defined in the headers, with the value `value`                                    |
+| ```HeadersRegexp(`key`, `regexp`)```                                                       | Check if there is a key `key`defined in the headers, with a value that matches the regular expression `regexp` |
+| ```Host(`example.com`, ...)```                                                             | Check if the request domain (host header value) targets one of the given `domains`.                            |
+| ```HostHeader(`example.com`, ...)```                                                       | Same as `Host`, only exists for historical reasons.                                                            |
+| ```HostRegexp(`example.com`, `{subdomain:[a-z]+}.example.com`, ...)```                     | Match the request domain. See "Regexp Syntax" below.                                                           |
+| ```Method(`GET`, ...)```                                                                   | Check if the request method is one of the given `methods` (`GET`, `POST`, `PUT`, `DELETE`, `PATCH`, `HEAD`)    |
+| ```Path(`/path`, `/articles/{cat:[a-z]+}/{id:[0-9]+}`, ...)```                             | Match exact request path. See "Regexp Syntax" below.                                                           |
+| ```PathPrefix(`/products/`, `/articles/{cat:[a-z]+}/{id:[0-9]+}`)```                       | Match request prefix path. See "Regexp Syntax" below.                                                          |
+| ```Query(`foo=bar`, `bar=baz`)```                                                          | Match Query String parameters. It accepts a sequence of key=value pairs.                                       |
+| ```ClientIP(`10.0.0.0/16`, `::1`)```                                                       | Match if the request client IP is one of the given IP/CIDR. It accepts IPv4, IPv6 and CIDR formats.            |
 
 !!! important "Non-ASCII Domain Names"
 
@@ -259,6 +259,7 @@ The table below lists all the available matchers:
     The regexp name (`name` in the above example) is an arbitrary value, that exists only for historical reasons.
 
     Any `regexp` supported by [Go's regexp package](https://golang.org/pkg/regexp/) may be used.
+    For example, here is a case insensitive path matcher syntax: ```Path(`/{path:(?i:Products)}`)```.
 
 !!! info "Combining Matchers Using Operators and Parenthesis"
 

docs/requirements.txt

@@ -32,7 +32,7 @@ Pygments==2.11.2
 pymdown-extensions==7.0
 pyparsing==2.4.7
 python-dateutil==2.8.2
-PyYAML==6.0
+PyYAML==6.0.1
 pyyaml-env-tag==0.1
 requests==2.25.1
 retrying==1.3.3

go.mod

@@ -67,7 +67,7 @@ require (
 	go.elastic.co/apm v1.13.1
 	go.elastic.co/apm/module/apmot v1.13.1
 	golang.org/x/mod v0.4.2
-	golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e
+	golang.org/x/net v0.0.0-20220927171203-f486391704dc
 	golang.org/x/text v0.3.7
 	golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11
 	golang.org/x/tools v0.1.6-0.20210726203631-07bc1bf47fb2
@@ -313,7 +313,7 @@ require (
 	golang.org/x/lint v0.0.0-20210508222113-6edffad5e616 // indirect
 	golang.org/x/oauth2 v0.0.0-20220223155221-ee480838109b // indirect
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
-	golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e // indirect
+	golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 // indirect
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	google.golang.org/api v0.44.0 // indirect

go.sum

@@ -2239,8 +2239,9 @@ golang.org/x/net v0.0.0-20211020060615-d418f374d309/go.mod h1:9nx3DQGgdP8bBQD5qx
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
 golang.org/x/net v0.0.0-20220225172249-27dd8689420f/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
-golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e h1:TsQ7F31D3bUCLeqPT0u+yjp1guoArKaNKmCr22PYgTQ=
 golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.0.0-20220927171203-f486391704dc h1:FxpXZdoBqT8RjqTy6i1E8nXHhW21wK7ptQ/EPIGxzPQ=
+golang.org/x/net v0.0.0-20220927171203-f486391704dc/go.mod h1:YDH+HFinaLZZlnHAfSS6ZXJJ9M9t4Dl22yv3iI2vPwk=
 golang.org/x/oauth2 v0.0.0-20180724155351-3d292e4d0cdc/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20181017192945-9dcd33a902f4/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@@ -2401,8 +2402,8 @@ golang.org/x/sys v0.0.0-20220114195835-da31bd327af9/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e h1:CsOuNlbOuf0mzxJIefr6Q4uAUetRUwZE4qt7VfzP+xo=
-golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 h1:WIoqL4EROvwiPdUtaip4VcDdpZ4kha7wBWZrbVKCIZg=
+golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210220032956-6a3ed077a48d/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=

integration/helloworld/helloworld.pb.go

@@ -5,9 +5,11 @@
 Package helloworld is a generated protocol buffer package.
 
 It is generated from these files:
+
 	helloworld.proto
 
 It has these top-level messages:
+
 	HelloRequest
 	HelloReply
 	StreamExampleRequest

pkg/muxer/http/mux.go

@@ -237,7 +237,7 @@ func headersRegexp(route *mux.Route, headers ...string) error {
 func query(route *mux.Route, query ...string) error {
 	var queries []string
 	for _, elem := range query {
-		queries = append(queries, strings.Split(elem, "=")...)
+		queries = append(queries, strings.SplitN(elem, "=", 2)...)
 	}
 
 	route.Queries(queries...)

pkg/muxer/http/mux_test.go

@@ -252,6 +252,14 @@ func Test_addRoute(t *testing.T) {
 				"http://localhost/foo?bar=baz":         http.StatusNotFound,
 			},
 		},
+		{
+			desc: "Query with multiple equals",
+			rule: "Query(`foo=b=ar`)",
+			expected: map[string]int{
+				"http://localhost/foo?foo=b=ar": http.StatusOK,
+				"http://localhost/foo?foo=bar":  http.StatusNotFound,
+			},
+		},
 		{
 			desc: "Rule with simple path",
 			rule: `Path("/a")`,

pkg/plugins/middlewares.go

@@ -84,6 +84,9 @@ func (p middlewareBuilder) createConfig(config map[string]interface{}) (reflect.
 	}
 
 	vConfig := results[0]
+	if len(config) == 0 {
+		return vConfig, nil
+	}
 
 	cfg := &mapstructure.DecoderConfig{
 		DecodeHook:       mapstructure.StringToSliceHookFunc(","),

pkg/provider/consulcatalog/config.go

@@ -198,29 +198,27 @@ func (p *Provider) addServerTCP(item itemData, loadBalancer *dynamic.TCPServersL
 		return errors.New("load-balancer is not defined")
 	}
 
-	var port string
-	if len(loadBalancer.Servers) > 0 {
-		port = loadBalancer.Servers[0].Port
-	}
-
 	if len(loadBalancer.Servers) == 0 {
 		loadBalancer.Servers = []dynamic.TCPServer{{}}
 	}
 
-	if item.Port != "" && port == "" {
-		port = item.Port
-	}
-	loadBalancer.Servers[0].Port = ""
-
-	if port == "" {
-		return errors.New("port is missing")
-	}
-
 	if item.Address == "" {
 		return errors.New("address is missing")
 	}
 
+	port := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
+	if port == "" {
+		port = item.Port
+	}
+
+	if port == "" {
+		return errors.New("port is missing")
+	}
+
 	loadBalancer.Servers[0].Address = net.JoinHostPort(item.Address, port)
+
 	return nil
 }
 
@@ -233,21 +231,23 @@ func (p *Provider) addServerUDP(item itemData, loadBalancer *dynamic.UDPServersL
 		loadBalancer.Servers = []dynamic.UDPServer{{}}
 	}
 
-	var port string
-	if item.Port != "" {
+	if item.Address == "" {
+		return errors.New("address is missing")
+	}
+
+	port := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
+	if port == "" {
 		port = item.Port
-		loadBalancer.Servers[0].Port = ""
 	}
 
 	if port == "" {
 		return errors.New("port is missing")
 	}
 
-	if item.Address == "" {
-		return errors.New("address is missing")
-	}
-
 	loadBalancer.Servers[0].Address = net.JoinHostPort(item.Address, port)
+
 	return nil
 }
 
@@ -256,11 +256,6 @@ func (p *Provider) addServer(item itemData, loadBalancer *dynamic.ServersLoadBal
 		return errors.New("load-balancer is not defined")
 	}
 
-	var port string
-	if len(loadBalancer.Servers) > 0 {
-		port = loadBalancer.Servers[0].Port
-	}
-
 	if len(loadBalancer.Servers) == 0 {
 		server := dynamic.Server{}
 		server.SetDefaults()
@@ -268,17 +263,19 @@ func (p *Provider) addServer(item itemData, loadBalancer *dynamic.ServersLoadBal
 		loadBalancer.Servers = []dynamic.Server{server}
 	}
 
-	if item.Port != "" && port == "" {
-		port = item.Port
+	if item.Address == "" {
+		return errors.New("address is missing")
 	}
+
+	port := loadBalancer.Servers[0].Port
 	loadBalancer.Servers[0].Port = ""
 
 	if port == "" {
-		return errors.New("port is missing")
+		port = item.Port
 	}
 
-	if item.Address == "" {
-		return errors.New("address is missing")
+	if port == "" {
+		return errors.New("port is missing")
 	}
 
 	scheme := loadBalancer.Servers[0].Scheme

pkg/provider/consulcatalog/config_test.go

@@ -2220,7 +2220,7 @@ func Test_buildConfiguration(t *testing.T) {
 					Labels: map[string]string{
 						"traefik.tcp.routers.foo.rule":                      "HostSNI(`foo.bar`)",
 						"traefik.tcp.routers.foo.tls.options":               "foo",
-						"traefik.tcp.services.foo.loadbalancer.server.port": "80",
+						"traefik.tcp.services.foo.loadbalancer.server.port": "8080",
 					},
 					Address: "127.0.0.1",
 					Port:    "80",
@@ -2244,7 +2244,7 @@ func Test_buildConfiguration(t *testing.T) {
 							LoadBalancer: &dynamic.TCPServersLoadBalancer{
 								Servers: []dynamic.TCPServer{
 									{
-										Address: "127.0.0.1:80",
+										Address: "127.0.0.1:8080",
 									},
 								},
 								TerminationDelay: Int(100),
@@ -2611,6 +2611,57 @@ func Test_buildConfiguration(t *testing.T) {
 				},
 			},
 		},
+		{
+			desc:         "UDP service with labels only",
+			ConnectAware: true,
+			items: []itemData{
+				{
+					ID:         "1",
+					Node:       "Node1",
+					Datacenter: "dc1",
+					Name:       "Test",
+					Namespace:  "ns",
+					Labels: map[string]string{
+						"traefik.udp.routers.test-udp-label.service":                           "test-udp-label-service",
+						"traefik.udp.routers.test-udp-label.entryPoints":                       "udp",
+						"traefik.udp.services.test-udp-label-service.loadBalancer.server.port": "21116",
+					},
+					Address: "127.0.0.1",
+					Port:    "80",
+					Status:  api.HealthPassing,
+				},
+			},
+			expected: &dynamic.Configuration{
+				TCP: &dynamic.TCPConfiguration{
+					Routers:     map[string]*dynamic.TCPRouter{},
+					Middlewares: map[string]*dynamic.TCPMiddleware{},
+					Services:    map[string]*dynamic.TCPService{},
+				},
+				UDP: &dynamic.UDPConfiguration{
+					Routers: map[string]*dynamic.UDPRouter{
+						"test-udp-label": {
+							EntryPoints: []string{"udp"},
+							Service:     "test-udp-label-service",
+						},
+					},
+					Services: map[string]*dynamic.UDPService{
+						"test-udp-label-service": {
+							LoadBalancer: &dynamic.UDPServersLoadBalancer{
+								Servers: []dynamic.UDPServer{
+									{Address: "127.0.0.1:21116"},
+								},
+							},
+						},
+					},
+				},
+				HTTP: &dynamic.HTTPConfiguration{
+					Routers:           map[string]*dynamic.Router{},
+					Middlewares:       map[string]*dynamic.Middleware{},
+					Services:          map[string]*dynamic.Service{},
+					ServersTransports: map[string]*dynamic.ServersTransport{},
+				},
+			},
+		},
 	}
 
 	for _, test := range testCases {

pkg/provider/docker/config.go

@@ -187,28 +187,24 @@ func (p *Provider) addServerTCP(ctx context.Context, container dockerData, loadB
 		return errors.New("load-balancer is not defined")
 	}
 
-	var serverPort string
-	if len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
-		loadBalancer.Servers[0].Port = ""
+	if len(loadBalancer.Servers) == 0 {
+		loadBalancer.Servers = []dynamic.TCPServer{{}}
 	}
 
+	serverPort := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
 	ip, port, err := p.getIPPort(ctx, container, serverPort)
 	if err != nil {
 		return err
 	}
 
-	if len(loadBalancer.Servers) == 0 {
-		server := dynamic.TCPServer{}
-
-		loadBalancer.Servers = []dynamic.TCPServer{server}
-	}
-
 	if port == "" {
 		return errors.New("port is missing")
 	}
 
 	loadBalancer.Servers[0].Address = net.JoinHostPort(ip, port)
+
 	return nil
 }
 
@@ -217,28 +213,24 @@ func (p *Provider) addServerUDP(ctx context.Context, container dockerData, loadB
 		return errors.New("load-balancer is not defined")
 	}
 
-	var serverPort string
-	if len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
-		loadBalancer.Servers[0].Port = ""
+	if len(loadBalancer.Servers) == 0 {
+		loadBalancer.Servers = []dynamic.UDPServer{{}}
 	}
 
+	serverPort := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
 	ip, port, err := p.getIPPort(ctx, container, serverPort)
 	if err != nil {
 		return err
 	}
 
-	if len(loadBalancer.Servers) == 0 {
-		server := dynamic.UDPServer{}
-
-		loadBalancer.Servers = []dynamic.UDPServer{server}
-	}
-
 	if port == "" {
 		return errors.New("port is missing")
 	}
 
 	loadBalancer.Servers[0].Address = net.JoinHostPort(ip, port)
+
 	return nil
 }
 
@@ -247,17 +239,6 @@ func (p *Provider) addServer(ctx context.Context, container dockerData, loadBala
 		return errors.New("load-balancer is not defined")
 	}
 
-	var serverPort string
-	if len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
-		loadBalancer.Servers[0].Port = ""
-	}
-
-	ip, port, err := p.getIPPort(ctx, container, serverPort)
-	if err != nil {
-		return err
-	}
-
 	if len(loadBalancer.Servers) == 0 {
 		server := dynamic.Server{}
 		server.SetDefaults()
@@ -265,6 +246,14 @@ func (p *Provider) addServer(ctx context.Context, container dockerData, loadBala
 		loadBalancer.Servers = []dynamic.Server{server}
 	}
 
+	serverPort := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
+	ip, port, err := p.getIPPort(ctx, container, serverPort)
+	if err != nil {
+		return err
+	}
+
 	if port == "" {
 		return errors.New("port is missing")
 	}

pkg/provider/docker/docker.go

@@ -49,7 +49,7 @@ var _ provider.Provider = (*Provider)(nil)
 // Provider holds configurations of the provider.
 type Provider struct {
 	Constraints             string           `description:"Constraints is an expression that Traefik matches against the container's labels to determine whether to create any route for that container." json:"constraints,omitempty" toml:"constraints,omitempty" yaml:"constraints,omitempty" export:"true"`
-	Watch                   bool             `description:"Watch Docker Swarm events." json:"watch,omitempty" toml:"watch,omitempty" yaml:"watch,omitempty" export:"true"`
+	Watch                   bool             `description:"Watch Docker events." json:"watch,omitempty" toml:"watch,omitempty" yaml:"watch,omitempty" export:"true"`
 	Endpoint                string           `description:"Docker server endpoint. Can be a tcp or a unix socket endpoint." json:"endpoint,omitempty" toml:"endpoint,omitempty" yaml:"endpoint,omitempty"`
 	DefaultRule             string           `description:"Default rule." json:"defaultRule,omitempty" toml:"defaultRule,omitempty" yaml:"defaultRule,omitempty"`
 	TLS                     *types.ClientTLS `description:"Enable Docker TLS support." json:"tls,omitempty" toml:"tls,omitempty" yaml:"tls,omitempty" export:"true"`

pkg/provider/ecs/config.go

@@ -185,7 +185,7 @@ func (p *Provider) filterInstance(ctx context.Context, instance ecsInstance) boo
 
 	matches, err := constraints.MatchLabels(instance.Labels, p.Constraints)
 	if err != nil {
-		logger.Errorf("Error matching constraints expression: %v", err)
+		logger.Errorf("Error matching constraint expression: %v", err)
 		return false
 	}
 	if !matches {
@@ -201,28 +201,24 @@ func (p *Provider) addServerTCP(instance ecsInstance, loadBalancer *dynamic.TCPS
 		return errors.New("load-balancer is not defined")
 	}
 
-	var serverPort string
-	if len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
-		loadBalancer.Servers[0].Port = ""
+	if len(loadBalancer.Servers) == 0 {
+		loadBalancer.Servers = []dynamic.TCPServer{{}}
 	}
 
+	serverPort := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
 	ip, port, err := p.getIPPort(instance, serverPort)
 	if err != nil {
 		return err
 	}
 
-	if len(loadBalancer.Servers) == 0 {
-		server := dynamic.TCPServer{}
-
-		loadBalancer.Servers = []dynamic.TCPServer{server}
-	}
-
 	if port == "" {
 		return errors.New("port is missing")
 	}
 
 	loadBalancer.Servers[0].Address = net.JoinHostPort(ip, port)
+
 	return nil
 }
 
@@ -231,28 +227,24 @@ func (p *Provider) addServerUDP(instance ecsInstance, loadBalancer *dynamic.UDPS
 		return errors.New("load-balancer is not defined")
 	}
 
-	var serverPort string
-	if len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
-		loadBalancer.Servers[0].Port = ""
+	if len(loadBalancer.Servers) == 0 {
+		loadBalancer.Servers = []dynamic.UDPServer{{}}
 	}
 
+	serverPort := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
 	ip, port, err := p.getIPPort(instance, serverPort)
 	if err != nil {
 		return err
 	}
 
-	if len(loadBalancer.Servers) == 0 {
-		server := dynamic.UDPServer{}
-
-		loadBalancer.Servers = []dynamic.UDPServer{server}
-	}
-
 	if port == "" {
 		return errors.New("port is missing")
 	}
 
 	loadBalancer.Servers[0].Address = net.JoinHostPort(ip, port)
+
 	return nil
 }
 
@@ -261,17 +253,6 @@ func (p *Provider) addServer(instance ecsInstance, loadBalancer *dynamic.Servers
 		return errors.New("load-balancer is not defined")
 	}
 
-	var serverPort string
-	if len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
-		loadBalancer.Servers[0].Port = ""
-	}
-
-	ip, port, err := p.getIPPort(instance, serverPort)
-	if err != nil {
-		return err
-	}
-
 	if len(loadBalancer.Servers) == 0 {
 		server := dynamic.Server{}
 		server.SetDefaults()
@@ -279,6 +260,14 @@ func (p *Provider) addServer(instance ecsInstance, loadBalancer *dynamic.Servers
 		loadBalancer.Servers = []dynamic.Server{server}
 	}
 
+	serverPort := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
+	ip, port, err := p.getIPPort(instance, serverPort)
+	if err != nil {
+		return err
+	}
+
 	if port == "" {
 		return errors.New("port is missing")
 	}

pkg/provider/nomad/config.go

@@ -172,29 +172,27 @@ func (p *Provider) addServerTCP(i item, lb *dynamic.TCPServersLoadBalancer) erro
 		return errors.New("load-balancer is missing")
 	}
 
-	var port string
-	if len(lb.Servers) > 0 {
-		port = lb.Servers[0].Port
-	}
-
 	if len(lb.Servers) == 0 {
 		lb.Servers = []dynamic.TCPServer{{}}
 	}
 
-	if i.Port != 0 && port == "" {
-		port = strconv.Itoa(i.Port)
-	}
-	lb.Servers[0].Port = ""
-
-	if port == "" {
-		return errors.New("port is missing")
-	}
-
 	if i.Address == "" {
 		return errors.New("address is missing")
 	}
 
+	port := lb.Servers[0].Port
+	lb.Servers[0].Port = ""
+
+	if port == "" && i.Port > 0 {
+		port = strconv.Itoa(i.Port)
+	}
+
+	if port == "" {
+		return errors.New("port is missing")
+	}
+
 	lb.Servers[0].Address = net.JoinHostPort(i.Address, port)
+
 	return nil
 }
 
@@ -203,29 +201,27 @@ func (p *Provider) addServerUDP(i item, lb *dynamic.UDPServersLoadBalancer) erro
 		return errors.New("load-balancer is missing")
 	}
 
-	var port string
-	if len(lb.Servers) > 0 {
-		port = lb.Servers[0].Port
-	}
-
 	if len(lb.Servers) == 0 {
 		lb.Servers = []dynamic.UDPServer{{}}
 	}
 
-	if i.Port != 0 && port == "" {
-		port = strconv.Itoa(i.Port)
-	}
-	lb.Servers[0].Port = ""
-
-	if port == "" {
-		return errors.New("port is missing")
-	}
-
 	if i.Address == "" {
 		return errors.New("address is missing")
 	}
 
+	port := lb.Servers[0].Port
+	lb.Servers[0].Port = ""
+
+	if port == "" && i.Port > 0 {
+		port = strconv.Itoa(i.Port)
+	}
+
+	if port == "" {
+		return errors.New("port is missing")
+	}
+
 	lb.Servers[0].Address = net.JoinHostPort(i.Address, port)
+
 	return nil
 }
 
@@ -234,11 +230,6 @@ func (p *Provider) addServer(i item, lb *dynamic.ServersLoadBalancer) error {
 		return errors.New("load-balancer is missing")
 	}
 
-	var port string
-	if len(lb.Servers) > 0 {
-		port = lb.Servers[0].Port
-	}
-
 	if len(lb.Servers) == 0 {
 		server := dynamic.Server{}
 		server.SetDefaults()
@@ -246,19 +237,21 @@ func (p *Provider) addServer(i item, lb *dynamic.ServersLoadBalancer) error {
 		lb.Servers = []dynamic.Server{server}
 	}
 
-	if i.Port != 0 && port == "" {
+	if i.Address == "" {
+		return errors.New("address is missing")
+	}
+
+	port := lb.Servers[0].Port
+	lb.Servers[0].Port = ""
+
+	if port == "" && i.Port > 0 {
 		port = strconv.Itoa(i.Port)
 	}
-	lb.Servers[0].Port = ""
 
 	if port == "" {
 		return errors.New("port is missing")
 	}
 
-	if i.Address == "" {
-		return errors.New("address is missing")
-	}
-
 	scheme := lb.Servers[0].Scheme
 	lb.Servers[0].Scheme = ""
 	lb.Servers[0].URL = fmt.Sprintf("%s://%s", scheme, net.JoinHostPort(i.Address, port))

pkg/provider/rancher/config.go

@@ -160,7 +160,7 @@ func (p *Provider) keepService(ctx context.Context, service rancherData) bool {
 
 	matches, err := constraints.MatchLabels(service.Labels, p.Constraints)
 	if err != nil {
-		logger.Errorf("Error matching constraints expression: %v", err)
+		logger.Errorf("Error matching constraint expression: %v", err)
 		return false
 	}
 	if !matches {
@@ -185,23 +185,19 @@ func (p *Provider) keepService(ctx context.Context, service rancherData) bool {
 func (p *Provider) addServerTCP(ctx context.Context, service rancherData, loadBalancer *dynamic.TCPServersLoadBalancer) error {
 	log.FromContext(ctx).Debugf("Trying to add servers for service  %s \n", service.Name)
 
-	serverPort := ""
-
-	if loadBalancer != nil && len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
+	if loadBalancer == nil {
+		return errors.New("load-balancer is not defined")
 	}
 
-	port := getServicePort(service)
-
 	if len(loadBalancer.Servers) == 0 {
-		server := dynamic.TCPServer{}
-
-		loadBalancer.Servers = []dynamic.TCPServer{server}
+		loadBalancer.Servers = []dynamic.TCPServer{{}}
 	}
 
-	if serverPort != "" {
-		port = serverPort
-		loadBalancer.Servers[0].Port = ""
+	port := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
+	if port == "" {
+		port = getServicePort(service)
 	}
 
 	if port == "" {
@@ -216,29 +212,26 @@ func (p *Provider) addServerTCP(ctx context.Context, service rancherData, loadBa
 	}
 
 	loadBalancer.Servers = servers
+
 	return nil
 }
 
 func (p *Provider) addServerUDP(ctx context.Context, service rancherData, loadBalancer *dynamic.UDPServersLoadBalancer) error {
 	log.FromContext(ctx).Debugf("Trying to add servers for service  %s \n", service.Name)
 
-	serverPort := ""
-
-	if loadBalancer != nil && len(loadBalancer.Servers) > 0 {
-		serverPort = loadBalancer.Servers[0].Port
+	if loadBalancer == nil {
+		return errors.New("load-balancer is not defined")
 	}
 
-	port := getServicePort(service)
-
 	if len(loadBalancer.Servers) == 0 {
-		server := dynamic.UDPServer{}
-
-		loadBalancer.Servers = []dynamic.UDPServer{server}
+		loadBalancer.Servers = []dynamic.UDPServer{{}}
 	}
 
-	if serverPort != "" {
-		port = serverPort
-		loadBalancer.Servers[0].Port = ""
+	port := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
+	if port == "" {
+		port = getServicePort(service)
 	}
 
 	if port == "" {
@@ -253,14 +246,16 @@ func (p *Provider) addServerUDP(ctx context.Context, service rancherData, loadBa
 	}
 
 	loadBalancer.Servers = servers
+
 	return nil
 }
 
 func (p *Provider) addServers(ctx context.Context, service rancherData, loadBalancer *dynamic.ServersLoadBalancer) error {
 	log.FromContext(ctx).Debugf("Trying to add servers for service  %s \n", service.Name)
 
-	serverPort := getLBServerPort(loadBalancer)
-	port := getServicePort(service)
+	if loadBalancer == nil {
+		return errors.New("load-balancer is not defined")
+	}
 
 	if len(loadBalancer.Servers) == 0 {
 		server := dynamic.Server{}
@@ -269,9 +264,11 @@ func (p *Provider) addServers(ctx context.Context, service rancherData, loadBala
 		loadBalancer.Servers = []dynamic.Server{server}
 	}
 
-	if serverPort != "" {
-		port = serverPort
-		loadBalancer.Servers[0].Port = ""
+	port := loadBalancer.Servers[0].Port
+	loadBalancer.Servers[0].Port = ""
+
+	if port == "" {
+		port = getServicePort(service)
 	}
 
 	if port == "" {
@@ -286,14 +283,8 @@ func (p *Provider) addServers(ctx context.Context, service rancherData, loadBala
 	}
 
 	loadBalancer.Servers = servers
-	return nil
-}
 
-func getLBServerPort(loadBalancer *dynamic.ServersLoadBalancer) string {
-	if loadBalancer != nil && len(loadBalancer.Servers) > 0 {
-		return loadBalancer.Servers[0].Port
-	}
-	return ""
+	return nil
 }
 
 func getServicePort(data rancherData) string {

pkg/server/middleware/plugins.go

@@ -2,7 +2,6 @@ package middleware
 
 import (
 	"errors"
-	"fmt"
 
 	"github.com/traefik/traefik/v2/pkg/config/dynamic"
 	"github.com/traefik/traefik/v2/pkg/plugins"
@@ -30,9 +29,5 @@ func findPluginConfig(rawConfig map[string]dynamic.PluginConf) (string, map[stri
 		return "", nil, errors.New("missing plugin type")
 	}
 
-	if len(rawPluginConfig) == 0 {
-		return "", nil, fmt.Errorf("missing plugin configuration: %s", pluginType)
-	}
-
 	return pluginType, rawPluginConfig, nil
 }

pkg/server/server_signals_windows.go

@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package server

pkg/server/service/proxy.go

@@ -15,6 +15,7 @@ import (
 	ptypes "github.com/traefik/paerser/types"
 	"github.com/traefik/traefik/v2/pkg/config/dynamic"
 	"github.com/traefik/traefik/v2/pkg/log"
+	"golang.org/x/net/http/httpguts"
 )
 
 // StatusClientClosedRequest non-standard HTTP status code for client disconnection.
@@ -67,16 +68,18 @@ func buildProxy(passHostHeader *bool, responseForwarding *dynamic.ResponseForwar
 			// some servers need Sec-WebSocket-Key, Sec-WebSocket-Extensions, Sec-WebSocket-Accept,
 			// Sec-WebSocket-Protocol and Sec-WebSocket-Version to be case-sensitive.
 			// https://tools.ietf.org/html/rfc6455#page-20
-			outReq.Header["Sec-WebSocket-Key"] = outReq.Header["Sec-Websocket-Key"]
-			outReq.Header["Sec-WebSocket-Extensions"] = outReq.Header["Sec-Websocket-Extensions"]
-			outReq.Header["Sec-WebSocket-Accept"] = outReq.Header["Sec-Websocket-Accept"]
-			outReq.Header["Sec-WebSocket-Protocol"] = outReq.Header["Sec-Websocket-Protocol"]
-			outReq.Header["Sec-WebSocket-Version"] = outReq.Header["Sec-Websocket-Version"]
-			delete(outReq.Header, "Sec-Websocket-Key")
-			delete(outReq.Header, "Sec-Websocket-Extensions")
-			delete(outReq.Header, "Sec-Websocket-Accept")
-			delete(outReq.Header, "Sec-Websocket-Protocol")
-			delete(outReq.Header, "Sec-Websocket-Version")
+			if isWebSocketUpgrade(outReq) {
+				outReq.Header["Sec-WebSocket-Key"] = outReq.Header["Sec-Websocket-Key"]
+				outReq.Header["Sec-WebSocket-Extensions"] = outReq.Header["Sec-Websocket-Extensions"]
+				outReq.Header["Sec-WebSocket-Accept"] = outReq.Header["Sec-Websocket-Accept"]
+				outReq.Header["Sec-WebSocket-Protocol"] = outReq.Header["Sec-Websocket-Protocol"]
+				outReq.Header["Sec-WebSocket-Version"] = outReq.Header["Sec-Websocket-Version"]
+				delete(outReq.Header, "Sec-Websocket-Key")
+				delete(outReq.Header, "Sec-Websocket-Extensions")
+				delete(outReq.Header, "Sec-Websocket-Accept")
+				delete(outReq.Header, "Sec-Websocket-Protocol")
+				delete(outReq.Header, "Sec-Websocket-Version")
+			}
 		},
 		Transport:     roundTripper,
 		FlushInterval: time.Duration(flushInterval),
@@ -112,6 +115,14 @@ func buildProxy(passHostHeader *bool, responseForwarding *dynamic.ResponseForwar
 	return proxy, nil
 }
 
+func isWebSocketUpgrade(req *http.Request) bool {
+	if !httpguts.HeaderValuesContainsToken(req.Header["Connection"], "Upgrade") {
+		return false
+	}
+
+	return strings.EqualFold(req.Header.Get("Upgrade"), "websocket")
+}
+
 func statusText(statusCode int) string {
 	if statusCode == StatusClientClosedRequest {
 		return StatusClientClosedRequestText

script/gcg/traefik-bugfix.toml

@@ -4,11 +4,11 @@ RepositoryName = "traefik"
 OutputType = "file"
 FileName = "traefik_changelog.md"
 
-# example new bugfix v2.8.5
+# example new bugfix v2.8.8
 CurrentRef = "v2.8"
-PreviousRef = "v2.8.4"
+PreviousRef = "v2.8.7"
 BaseBranch = "v2.8"
-FutureCurrentRefName = "v2.8.5"
+FutureCurrentRefName = "v2.8.8"
 
 ThresholdPreviousRef = 10
 ThresholdCurrentRef = 10