Prepare release v2.9.0-rc4

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

.semaphore/semaphore.yml

@@ -64,7 +64,7 @@ blocks:
         - name: GH_VERSION
           value: 1.12.1
         - name: CODENAME
-          value: "beaufort"
+          value: "banon"
         - name: IN_DOCKER
           value: ""
       prologue:

CHANGELOG.md

@@ -1,5 +1,41 @@
-## [v2.9.0-rc1](https://github.com/traefik/traefik/tree/v2.9.0-rc1) (2022-09-14)
-[All Commits](https://github.com/traefik/traefik/compare/v2.8.0-rc1...v2.9.0-rc1)
+## [v2.9.0-rc4](https://github.com/traefik/traefik/tree/v2.9.0-rc4) (2022-09-23)
+[All Commits](https://github.com/traefik/traefik/compare/v2.9.0-rc3...v2.9.0-rc4)
+
+**Bug fixes:**
+- **[acme]** Fix ACME panic ([#9365](https://github.com/traefik/traefik/pull/9365) by [ldez](https://github.com/ldez))
+
+**Documentation:**
+- **[metrics]** Rework metrics overview page ([#9366](https://github.com/traefik/traefik/pull/9366) by [ddtmachado](https://github.com/ddtmachado))
+
+**Misc:**
+- Merge current v2.8 into v2.9 ([#9371](https://github.com/traefik/traefik/pull/9371) by [ldez](https://github.com/ldez))
+- Merge current v2.8 into v2.9 ([#9367](https://github.com/traefik/traefik/pull/9367) by [ldez](https://github.com/ldez))
+- Merge current v2.8 into v2.9 ([#9350](https://github.com/traefik/traefik/pull/9350) by [ldez](https://github.com/ldez))
+
+## [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)
+
+**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))
+
+## [v2.9.0-rc3](https://github.com/traefik/traefik/tree/v2.9.0-rc3) (2022-09-16)
+[All Commits](https://github.com/traefik/traefik/compare/v2.9.0-rc2...v2.9.0-rc3)
+
+**Misc:**
+- Merge current v2.8 into v2.9 ([#9343](https://github.com/traefik/traefik/pull/9343) by [kevinpollet](https://github.com/kevinpollet))
+
+## [v2.9.0-rc1](https://github.com/traefik/traefik/tree/v2.9.0-rc2) (2022-09-14)
+[All Commits](https://github.com/traefik/traefik/compare/v2.8.0-rc1...v2.9.0-rc2)
 
 **Enhancements:**
 - **[acme,tls]** ACME Default Certificate ([#9189](https://github.com/traefik/traefik/pull/9189) by [rtribotte](https://github.com/rtribotte))
@@ -30,6 +66,11 @@
 - Merge current v2.8 into master ([#9146](https://github.com/traefik/traefik/pull/9146) by [kevinpollet](https://github.com/kevinpollet))
 - Merge current v2.8 into master ([#9135](https://github.com/traefik/traefik/pull/9135) by [kevinpollet](https://github.com/kevinpollet))
 
+## [v2.9.0-rc1](https://github.com/traefik/traefik/tree/v2.9.0-rc1) (2022-09-14)
+[All Commits](https://github.com/traefik/traefik/compare/v2.8.0-rc1...v2.9.0-rc1)
+
+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)
 

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/observability/metrics/overview.md

@@ -1,11 +1,11 @@
 ---
 title: "Traefik Metrics Overview"
-description: "Traefik Proxy supports four metrics backend systems: Datadog, InfluxDB, Prometheus, and StatsD. Read the full documentation to get started."
+description: "Traefik Proxy supports these metrics backend systems: Datadog, InfluxDB, Prometheus, and StatsD. Read the full documentation to get started."
 ---
 
 # Metrics
 
-Traefik supports 4 metrics backends:
+Traefik supports these metrics backends:
 
 - [Datadog](./datadog.md)
 - [InfluxDB](./influxdb.md)
@@ -15,569 +15,188 @@ Traefik supports 4 metrics backends:
 
 ## Global Metrics
 
-| Metric                                                                  | DataDog | InfluxDB / InfluxDB2 | Prometheus | StatsD |
-|-------------------------------------------------------------------------|---------|----------------------|------------|--------|
-| [Configuration reloads](#configuration-reloads)                         | ✓       | ✓                    | ✓          | ✓      |
-| [Last Configuration Reload Success](#last-configuration-reload-success) | ✓       | ✓                    | ✓          | ✓      |
-| [TLS certificates expiration](#tls-certificates-expiration)             | ✓       | ✓                    | ✓          | ✓      |
+| Metric                                      | Type    | Description                                             |
+|---------------------------------------------|---------|---------------------------------------------------------|
+| Config reload total                         | Count   | The total count of configuration reloads.               |
+| Config reload last success                  | Gauge   | The timestamp of the last configuration reload success. |
+| TLS certificates not after                  | Gauge   | The expiration date of certificates.                    |
 
-### Configuration Reloads
-
-The total count of configuration reloads.
+```prom tab="Prometheus"
+traefik_config_reloads_total
+traefik_config_last_reload_success
+traefik_tls_certs_not_after
+```
 
 ```dd tab="Datadog"
 config.reload.total
+config.reload.lastSuccessTimestamp
+tls.certs.notAfterTimestamp
 ```
 
 ```influxdb tab="InfluxDB / InfluxDB2"
 traefik.config.reload.total
-```
-
-```prom tab="Prometheus"
-traefik_config_reloads_total
+traefik.config.reload.lastSuccessTimestamp
+traefik.tls.certs.notAfterTimestamp
 ```
 
 ```statsd tab="StatsD"
 # Default prefix: "traefik"
 {prefix}.config.reload.total
-```
-
-### Last Configuration Reload Success
-
-The timestamp of the last configuration reload success.
-
-```dd tab="Datadog"
-config.reload.lastSuccessTimestamp
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.config.reload.lastSuccessTimestamp
-```
-
-```prom tab="Prometheus"
-traefik_config_last_reload_success
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.config.reload.lastSuccessTimestamp
-```
-
-### TLS certificates expiration
-
-The expiration date of certificates.
-
-[Labels](#labels): `cn`, `sans`, `serial`.
-
-```dd tab="Datadog"
-tls.certs.notAfterTimestamp
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.tls.certs.notAfterTimestamp
-```
-
-```prom tab="Prometheus"
-traefik_tls_certs_not_after
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.tls.certs.notAfterTimestamp
 ```
 
 ## EntryPoint Metrics
 
-| Metric                                                    | DataDog | InfluxDB / InfluxDB2 | Prometheus | StatsD |
-|-----------------------------------------------------------|---------|----------------------|------------|--------|
-| [HTTP Requests Count](#http-requests-count)               | ✓       | ✓                    | ✓          | ✓      |
-| [HTTPS Requests Count](#https-requests-count)             | ✓       | ✓                    | ✓          | ✓      |
-| [Request Duration Histogram](#request-duration-histogram) | ✓       | ✓                    | ✓          | ✓      |
-| [Open Connections Count](#open-connections-count)         | ✓       | ✓                    | ✓          | ✓      |
-| [Requests Bytes Count](#requests-bytes-count)             | ✓       | ✓                    | ✓          | ✓      |
-| [Responses Bytes Count](#responses-bytes-count)           | ✓       | ✓                    | ✓          | ✓      |
+| Metric                | Type      | [Labels](#labels)                          | Description                                                         |
+|-----------------------|-----------|--------------------------------------------|---------------------------------------------------------------------|
+| Requests total        | Count     | `code`, `method`, `protocol`, `entrypoint` | The total count of HTTP requests received by an entrypoint.         |
+| Requests TLS total    | Count     | `tls_version`, `tls_cipher`, `entrypoint`  | The total count of HTTPS requests received by an entrypoint.        |
+| Request duration      | Histogram | `code`, `method`, `protocol`, `entrypoint` | Request processing duration histogram on an entrypoint.             |
+| Open connections      | Count     | `method`, `protocol`, `entrypoint`         | The current count of open connections on an entrypoint.             |
+| Requests bytes total  | Count     | `code`, `method`, `protocol`, `entrypoint` | The total size of HTTP requests in bytes handled by an entrypoint.  |
+| Responses bytes total | Count     | `code`, `method`, `protocol`, `entrypoint` | The total size of HTTP responses in bytes handled by an entrypoint. |
 
-### HTTP Requests Count
-
-The total count of HTTP requests received by an entrypoint.
-
-[Labels](#labels): `code`, `method`, `protocol`, `entrypoint`.
+```prom tab="Prometheus"
+traefik_entrypoint_requests_total
+traefik_entrypoint_requests_tls_total
+traefik_entrypoint_request_duration_seconds
+traefik_entrypoint_open_connections
+traefik_entrypoint_requests_bytes_total
+traefik_entrypoint_responses_bytes_total
+```
 
 ```dd tab="Datadog"
 entrypoint.request.total
+entrypoint.request.tls.total
+entrypoint.request.duration
+entrypoint.connections.open
+entrypoint.requests.bytes.total
+entrypoint.responses.bytes.total
 ```
 
 ```influxdb tab="InfluxDB / InfluxDB2"
 traefik.entrypoint.requests.total
-```
-
-```prom tab="Prometheus"
-traefik_entrypoint_requests_total
+traefik.entrypoint.requests.tls.total
+traefik.entrypoint.request.duration
+traefik.entrypoint.connections.open
+traefik.entrypoint.requests.bytes.total
+traefik.entrypoint.responses.bytes.total
 ```
 
 ```statsd tab="StatsD"
 # Default prefix: "traefik"
 {prefix}.entrypoint.request.total
-```
-
-### HTTPS Requests Count
-
-The total count of HTTPS requests received by an entrypoint.
-
-[Labels](#labels): `tls_version`, `tls_cipher`, `entrypoint`.
-
-```dd tab="Datadog"
-entrypoint.request.tls.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.entrypoint.requests.tls.total
-```
-
-```prom tab="Prometheus"
-traefik_entrypoint_requests_tls_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.entrypoint.request.tls.total
-```
-
-### Request Duration Histogram
-
-Request processing duration histogram on an entrypoint.
-
-[Labels](#labels): `code`, `method`, `protocol`, `entrypoint`.
-
-```dd tab="Datadog"
-entrypoint.request.duration
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.entrypoint.request.duration
-```
-
-```prom tab="Prometheus"
-traefik_entrypoint_request_duration_seconds
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.entrypoint.request.duration
-```
-
-### Open Connections Count
-
-The current count of open connections on an entrypoint.
-
-[Labels](#labels): `method`, `protocol`, `entrypoint`.
-
-```dd tab="Datadog"
-entrypoint.connections.open
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.entrypoint.connections.open
-```
-
-```prom tab="Prometheus"
-traefik_entrypoint_open_connections
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.entrypoint.connections.open
-```
-
-### Requests Bytes Count
-
-The total size of HTTP requests in bytes handled by an entrypoint.
-
-[Labels](#labels): `code`, `method`, `protocol`, `entrypoint`.
-
-```dd tab="Datadog"
-entrypoint.requests.bytes.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.entrypoint.requests.bytes.total
-```
-
-```prom tab="Prometheus"
-traefik_entrypoint_requests_bytes_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.entrypoint.requests.bytes.total
-```
-
-### Responses Bytes Count
-
-The total size of HTTP responses in bytes handled by an entrypoint.
-
-[Labels](#labels): `code`, `method`, `protocol`, `entrypoint`.
-
-```dd tab="Datadog"
-entrypoint.responses.bytes.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.entrypoint.responses.bytes.total
-```
-
-```prom tab="Prometheus"
-traefik_entrypoint_responses_bytes_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.entrypoint.responses.bytes.total
 ```
 
 ## Router Metrics
 
-| Metric                                                      | DataDog | InfluxDB / InfluxDB2 | Prometheus | StatsD |
-|-------------------------------------------------------------|---------|----------------------|------------|--------|
-| [HTTP Requests Count](#http-requests-count_1)               | ✓       | ✓                    | ✓          | ✓      |
-| [HTTPS Requests Count](#https-requests-count_1)             | ✓       | ✓                    | ✓          | ✓      |
-| [Request Duration Histogram](#request-duration-histogram_1) | ✓       | ✓                    | ✓          | ✓      |
-| [Open Connections Count](#open-connections-count_1)         | ✓       | ✓                    | ✓          | ✓      |
-| [Requests Bytes Count](#requests-bytes-count_1)             | ✓       | ✓                    | ✓          | ✓      |
-| [Responses Bytes Count](#responses-bytes-count_1)           | ✓       | ✓                    | ✓          | ✓      |
+| Metric                | Type      | [Labels](#labels)                                 | Description                                                    |
+|-----------------------|-----------|---------------------------------------------------|----------------------------------------------------------------|
+| Requests total        | Count     | `code`, `method`, `protocol`, `router`, `service` | The total count of HTTP requests handled by a router.          |
+| Requests TLS total    | Count     | `tls_version`, `tls_cipher`, `router`, `service`  | The total count of HTTPS requests handled by a router.         |
+| Request duration      | Histogram | `code`, `method`, `protocol`, `router`, `service` | Request processing duration histogram on a router.             |
+| Open connections      | Count     | `method`, `protocol`, `router`, `service`         | The current count of open connections on a router.             |
+| Requests bytes total  | Count     | `code`, `method`, `protocol`, `router`, `service` | The total size of HTTP requests in bytes handled by a router.  |
+| Responses bytes total | Count     | `code`, `method`, `protocol`, `router`, `service` | The total size of HTTP responses in bytes handled by a router. |
 
-### HTTP Requests Count
-
-The total count of HTTP requests handled by a router.
-
-[Labels](#labels): `code`, `method`, `protocol`, `router`, `service`.
+```prom tab="Prometheus"
+traefik_router_requests_total
+traefik_router_requests_tls_total
+traefik_router_request_duration_seconds
+traefik_router_open_connections
+traefik_router_requests_bytes_total
+traefik_router_responses_bytes_total
+```
 
 ```dd tab="Datadog"
 router.request.total
+router.request.tls.total
+router.request.duration
+router.connections.open
+router.requests.bytes.total
+router.responses.bytes.total
 ```
 
 ```influxdb tab="InfluxDB / InfluxDB2"
 traefik.router.requests.total
-```
-
-```prom tab="Prometheus"
-traefik_router_requests_total
+traefik.router.requests.tls.total
+traefik.router.request.duration
+traefik.router.connections.open
+traefik.router.requests.bytes.total
+traefik.router.responses.bytes.total
 ```
 
 ```statsd tab="StatsD"
 # Default prefix: "traefik"
 {prefix}.router.request.total
-```
-
-### HTTPS Requests Count
-
-The total count of HTTPS requests handled by a router.
-
-[Labels](#labels): `tls_version`, `tls_cipher`, `router`, `service`.
-
-```dd tab="Datadog"
-router.request.tls.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.router.requests.tls.total
-```
-
-```prom tab="Prometheus"
-traefik_router_requests_tls_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.router.request.tls.total
-```
-
-### Request Duration Histogram
-
-Request processing duration histogram on a router.
-
-[Labels](#labels): `code`, `method`, `protocol`, `router`, `service`.
-
-```dd tab="Datadog"
-router.request.duration
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.router.request.duration
-```
-
-```prom tab="Prometheus"
-traefik_router_request_duration_seconds
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.router.request.duration
-```
-
-### Open Connections Count
-
-The current count of open connections on a router.
-
-[Labels](#labels): `method`, `protocol`, `router`, `service`.
-
-```dd tab="Datadog"
-router.connections.open
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.router.connections.open
-```
-
-```prom tab="Prometheus"
-traefik_router_open_connections
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.router.connections.open
-```
-
-### Requests Bytes Count
-
-The total size of HTTP requests in bytes handled by a router.
-
-[Labels](#labels): `code`, `method`, `protocol`, `router`, `service`.
-
-```dd tab="Datadog"
-router.requests.bytes.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.router.requests.bytes.total
-```
-
-```prom tab="Prometheus"
-traefik_router_requests_bytes_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.router.requests.bytes.total
-```
-
-### Responses Bytes Count
-
-The total size of HTTP responses in bytes handled by a router.
-
-[Labels](#labels): `code`, `method`, `protocol`, `router`, `service`.
-
-```dd tab="Datadog"
-router.responses.bytes.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.router.responses.bytes.total
-```
-
-```prom tab="Prometheus"
-traefik_router_responses_bytes_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.router.responses.bytes.total
 ```
 
 ## Service Metrics
 
-| Metric                                                      | DataDog | InfluxDB / InfluxDB2 | Prometheus | StatsD |
-|-------------------------------------------------------------|---------|----------------------|------------|--------|
-| [HTTP Requests Count](#http-requests-count_2)               | ✓       | ✓                    | ✓          | ✓      |
-| [HTTPS Requests Count](#https-requests-count_2)             | ✓       | ✓                    | ✓          | ✓      |
-| [Request Duration Histogram](#request-duration-histogram_2) | ✓       | ✓                    | ✓          | ✓      |
-| [Open Connections Count](#open-connections-count_2)         | ✓       | ✓                    | ✓          | ✓      |
-| [Requests Retries Count](#requests-retries-count)           | ✓       | ✓                    | ✓          | ✓      |
-| [Service Server UP](#service-server-up)                     | ✓       | ✓                    | ✓          | ✓      |
-| [Requests Bytes Count](#requests-bytes-count_2)             | ✓       | ✓                    | ✓          | ✓      |
-| [Responses outgoing traffic](#responses-bytes-count_2)      | ✓       | ✓                    | ✓          | ✓      |
+| Metric                | Type      | Labels                                  | Description                                                 |
+|-----------------------|-----------|-----------------------------------------|-------------------------------------------------------------|
+| Requests total        | Count     | `code`, `method`, `protocol`, `service` | The total count of HTTP requests processed on a service.    |
+| Requests TLS total    | Count     | `tls_version`, `tls_cipher`, `service`  | The total count of HTTPS requests processed on a service.   |
+| Request duration      | Histogram | `code`, `method`, `protocol`, `service` | Request processing duration histogram on a service.         |
+| Open connections      | Count     | `method`, `protocol`, `service`         | The current count of open connections on a service.         |
+| Retries total         | Count     | `service`                               | The count of requests retries on a service.                 |
+| Server UP             | Gauge     | `service`, `url`                        | Current service's server status, 0 for a down or 1 for up.  |
+| Requests bytes total  | Count     | `code`, `method`, `protocol`, `service` | The total size of requests in bytes received by a service.  |
+| Responses bytes total | Count     | `code`, `method`, `protocol`, `service` | The total size of responses in bytes returned by a service. |
 
-### HTTP Requests Count
-
-The total count of HTTP requests processed on a service.
-
-[Labels](#labels): `code`, `method`, `protocol`, `service`.
+```prom tab="Prometheus"
+traefik_service_requests_total
+traefik_service_requests_tls_total
+traefik_service_request_duration_seconds
+traefik_service_open_connections
+traefik_service_retries_total
+traefik_service_server_up
+traefik_service_requests_bytes_total
+traefik_service_responses_bytes_total
+```
 
 ```dd tab="Datadog"
 service.request.total
+router.service.tls.total
+service.request.duration
+service.connections.open
+service.retries.total
+service.server.up
+service.requests.bytes.total
+service.responses.bytes.total
 ```
 
 ```influxdb tab="InfluxDB / InfluxDB2"
 traefik.service.requests.total
-```
-
-```prom tab="Prometheus"
-traefik_service_requests_total
+traefik.service.requests.tls.total
+traefik.service.request.duration
+traefik.service.connections.open
+traefik.service.retries.total
+traefik.service.server.up
+traefik.service.requests.bytes.total
+traefik.service.responses.bytes.total
 ```
 
 ```statsd tab="StatsD"
 # Default prefix: "traefik"
 {prefix}.service.request.total
-```
-
-### HTTPS Requests Count
-
-The total count of HTTPS requests processed on a service.
-
-[Labels](#labels): `tls_version`, `tls_cipher`, `service`.
-
-```dd tab="Datadog"
-router.service.tls.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.service.requests.tls.total
-```
-
-```prom tab="Prometheus"
-traefik_service_requests_tls_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.service.request.tls.total
-```
-
-### Request Duration Histogram
-
-Request processing duration histogram on a service.
-
-[Labels](#labels): `code`, `method`, `protocol`, `service`.
-
-```dd tab="Datadog"
-service.request.duration
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.service.request.duration
-```
-
-```prom tab="Prometheus"
-traefik_service_request_duration_seconds
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.service.request.duration
-```
-
-### Open Connections Count
-
-The current count of open connections on a service.
-
-[Labels](#labels): `method`, `protocol`, `service`.
-
-```dd tab="Datadog"
-service.connections.open
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.service.connections.open
-```
-
-```prom tab="Prometheus"
-traefik_service_open_connections
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.service.connections.open
-```
-
-### Requests Retries Count
-
-The count of requests retries on a service.
-
-[Labels](#labels): `service`.
-
-```dd tab="Datadog"
-service.retries.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.service.retries.total
-```
-
-```prom tab="Prometheus"
-traefik_service_retries_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.service.retries.total
-```
-
-### Service Server UP
-
-Current service's server status, described by a gauge with a value of 0 for a down server or a value of 1 for an up server.
-
-[Labels](#labels): `service`, `url`.
-
-```dd tab="Datadog"
-service.server.up
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.service.server.up
-```
-
-```prom tab="Prometheus"
-traefik_service_server_up
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.service.server.up
-```
-
-### Requests Bytes Count
-
-The total size of requests in bytes received by a service.
-
-[Labels](#labels): `code`, `method`, `protocol`, `service`.
-
-```dd tab="Datadog"
-service.requests.bytes.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.service.requests.bytes.total
-```
-
-```prom tab="Prometheus"
-traefik_service_requests_bytes_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.service.requests.bytes.total
-```
-
-### Responses Bytes Count
-
-The total size of responses in bytes returned by a service.
-
-[Labels](#labels): `code`, `method`, `protocol`, `service`.
-
-```dd tab="Datadog"
-service.responses.bytes.total
-```
-
-```influxdb tab="InfluxDB / InfluxDB2"
-traefik.service.responses.bytes.total
-```
-
-```prom tab="Prometheus"
-traefik_service_responses_bytes_total
-```
-
-```statsd tab="StatsD"
-# Default prefix: "traefik"
 {prefix}.service.responses.bytes.total
 ```
 

docs/content/providers/ecs.md

@@ -169,6 +169,70 @@ 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/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/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"
 

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/acme/provider.go

@@ -397,7 +397,7 @@ func (p *Provider) resolveDomains(ctx context.Context, domains []string, tlsStor
 				return
 			}
 
-			err = p.addCertificateForDomain(dom, cert.Certificate, cert.PrivateKey, tlsStore)
+			err = p.addCertificateForDomain(dom, cert, tlsStore)
 			if err != nil {
 				logger.WithError(err).Error("Error adding certificate for domain")
 			}
@@ -431,7 +431,7 @@ func (p *Provider) watchNewDomains(ctx context.Context) {
 										return
 									}
 
-									err = p.addCertificateForDomain(dom, cert.Certificate, cert.PrivateKey, traefiktls.DefaultTLSStoreName)
+									err = p.addCertificateForDomain(dom, cert, traefiktls.DefaultTLSStoreName)
 									if err != nil {
 										logger.WithError(err).Error("Error adding certificate for domain")
 									}
@@ -468,7 +468,7 @@ func (p *Provider) watchNewDomains(ctx context.Context) {
 										return
 									}
 
-									err = p.addCertificateForDomain(dom, cert.Certificate, cert.PrivateKey, traefiktls.DefaultTLSStoreName)
+									err = p.addCertificateForDomain(dom, cert, traefiktls.DefaultTLSStoreName)
 									if err != nil {
 										logger.WithError(err).Error("Error adding certificate for domain")
 									}
@@ -535,7 +535,7 @@ func (p *Provider) watchNewDomains(ctx context.Context) {
 							domain.SANs = validDomains[1:]
 						}
 
-						err = p.addCertificateForDomain(domain, cert.Certificate, cert.PrivateKey, traefiktls.DefaultTLSStoreName)
+						err = p.addCertificateForDomain(domain, cert, traefiktls.DefaultTLSStoreName)
 						if err != nil {
 							logger.WithError(err).Error("Error adding certificate for domain")
 						}
@@ -660,11 +660,15 @@ func (p *Provider) removeResolvingDomains(resolvingDomains []string) {
 	}
 }
 
-func (p *Provider) addCertificateForDomain(domain types.Domain, certificate, key []byte, tlsStore string) error {
+func (p *Provider) addCertificateForDomain(domain types.Domain, crt *certificate.Resource, tlsStore string) error {
+	if crt == nil {
+		return nil
+	}
+
 	p.certificatesMu.Lock()
 	defer p.certificatesMu.Unlock()
 
-	cert := Certificate{Certificate: certificate, Key: key, Domain: domain}
+	cert := Certificate{Certificate: crt.Certificate, Key: crt.PrivateKey, Domain: domain}
 
 	certUpdated := false
 	for _, domainsCertificate := range p.certificates {
@@ -828,7 +832,7 @@ func (p *Provider) renewCertificates(ctx context.Context, renewPeriod time.Durat
 			continue
 		}
 
-		err = p.addCertificateForDomain(cert.Domain, renewedCert.Certificate, renewedCert.PrivateKey, cert.Store)
+		err = p.addCertificateForDomain(cert.Domain, renewedCert, cert.Store)
 		if err != nil {
 			logger.WithError(err).Error("Error adding certificate for domain")
 		}

pkg/provider/consulcatalog/config.go

@@ -195,29 +195,27 @@ 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
 }
 
@@ -230,21 +228,23 @@ 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
 }
 
@@ -253,11 +253,6 @@ 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()
@@ -265,17 +260,19 @@ 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),
@@ -2858,6 +2858,57 @@ 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

@@ -196,28 +196,24 @@ 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
 }
 
@@ -226,28 +222,24 @@ 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
 }
 
@@ -256,17 +248,6 @@ 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()
@@ -274,6 +255,14 @@ 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/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

@@ -175,29 +175,27 @@ 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
 }
 
@@ -206,29 +204,27 @@ 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
 }
 
@@ -237,11 +233,6 @@ 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()
@@ -249,19 +240,21 @@ 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/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 v2.8.6
 CurrentRef = "v2.8"
-PreviousRef = "v2.8.4"
+PreviousRef = "v2.8.5"
 BaseBranch = "v2.8"
-FutureCurrentRefName = "v2.8.5"
+FutureCurrentRefName = "v2.8.6"
 
 ThresholdPreviousRef = 10
 ThresholdCurrentRef = 10

script/gcg/traefik-rc-new.toml

@@ -4,11 +4,11 @@ RepositoryName = "traefik"
 OutputType = "file"
 FileName = "traefik_changelog.md"
 
-# example RC2 of v2.8.0
-CurrentRef = "v2.8"
-PreviousRef = "v2.8.0-rc1"
-BaseBranch = "v2.8"
-FutureCurrentRefName = "v2.8.0-rc2"
+# example RC4 of v2.9.0
+CurrentRef = "v2.9"
+PreviousRef = "v2.9.0-rc3"
+BaseBranch = "v2.9"
+FutureCurrentRefName = "v2.9.0-rc4"
 
 ThresholdPreviousRef = 10
 ThresholdCurrentRef = 10