Merge current v2.8 into v2.9

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/routing/routers/index.md

@@ -234,7 +234,7 @@ 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`.                            |
@@ -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/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/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
 }