Refactor providers and add tests

- Add a `baseProvider` struct with common
- Refactor docker, kv(s) and marathon providers (spliting into small pieces)
- Add unit tests

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

provider/provider.go

@@ -1,6 +1,15 @@
 package provider
 
-import "github.com/emilevauge/traefik/types"
+import (
+	"bytes"
+	"io/ioutil"
+	"strings"
+	"text/template"
+
+	"github.com/BurntSushi/toml"
+	"github.com/emilevauge/traefik/autogen"
+	"github.com/emilevauge/traefik/types"
+)
 
 // Provider defines methods of a provider.
 type Provider interface {
@@ -8,3 +17,51 @@ type Provider interface {
 	// using the given configuration channel.
 	Provide(configurationChan chan<- types.ConfigMessage) error
 }
+
+type baseProvider struct {
+	Watch    bool
+	Filename string
+}
+
+func (p *baseProvider) getConfiguration(defaultTemplateFile string, funcMap template.FuncMap, templateObjects interface{}) (*types.Configuration, error) {
+	var (
+		buf []byte
+		err error
+	)
+	configuration := new(types.Configuration)
+	tmpl := template.New(p.Filename).Funcs(funcMap)
+	if len(p.Filename) > 0 {
+		buf, err = ioutil.ReadFile(p.Filename)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		buf, err = autogen.Asset(defaultTemplateFile)
+		if err != nil {
+			return nil, err
+		}
+	}
+	_, err = tmpl.Parse(string(buf))
+	if err != nil {
+		return nil, err
+	}
+
+	var buffer bytes.Buffer
+	err = tmpl.Execute(&buffer, templateObjects)
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err := toml.Decode(buffer.String(), configuration); err != nil {
+		return nil, err
+	}
+	return configuration, nil
+}
+
+func replace(s1 string, s2 string, s3 string) string {
+	return strings.Replace(s3, s1, s2, -1)
+}
+
+func getEscapedName(name string) string {
+	return strings.Replace(name, "/", "", -1)
+}