traefik/provider/base_provider.go

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2018-11-14 09:18:03 +00:00
package provider
import (
"bytes"
"strings"
"text/template"
"github.com/BurntSushi/toml"
"github.com/Masterminds/sprig"
"github.com/containous/traefik/config"
"github.com/containous/traefik/log"
"github.com/containous/traefik/types"
)
// BaseProvider should be inherited by providers.
type BaseProvider struct {
Watch bool `description:"Watch provider" export:"true"`
Filename string `description:"Override default configuration template. For advanced users :)" export:"true"`
Constraints types.Constraints `description:"Filter services by constraint, matching with Traefik tags." export:"true"`
Trace bool `description:"Display additional provider logs (if available)." export:"true"`
DebugLogGeneratedTemplate bool `description:"Enable debug logging of generated configuration template." export:"true"`
}
// Init for compatibility reason the BaseProvider implements an empty Init.
func (p *BaseProvider) Init() error {
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return nil
}
// MatchConstraints must match with EVERY single constraint
// returns first constraint that do not match or nil.
func (p *BaseProvider) MatchConstraints(tags []string) (bool, *types.Constraint) {
// if there is no tags and no constraints, filtering is disabled
if len(tags) == 0 && len(p.Constraints) == 0 {
return true, nil
}
for _, constraint := range p.Constraints {
// xor: if ok and constraint.MustMatch are equal, then no tag is currently matching with the constraint
if ok := constraint.MatchConstraintWithAtLeastOneTag(tags); ok != constraint.MustMatch {
return false, constraint
}
}
// If no constraint or every constraints matching
return true, nil
}
// CreateConfiguration creates a provider configuration from content using templating.
func (p *BaseProvider) CreateConfiguration(tmplContent string, funcMap template.FuncMap, templateObjects interface{}) (*config.Configuration, error) {
var defaultFuncMap = sprig.TxtFuncMap()
// tolower is deprecated in favor of sprig's lower function
defaultFuncMap["tolower"] = strings.ToLower
defaultFuncMap["normalize"] = Normalize
defaultFuncMap["split"] = split
for funcID, funcElement := range funcMap {
defaultFuncMap[funcID] = funcElement
}
tmpl := template.New(p.Filename).Funcs(defaultFuncMap)
_, err := tmpl.Parse(tmplContent)
if err != nil {
return nil, err
}
var buffer bytes.Buffer
err = tmpl.Execute(&buffer, templateObjects)
if err != nil {
return nil, err
}
var renderedTemplate = buffer.String()
if p.DebugLogGeneratedTemplate {
log.Debugf("Template content: %s", tmplContent)
log.Debugf("Rendering results: %s", renderedTemplate)
}
return p.DecodeConfiguration(renderedTemplate)
}
// DecodeConfiguration Decodes a *types.Configuration from a content.
func (p *BaseProvider) DecodeConfiguration(content string) (*config.Configuration, error) {
configuration := new(config.Configuration)
if _, err := toml.Decode(content, configuration); err != nil {
return nil, err
}
return configuration, nil
}
func split(sep, s string) []string {
return strings.Split(s, sep)
}