traefik/provider/provider.go

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package provider
import (
"bytes"
"io/ioutil"
"strings"
"text/template"
"unicode"
"github.com/BurntSushi/toml"
"github.com/Masterminds/sprig"
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"github.com/containous/traefik/autogen/gentemplates"
"github.com/containous/traefik/log"
"github.com/containous/traefik/safe"
"github.com/containous/traefik/types"
)
// Provider defines methods of a provider.
type Provider interface {
// Provide allows the provider to provide configurations to traefik
// using the given configuration channel.
Provide(configurationChan chan<- types.ConfigMessage, pool *safe.Pool, constraints types.Constraints) error
}
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// BaseProvider should be inherited by providers
type BaseProvider struct {
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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"`
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TemplateVersion int `description:"Template version." export:"true"`
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DebugLogGeneratedTemplate bool `description:"Enable debug logging of generated configuration template." export:"true"`
}
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// 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) {
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// 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
}
// GetConfiguration return the provider configuration from default template (file or content) or overrode template file
func (p *BaseProvider) GetConfiguration(defaultTemplate string, funcMap template.FuncMap, templateObjects interface{}) (*types.Configuration, error) {
tmplContent, err := p.getTemplateContent(defaultTemplate)
if err != nil {
return nil, err
}
return p.CreateConfiguration(tmplContent, funcMap, templateObjects)
}
// CreateConfiguration create a provider configuration from content using templating
func (p *BaseProvider) CreateConfiguration(tmplContent string, funcMap template.FuncMap, templateObjects interface{}) (*types.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
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for funcID, funcElement := range funcMap {
defaultFuncMap[funcID] = funcElement
}
tmpl := template.New(p.Filename).Funcs(defaultFuncMap)
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_, 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 Decode a *types.Configuration from a content
func (p *BaseProvider) DecodeConfiguration(content string) (*types.Configuration, error) {
configuration := new(types.Configuration)
if _, err := toml.Decode(content, configuration); err != nil {
return nil, err
}
return configuration, nil
}
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func (p *BaseProvider) getTemplateContent(defaultTemplateFile string) (string, error) {
if len(p.Filename) > 0 {
buf, err := ioutil.ReadFile(p.Filename)
if err != nil {
return "", err
}
return string(buf), nil
}
if strings.HasSuffix(defaultTemplateFile, ".tmpl") {
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buf, err := gentemplates.Asset(defaultTemplateFile)
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if err != nil {
return "", err
}
return string(buf), nil
}
return defaultTemplateFile, nil
}
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func split(sep, s string) []string {
return strings.Split(s, sep)
}
// Normalize transform a string that work with the rest of traefik
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// Replace '.' with '-' in quoted keys because of this issue https://github.com/BurntSushi/toml/issues/78
func Normalize(name string) string {
fargs := func(c rune) bool {
return !unicode.IsLetter(c) && !unicode.IsNumber(c)
}
// get function
return strings.Join(strings.FieldsFunc(name, fargs), "-")
}
// ReverseStringSlice invert the order of the given slice of string
func ReverseStringSlice(slice *[]string) {
for i, j := 0, len(*slice)-1; i < j; i, j = i+1, j-1 {
(*slice)[i], (*slice)[j] = (*slice)[j], (*slice)[i]
}
}