/
koanf_provider_filtered_file.go
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/
koanf_provider_filtered_file.go
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package configuration
import (
"bytes"
"encoding/base64"
"errors"
"fmt"
"os"
"path/filepath"
"strings"
"text/template"
"github.com/sirupsen/logrus"
"github.com/authelia/authelia/v4/internal/logging"
"github.com/authelia/authelia/v4/internal/templates"
)
// FilteredFile implements a koanf.Provider.
type FilteredFile struct {
path string
filters []BytesFilter
}
// FilteredFileProvider returns a koanf.Provider which provides filtered file output.
func FilteredFileProvider(path string, filters ...BytesFilter) *FilteredFile {
return &FilteredFile{
path: filepath.Clean(path),
filters: filters,
}
}
// ReadBytes reads the contents of a file on disk, passes it through any configured filters, and returns the bytes.
func (f *FilteredFile) ReadBytes() (data []byte, err error) {
if data, err = os.ReadFile(f.path); err != nil {
return nil, err
}
if len(data) == 0 || len(f.filters) == 0 {
return data, nil
}
for _, filter := range f.filters {
if data, err = filter(data); err != nil {
return nil, err
}
}
return data, nil
}
// Read is not supported by the filtered file koanf.Provider.
func (f *FilteredFile) Read() (map[string]any, error) {
return nil, errors.New("filtered file provider does not support this method")
}
// BytesFilter describes a func used to filter files.
type BytesFilter func(in []byte) (out []byte, err error)
// NewFileFiltersDefault returns the default list of BytesFilter.
func NewFileFiltersDefault() []BytesFilter {
return []BytesFilter{
NewExpandEnvFileFilter(),
NewTemplateFileFilter(),
}
}
// NewFileFilters returns a list of BytesFilter provided they are valid.
func NewFileFilters(names []string) (filters []BytesFilter, err error) {
filters = make([]BytesFilter, len(names))
filterMap := map[string]int{}
for i, name := range names {
name = strings.ToLower(name)
switch name {
case "template":
filters[i] = NewTemplateFileFilter()
case "expand-env":
filters[i] = NewExpandEnvFileFilter()
default:
return nil, fmt.Errorf("invalid filter named '%s'", name)
}
if _, ok := filterMap[name]; ok {
return nil, fmt.Errorf("duplicate filter named '%s'", name)
} else {
filterMap[name] = 1
}
}
return filters, nil
}
// NewExpandEnvFileFilter is a BytesFilter which passes the bytes through os.ExpandEnv.
func NewExpandEnvFileFilter() BytesFilter {
log := logging.Logger()
return func(in []byte) (out []byte, err error) {
out = []byte(os.Expand(string(in), templates.FuncGetEnv))
if log.Level >= logrus.TraceLevel {
log.
WithField("content", base64.RawStdEncoding.EncodeToString(out)).
Trace("Expanded Env File Filter completed successfully")
}
return out, nil
}
}
// NewTemplateFileFilter is a BytesFilter which passes the bytes through text/template.
func NewTemplateFileFilter() BytesFilter {
t := template.New("config.template").Funcs(templates.FuncMap())
log := logging.Logger()
return func(in []byte) (out []byte, err error) {
if t, err = t.Parse(string(in)); err != nil {
return nil, err
}
buf := &bytes.Buffer{}
if err = t.Execute(buf, nil); err != nil {
return nil, err
}
out = buf.Bytes()
if log.Level >= logrus.TraceLevel {
log.
WithField("content", base64.RawStdEncoding.EncodeToString(out)).
Trace("Templated File Filter completed successfully")
}
return out, nil
}
}