docker-volume-backup/cmd/backup/config_provider.go
pixxon 1d45062100 Move cron scheduling inside application (#338)
* Move cron scheduling inside application

* Make envvar a fallback and check for errors

* Panic significantly less

* propagate error out of runBackup

* Add structured logging

* FIx error propagation to exit

* Enable the new scheduler by default

* Review fixes

* Added docs and better error propagation
2024-02-12 16:04:12 +01:00

82 lines
1.9 KiB
Go

// Copyright 2021-2022 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package main
import (
"fmt"
"os"
"path/filepath"
"github.com/joho/godotenv"
"github.com/offen/envconfig"
)
// envProxy is a function that mimics os.LookupEnv but can read values from any other source
type envProxy func(string) (string, bool)
func loadConfig(lookup envProxy) (*Config, error) {
envconfig.Lookup = func(key string) (string, bool) {
value, okValue := lookup(key)
location, okFile := lookup(key + "_FILE")
switch {
case okValue && !okFile: // only value
return value, true
case !okValue && okFile: // only file
contents, err := os.ReadFile(location)
if err != nil {
return "", false
}
return string(contents), true
case okValue && okFile: // both
return "", false
default: // neither, ignore
return "", false
}
}
var c = &Config{}
if err := envconfig.Process("", c); err != nil {
return nil, fmt.Errorf("failed to process configuration values, error: %w", err)
}
return c, nil
}
func loadEnvVars() (*Config, error) {
return loadConfig(os.LookupEnv)
}
func loadEnvFiles(directory string) ([]*Config, error) {
items, err := os.ReadDir(directory)
if err != nil {
if os.IsNotExist(err) {
return nil, err
}
return nil, fmt.Errorf("failed to read files from env directory, error: %w", err)
}
var cs = make([]*Config, 0)
for _, item := range items {
if !item.IsDir() {
p := filepath.Join(directory, item.Name())
envFile, err := godotenv.Read(p)
if err != nil {
return nil, fmt.Errorf("error reading config file %s, error: %w", p, err)
}
lookup := func(key string) (string, bool) {
val, ok := envFile[key]
return val, ok
}
c, err := loadConfig(lookup)
if err != nil {
return nil, fmt.Errorf("error loading config from file %s, error: %w", p, err)
}
cs = append(cs, c)
}
}
return cs, nil
}