f95d96acd8
It exists a default configuration. It can be overwritten by adding a configuration.yaml. This can again be overwritten by environment variables.
117 lines
2.3 KiB
Go
117 lines
2.3 KiB
Go
package config
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import (
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"flag"
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"fmt"
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"gopkg.in/yaml.v3"
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"log"
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"os"
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"reflect"
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"strconv"
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"strings"
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)
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var (
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Config = &configuration{
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Server: server{
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Address: "127.0.0.1",
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Port: 3000,
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},
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Nomad: nomad{
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Address: "",
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Token: "",
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TLS: false,
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},
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Logger: logger{
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Level: "INFO",
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},
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}
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)
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type server struct {
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Address string
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Port int
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}
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type nomad struct {
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Address string
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Token string
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TLS bool
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}
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type logger struct {
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Level string
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}
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type configuration struct {
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Server server
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Nomad nomad
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Logger logger
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}
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func InitConfig() {
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content := readConfigFile()
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Config.mergeYaml(content)
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Config.mergeEnvironmentVariables()
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}
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func readConfigFile() []byte {
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var configFilePath string
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flag.StringVar(&configFilePath, "config", "./configuration.yaml", "path of the yaml config file")
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data, err := os.ReadFile(configFilePath)
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if err != nil {
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log.Printf("Using default configuration... (%v)", err)
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}
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return data
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}
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func (c *configuration) mergeYaml(content []byte) {
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if err := yaml.Unmarshal(content, c); err != nil {
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log.Fatalf("Could not parse configuration: %v", err)
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}
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}
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func (c *configuration) mergeEnvironmentVariables() {
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readFromEnvironment("POSEIDON", reflect.ValueOf(c).Elem())
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}
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func readFromEnvironment(prefix string, value reflect.Value) {
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if !value.CanSet() || !value.CanInterface() {
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return
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}
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if value.Kind() != reflect.Struct {
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content, ok := os.LookupEnv(prefix)
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if !ok {
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return
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}
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switch value.Kind() {
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case reflect.String:
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value.SetString(content)
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case reflect.Int:
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integer, err := strconv.Atoi(content)
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if err != nil {
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log.Printf("Could not parse environment variable %s with value '%q' as integer", prefix, content)
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return
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}
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value.SetInt(int64(integer))
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case reflect.Bool:
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boolean, err := strconv.ParseBool(content)
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if err != nil {
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log.Printf("Could not parse environment variable %s with value '%q' as boolean", prefix, content)
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return
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}
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value.SetBool(boolean)
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default:
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// ignore this field
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log.Printf("Setting configuration options of type %s via environment variables is not supported", value.Type().Name())
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}
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} else {
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for i := 0; i < value.NumField(); i++ {
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fieldName := value.Type().Field(i).Name
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newPrefix := fmt.Sprintf("%s_%s", prefix, strings.ToUpper(fieldName))
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readFromEnvironment(newPrefix, value.Field(i))
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}
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}
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}
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