git.giacomolli.uk - onechat/blob - config.go

   1 package main
   2
   3 import (
   4         "bytes"
   5         "encoding/json"
   6         "errors"
   7         "fmt"
   8         "io"
   9         "os"
  10         "path/filepath"
  11 )
  12
  13 const (
  14         // configEndpointChatGPT names the ChatGPT backend with the subscription
  15         // login.
  16         configEndpointChatGPT = "chatgpt"
  17
  18         // configEndpointAPI names the OpenAI API with an API key.
  19         configEndpointAPI = "api"
  20 )
  21
  22 // loadConfig reads config.json in dir over the defaults. A missing file gives
  23 // the defaults. An unknown field is an error, so a typo does not become a
  24 // silent default.
  25 func loadConfig(dir string) (Config, error) {
  26         config := defaultConfig()
  27         data, err := os.ReadFile(filepath.Join(dir, "config.json"))
  28         if errors.Is(err, os.ErrNotExist) {
  29                 return config, nil
  30         }
  31
  32         if err != nil {
  33                 return Config{}, fmt.Errorf("read config: %w", err)
  34         }
  35
  36         decoder := json.NewDecoder(bytes.NewReader(data))
  37         decoder.DisallowUnknownFields()
  38         err = decoder.Decode(&config)
  39         if err == nil && !errors.Is(decoder.Decode(&struct{}{}), io.EOF) {
  40                 err = errors.New("data after the JSON object")
  41         }
  42
  43         if err == nil {
  44                 err = config.validate()
  45         }
  46
  47         if err != nil {
  48                 return Config{}, fmt.Errorf("config.json: %w", err)
  49         }
  50
  51         return config, nil
  52 }
  53
  54 // Config holds the settings of config.json in the data directory.
  55 type Config struct {
  56         Endpoint  string      `json:"endpoint"`
  57         Compactor ModelConfig `json:"compactor"`
  58 }
  59
  60 // validate makes sure that each setting has a valid value.
  61 func (c Config) validate() error {
  62         if c.Endpoint != configEndpointChatGPT && c.Endpoint != configEndpointAPI {
  63                 return fmt.Errorf("endpoint %q is not %q or %q", c.Endpoint, configEndpointChatGPT, configEndpointAPI)
  64         }
  65
  66         if c.Compactor.Model == "" || c.Compactor.Effort == "" {
  67                 return errors.New("compactor needs a model and an effort")
  68         }
  69
  70         return nil
  71 }
  72
  73 // ModelConfig names a model and its reasoning effort.
  74 type ModelConfig struct {
  75         Model  string `json:"model"`
  76         Effort string `json:"effort"`
  77 }
  78
  79 // defaultConfig returns the settings that apply when config.json does not
  80 // set them.
  81 func defaultConfig() Config {
  82         return Config{
  83                 Endpoint: configEndpointChatGPT,
  84                 Compactor: ModelConfig{
  85                         Model:  "gpt-6.1-sol",
  86                         Effort: "high",
  87                 },
  88         }
  89 }