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
  39         err = decoder.Decode(&config)
  40         if err == nil && !errors.Is(decoder.Decode(&struct{}{}), io.EOF) {
  41                 err = errors.New("data after the JSON object")
  42         }
  43
  44         if err == nil {
  45                 err = config.validate()
  46         }
  47
  48         if err != nil {
  49                 return Config{}, fmt.Errorf("config.json: %w", err)
  50         }
  51
  52         return config, nil
  53 }
  54
  55 // Config holds the settings of config.json in the data directory.
  56 type Config struct {
  57         Endpoint  string      `json:"endpoint"`
  58         Compactor ModelConfig `json:"compactor"`
  59 }
  60
  61 // validate makes sure that each setting has a valid value.
  62 func (c Config) validate() error {
  63         if c.Endpoint != configEndpointChatGPT && c.Endpoint != configEndpointAPI {
  64                 return fmt.Errorf("endpoint %q is not %q or %q", c.Endpoint, configEndpointChatGPT, configEndpointAPI)
  65         }
  66
  67         if c.Compactor.Model == "" || c.Compactor.Effort == "" {
  68                 return errors.New("compactor needs a model and an effort")
  69         }
  70
  71         return nil
  72 }
  73
  74 // ModelConfig names a model and its reasoning effort.
  75 type ModelConfig struct {
  76         Model  string `json:"model"`
  77         Effort string `json:"effort"`
  78 }
  79
  80 // defaultConfig returns the settings that apply when config.json does not
  81 // set them.
  82 func defaultConfig() Config {
  83         return Config{
  84                 Endpoint: configEndpointChatGPT,
  85                 Compactor: ModelConfig{
  86                         Model:  "gpt-6.1-sol",
  87                         Effort: "high",
  88                 },
  89         }
  90 }