1package fantasy
2
3import (
4 "errors"
5 "fmt"
6 "io"
7 "net/http"
8 "strconv"
9 "strings"
10
11 "github.com/charmbracelet/x/exp/slice"
12)
13
14// Error is a custom error type for the fantasy package.
15type Error struct {
16 Message string
17 Title string
18 Cause error
19}
20
21func (err *Error) Error() string {
22 if err.Title == "" {
23 return err.Message
24 }
25 return fmt.Sprintf("%s: %s", err.Title, err.Message)
26}
27
28func (err Error) Unwrap() error {
29 return err.Cause
30}
31
32// ProviderError represents an error returned by an external provider.
33type ProviderError struct {
34 Message string
35 Title string
36 Cause error
37
38 URL string
39 StatusCode int
40 RequestBody []byte
41 ResponseHeaders map[string]string
42 ResponseBody []byte
43
44 ContextUsedTokens int
45 ContextMaxTokens int
46 ContextTooLargeErr bool
47}
48
49func (m *ProviderError) Error() string {
50 if m.Title == "" {
51 return m.Message
52 }
53 return fmt.Sprintf("%s: %s", m.Title, m.Message)
54}
55
56// IsRetryable reports whether the error should be retried.
57// It returns true if the underlying cause is io.ErrUnexpectedEOF, if the
58// "x-should-retry" response header evaluates to true, or if the HTTP status
59// code indicates a retryable condition (408, 409, 429, or any 5xx).
60func (m *ProviderError) IsRetryable() bool {
61 // We're mostly mimicking OpenAI's Go SDK here:
62 // https://github.com/openai/openai-go/blob/b9d280a37149430982e9dfeed16c41d27d45cfc5/internal/requestconfig/requestconfig.go#L244
63 if errors.Is(m.Cause, io.ErrUnexpectedEOF) {
64 return true
65 }
66 if m.shouldRetryHeader() {
67 return true
68 }
69 return m.StatusCode == http.StatusRequestTimeout ||
70 m.StatusCode == http.StatusConflict ||
71 m.StatusCode == http.StatusTooManyRequests ||
72 m.StatusCode >= http.StatusInternalServerError
73}
74
75func (m *ProviderError) shouldRetryHeader() bool {
76 if m.ResponseHeaders == nil {
77 return false
78 }
79 for k, v := range m.ResponseHeaders {
80 if strings.EqualFold(k, "x-should-retry") {
81 b, _ := strconv.ParseBool(v)
82 return b
83 }
84 }
85 return false
86}
87
88// IsContextTooLarge checks if the error is due to the context exceeding the model's limit.
89func (m *ProviderError) IsContextTooLarge() bool {
90 return m.ContextTooLargeErr || m.ContextMaxTokens > 0 || m.ContextUsedTokens > 0
91}
92
93// RetryError represents an error that occurred during retry operations.
94type RetryError struct {
95 Errors []error
96}
97
98func (e *RetryError) Error() string {
99 if err, ok := slice.Last(e.Errors); ok {
100 return fmt.Sprintf("retry error: %v", err)
101 }
102 return "retry error: no underlying errors"
103}
104
105func (e RetryError) Unwrap() error {
106 if err, ok := slice.Last(e.Errors); ok {
107 return err
108 }
109 return nil
110}
111
112// ErrorTitleForStatusCode returns a human-readable title for a given HTTP status code.
113func ErrorTitleForStatusCode(statusCode int) string {
114 return strings.ToLower(http.StatusText(statusCode))
115}
116
117// NoObjectGeneratedError is returned when object generation fails
118// due to parsing errors, validation errors, or model failures.
119type NoObjectGeneratedError struct {
120 RawText string
121 ParseError error
122 ValidationError error
123 Usage Usage
124 FinishReason FinishReason
125}
126
127// Error implements the error interface.
128func (e *NoObjectGeneratedError) Error() string {
129 if e.ValidationError != nil {
130 return fmt.Sprintf("object validation failed: %v", e.ValidationError)
131 }
132 if e.ParseError != nil {
133 return fmt.Sprintf("failed to parse object: %v", e.ParseError)
134 }
135 return "failed to generate object"
136}
137
138// IsNoObjectGeneratedError checks if an error is of type NoObjectGeneratedError.
139func IsNoObjectGeneratedError(err error) bool {
140 var target *NoObjectGeneratedError
141 return errors.As(err, &target)
142}