| 1 | // Package stats records per-call token usage as append-only daily JSONL files |
| 2 | // under the user state root (config.StatsDir), and aggregates them for the |
| 3 | // desktop "usage statistics" panel. |
| 4 | // |
| 5 | // Design notes: |
| 6 | // - Only provider usage (including request-only failures) and turn |
| 7 | // completions (event.TurnDone) are recorded here. Turn markers power the |
| 8 | // panel's "completed turns" metric; |
| 9 | // they are deliberately not presented as distinct conversation sessions. |
| 10 | // Token usage was never persisted before this feature, so token numbers |
| 11 | // accumulate from the day the feature ships. |
| 12 | // - Files are append-only: each record is one JSON line appended with |
| 13 | // O_APPEND. A crash mid-line leaves at most one torn trailing line, which |
| 14 | // decodeRecords tolerates and skips. |
| 15 | package stats |
| 16 | |
| 17 | import ( |
| 18 | "bufio" |
| 19 | "context" |
| 20 | "encoding/json" |
| 21 | "errors" |
| 22 | "io" |
| 23 | "os" |
| 24 | "path/filepath" |
| 25 | "strings" |
| 26 | "time" |
| 27 | |
| 28 | "reasonix/internal/filelock" |
| 29 | ) |
| 30 | |
| 31 | // dayLayout names one stats file per UTC-free local day, e.g. 2026-08-02.jsonl. |
| 32 | const dayLayout = "2006-01-02" |
| 33 | |
| 34 | const appendLockTimeout = 2 * time.Second |
| 35 | |
| 36 | // record is one line in a daily stats file. TurnDone marks a completed turn so |
| 37 | // per-day turn counts are available without touching session files. |
| 38 | type record struct { |
| 39 | Timestamp time.Time `json:"ts"` |
| 40 | ModelRef string `json:"model,omitempty"` // canonical "provider/model" |
| 41 | Source string `json:"source,omitempty"` // desktop | cli | serve | bot | remote |
| 42 | Prompt int `json:"prompt,omitempty"` |
| 43 | Completion int `json:"completion,omitempty"` |
| 44 | Reasoning int `json:"reasoning,omitempty"` |
| 45 | CacheHit int `json:"cache_hit,omitempty"` |
| 46 | CacheMiss int `json:"cache_miss,omitempty"` |
| 47 | Total int `json:"total,omitempty"` |
| 48 | Requests int `json:"requests,omitempty"` // provider requests represented by this row |
| 49 | Turn bool `json:"turn,omitempty"` // true for TurnDone marker rows |
| 50 | } |
| 51 | |
| 52 | // Writer appends records to the daily stats file for a given stats dir. |
| 53 | type Writer struct { |
| 54 | dir string |
| 55 | } |
| 56 | |
| 57 | // NewWriter returns a Writer rooted at dir. An empty dir disables recording |
| 58 | // (query-only usage). |
| 59 | func NewWriter(dir string) *Writer { |
| 60 | return &Writer{dir: strings.TrimSpace(dir)} |
| 61 | } |
| 62 | |
| 63 | // Append writes one record, appending to the daily file (O_APPEND) so records |
| 64 | // from concurrent turns never overwrite each other. Each record is a single |
| 65 | // JSON line; a crash mid-line leaves at most one torn trailing line, which |
| 66 | // decodeRecords tolerates. |
| 67 | func (w *Writer) Append(r record) error { |
| 68 | if w == nil || w.dir == "" { |
| 69 | return nil |
| 70 | } |
| 71 | day := r.Timestamp.Format(dayLayout) |
| 72 | path := filepath.Join(w.dir, day+".jsonl") |
| 73 | b, err := json.Marshal(r) |
| 74 | if err != nil { |
| 75 | return err |
| 76 | } |
| 77 | if err := os.MkdirAll(w.dir, 0o700); err != nil { |
| 78 | return err |
| 79 | } |
| 80 | ctx, cancel := context.WithTimeout(context.Background(), appendLockTimeout) |
| 81 | defer cancel() |
| 82 | release, err := filelock.Acquire(ctx, filepath.Join(w.dir, ".append.lock")) |
| 83 | if err != nil { |
| 84 | return err |
| 85 | } |
| 86 | defer release() |
| 87 | f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0o600) |
| 88 | if err != nil { |
| 89 | return err |
| 90 | } |
| 91 | defer f.Close() |
| 92 | if err := ensureRecordBoundary(f); err != nil { |
| 93 | return err |
| 94 | } |
| 95 | _, err = f.Write(append(b, '\n')) |
| 96 | return err |
| 97 | } |
| 98 | |
| 99 | // ensureRecordBoundary separates a torn trailing JSON object from the next |
| 100 | // append. The caller holds the cross-process append lock, so checking the last |
| 101 | // byte and repairing it cannot race another Reasonix writer. |
| 102 | func ensureRecordBoundary(f *os.File) error { |
| 103 | st, err := f.Stat() |
| 104 | if err != nil || st.Size() == 0 { |
| 105 | return err |
| 106 | } |
| 107 | var tail [1]byte |
| 108 | if _, err := f.ReadAt(tail[:], st.Size()-1); err != nil { |
| 109 | return err |
| 110 | } |
| 111 | if tail[0] == '\n' { |
| 112 | return nil |
| 113 | } |
| 114 | _, err = f.Write([]byte{'\n'}) |
| 115 | return err |
| 116 | } |
| 117 | |
| 118 | // readDaily loads one daily file into records. Missing files yield nil, nil. |
| 119 | func readDaily(dir, day string) ([]record, error) { |
| 120 | if strings.TrimSpace(dir) == "" { |
| 121 | return nil, nil |
| 122 | } |
| 123 | f, err := os.Open(filepath.Join(dir, day+".jsonl")) |
| 124 | if errors.Is(err, os.ErrNotExist) { |
| 125 | return nil, nil |
| 126 | } |
| 127 | if err != nil { |
| 128 | return nil, err |
| 129 | } |
| 130 | defer f.Close() |
| 131 | return decodeRecords(f) |
| 132 | } |
| 133 | |
| 134 | // readDailyRange snapshots the available daily files with one directory scan, |
| 135 | // then reads only dates requested by the query. Long custom ranges are often |
| 136 | // mostly empty; avoiding one failed os.Open per absent day keeps their cost |
| 137 | // proportional to the data that actually exists. |
| 138 | func readDailyRange(dir string, days []string) (map[string][]record, error) { |
| 139 | out := make(map[string][]record) |
| 140 | if strings.TrimSpace(dir) == "" || len(days) == 0 { |
| 141 | return out, nil |
| 142 | } |
| 143 | wanted := make(map[string]struct{}, len(days)) |
| 144 | for _, day := range days { |
| 145 | wanted[day] = struct{}{} |
| 146 | } |
| 147 | entries, err := os.ReadDir(dir) |
| 148 | if errors.Is(err, os.ErrNotExist) { |
| 149 | return out, nil |
| 150 | } |
| 151 | if err != nil { |
| 152 | return nil, err |
| 153 | } |
| 154 | for _, entry := range entries { |
| 155 | if entry.IsDir() { |
| 156 | continue |
| 157 | } |
| 158 | name := entry.Name() |
| 159 | if !strings.HasSuffix(name, ".jsonl") { |
| 160 | continue |
| 161 | } |
| 162 | day := strings.TrimSuffix(name, ".jsonl") |
| 163 | if _, ok := wanted[day]; !ok { |
| 164 | continue |
| 165 | } |
| 166 | records, err := readDaily(dir, day) |
| 167 | if err != nil { |
| 168 | return nil, err |
| 169 | } |
| 170 | out[day] = records |
| 171 | } |
| 172 | return out, nil |
| 173 | } |
| 174 | |
| 175 | func decodeRecords(r io.Reader) ([]record, error) { |
| 176 | var out []record |
| 177 | sc := bufio.NewScanner(r) |
| 178 | sc.Buffer(make([]byte, 0, 64*1024), 1024*1024) |
| 179 | for sc.Scan() { |
| 180 | line := strings.TrimSpace(sc.Text()) |
| 181 | if line == "" { |
| 182 | continue |
| 183 | } |
| 184 | var rec record |
| 185 | if err := json.Unmarshal([]byte(line), &rec); err != nil { |
| 186 | // Malformed lines (a crash mid-write or a manual edit) are skipped |
| 187 | // rather than failing the whole day's aggregation. This tolerates |
| 188 | // any number of bad lines; a fully corrupt file reads as an empty |
| 189 | // day, which is preferable to the panel erroring out. |
| 190 | continue |
| 191 | } |
| 192 | out = append(out, rec) |
| 193 | } |
| 194 | return out, sc.Err() |
| 195 | } |
| 196 | |
| 197 | // daysInRange lists the daily file names (without extension) whose timestamps |
| 198 | // intersect [from, to], inclusive. |
| 199 | func daysInRange(from, to time.Time) []string { |
| 200 | from = dayStart(from) |
| 201 | to = dayStart(to) |
| 202 | if to.Before(from) { |
| 203 | return nil |
| 204 | } |
| 205 | var days []string |
| 206 | for d := from; !d.After(to); d = d.AddDate(0, 0, 1) { |
| 207 | days = append(days, d.Format(dayLayout)) |
| 208 | } |
| 209 | return days |
| 210 | } |
| 211 | |
| 212 | func dayStart(t time.Time) time.Time { |
| 213 | y, m, d := t.Date() |
| 214 | return time.Date(y, m, d, 0, 0, 0, 0, t.Location()) |
| 215 | } |
| 216 |