| 1 | package usage |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "os" |
| 9 | "time" |
| 10 | |
| 11 | "github.com/carlosframework/platform/internal/release" |
| 12 | ) |
| 13 | |
| 14 | // ScanRow is one account's on-demand scanning work for a UTC day. |
| 15 | type ScanRow struct { |
| 16 | Objects int64 `json:"objects"` |
| 17 | Bytes int64 `json:"bytes"` |
| 18 | } |
| 19 | |
| 20 | // ScanDay is usage/scan/<date>.json, keyed by account. |
| 21 | type ScanDay struct { |
| 22 | V int `json:"v"` // 1 |
| 23 | Date string `json:"date"` |
| 24 | Accounts map[string]ScanRow `json:"accounts"` |
| 25 | } |
| 26 | |
| 27 | func ScanDayKey(date string) string { return "usage/scan/" + date + ".json" } |
| 28 | |
| 29 | const ScanPrefix = "usage/scan/" |
| 30 | |
| 31 | func (d *ScanDay) AddDeltas(deltas map[string]ScanRow) { |
| 32 | if d.Accounts == nil { |
| 33 | d.Accounts = map[string]ScanRow{} |
| 34 | } |
| 35 | for account, delta := range deltas { |
| 36 | row := d.Accounts[account] |
| 37 | row.Objects += delta.Objects |
| 38 | row.Bytes += delta.Bytes |
| 39 | d.Accounts[account] = row |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | // UpsertScanDay folds one drain tick into its UTC day. Empty ticks write |
| 44 | // nothing; a compare-and-swap loss re-reads before adding so concurrent |
| 45 | // consoles cannot silently replace each other's counts. |
| 46 | func UpsertScanDay(ctx context.Context, s release.Store, now time.Time, deltas map[string]ScanRow) error { |
| 47 | if len(deltas) == 0 { |
| 48 | return nil |
| 49 | } |
| 50 | date := DayOf(now) |
| 51 | key := ScanDayKey(date) |
| 52 | for attempt := 0; attempt < 3; attempt++ { |
| 53 | day := ScanDay{V: 1, Date: date} |
| 54 | raw, etag, err := s.Get(ctx, key) |
| 55 | switch { |
| 56 | case err == nil: |
| 57 | if err := json.Unmarshal(raw, &day); err != nil { |
| 58 | return fmt.Errorf("usage: parse %s: %w", key, err) |
| 59 | } |
| 60 | case errors.Is(err, os.ErrNotExist): |
| 61 | etag = "" |
| 62 | default: |
| 63 | return err |
| 64 | } |
| 65 | day.AddDeltas(deltas) |
| 66 | out, err := json.Marshal(day) |
| 67 | if err != nil { |
| 68 | return err |
| 69 | } |
| 70 | if _, err := s.Put(ctx, key, out, etag); err == nil { |
| 71 | return nil |
| 72 | } else if !errors.Is(err, release.ErrCASConflict) { |
| 73 | return err |
| 74 | } |
| 75 | } |
| 76 | return fmt.Errorf("usage: %s: lost CAS race three times", key) |
| 77 | } |
| 78 | |
amadan