| 1 | package provider |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "io" |
| 7 | "net/http/httptrace" |
| 8 | "sync/atomic" |
| 9 | ) |
| 10 | |
| 11 | // connectionProbe records what the transport did with one request attempt: |
| 12 | // whether it went out on a pooled connection that had been idle, and whether |
| 13 | // any response byte came back on it. |
| 14 | type connectionProbe struct { |
| 15 | idleReuse atomic.Bool |
| 16 | responded atomic.Bool |
| 17 | } |
| 18 | |
| 19 | func (p *connectionProbe) attach(ctx context.Context) context.Context { |
| 20 | return httptrace.WithClientTrace(ctx, &httptrace.ClientTrace{ |
| 21 | GotConn: func(info httptrace.GotConnInfo) { |
| 22 | p.idleReuse.Store(info.Reused && info.WasIdle) |
| 23 | }, |
| 24 | GotFirstResponseByte: func() { p.responded.Store(true) }, |
| 25 | }) |
| 26 | } |
| 27 | |
| 28 | // staleIdleConnection reports whether err is a pooled idle connection that the |
| 29 | // peer or an intermediary had already dropped: it closed before answering |
| 30 | // anything. The request may still have been delivered, so the caller resends |
| 31 | // at most once. |
| 32 | func (p *connectionProbe) staleIdleConnection(ctx context.Context, err error) bool { |
| 33 | if err == nil || ctx.Err() != nil || !p.idleReuse.Load() || p.responded.Load() { |
| 34 | return false |
| 35 | } |
| 36 | if errors.Is(err, io.ErrUnexpectedEOF) || errors.Is(err, io.EOF) { |
| 37 | return true |
| 38 | } |
| 39 | for _, closed := range closedConnectionErrnos { |
| 40 | if errors.Is(err, closed) { |
| 41 | return true |
| 42 | } |
| 43 | } |
| 44 | return false |
| 45 | } |
| 46 |