Update dependencies

vendor/github.com/aws/smithy-go/transport/http/metrics.go

@@ -0,0 +1,198 @@
+package http
+
+import (
+	"context"
+	"crypto/tls"
+	"net/http"
+	"net/http/httptrace"
+	"sync/atomic"
+	"time"
+
+	"github.com/aws/smithy-go/metrics"
+)
+
+var now = time.Now
+
+// withMetrics instruments an HTTP client and context to collect HTTP metrics.
+func withMetrics(parent context.Context, client ClientDo, meter metrics.Meter) (
+	context.Context, ClientDo, error,
+) {
+	hm, err := newHTTPMetrics(meter)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	ctx := httptrace.WithClientTrace(parent, &httptrace.ClientTrace{
+		DNSStart:          hm.DNSStart,
+		ConnectStart:      hm.ConnectStart,
+		TLSHandshakeStart: hm.TLSHandshakeStart,
+
+		GotConn:              hm.GotConn(parent),
+		PutIdleConn:          hm.PutIdleConn(parent),
+		ConnectDone:          hm.ConnectDone(parent),
+		DNSDone:              hm.DNSDone(parent),
+		TLSHandshakeDone:     hm.TLSHandshakeDone(parent),
+		GotFirstResponseByte: hm.GotFirstResponseByte(parent),
+	})
+	return ctx, &timedClientDo{client, hm}, nil
+}
+
+type timedClientDo struct {
+	ClientDo
+	hm *httpMetrics
+}
+
+func (c *timedClientDo) Do(r *http.Request) (*http.Response, error) {
+	c.hm.doStart.Store(now())
+	resp, err := c.ClientDo.Do(r)
+
+	c.hm.DoRequestDuration.Record(r.Context(), c.hm.doStart.Elapsed())
+	return resp, err
+}
+
+type httpMetrics struct {
+	DNSLookupDuration    metrics.Float64Histogram   // client.http.connections.dns_lookup_duration
+	ConnectDuration      metrics.Float64Histogram   // client.http.connections.acquire_duration
+	TLSHandshakeDuration metrics.Float64Histogram   // client.http.connections.tls_handshake_duration
+	ConnectionUsage      metrics.Int64UpDownCounter // client.http.connections.usage
+
+	DoRequestDuration metrics.Float64Histogram // client.http.do_request_duration
+	TimeToFirstByte   metrics.Float64Histogram // client.http.time_to_first_byte
+
+	doStart      safeTime
+	dnsStart     safeTime
+	connectStart safeTime
+	tlsStart     safeTime
+}
+
+func newHTTPMetrics(meter metrics.Meter) (*httpMetrics, error) {
+	hm := &httpMetrics{}
+
+	var err error
+	hm.DNSLookupDuration, err = meter.Float64Histogram("client.http.connections.dns_lookup_duration", func(o *metrics.InstrumentOptions) {
+		o.UnitLabel = "s"
+		o.Description = "The time it takes a request to perform DNS lookup."
+	})
+	if err != nil {
+		return nil, err
+	}
+	hm.ConnectDuration, err = meter.Float64Histogram("client.http.connections.acquire_duration", func(o *metrics.InstrumentOptions) {
+		o.UnitLabel = "s"
+		o.Description = "The time it takes a request to acquire a connection."
+	})
+	if err != nil {
+		return nil, err
+	}
+	hm.TLSHandshakeDuration, err = meter.Float64Histogram("client.http.connections.tls_handshake_duration", func(o *metrics.InstrumentOptions) {
+		o.UnitLabel = "s"
+		o.Description = "The time it takes an HTTP request to perform the TLS handshake."
+	})
+	if err != nil {
+		return nil, err
+	}
+	hm.ConnectionUsage, err = meter.Int64UpDownCounter("client.http.connections.usage", func(o *metrics.InstrumentOptions) {
+		o.UnitLabel = "{connection}"
+		o.Description = "Current state of connections pool."
+	})
+	if err != nil {
+		return nil, err
+	}
+	hm.DoRequestDuration, err = meter.Float64Histogram("client.http.do_request_duration", func(o *metrics.InstrumentOptions) {
+		o.UnitLabel = "s"
+		o.Description = "Time spent performing an entire HTTP transaction."
+	})
+	if err != nil {
+		return nil, err
+	}
+	hm.TimeToFirstByte, err = meter.Float64Histogram("client.http.time_to_first_byte", func(o *metrics.InstrumentOptions) {
+		o.UnitLabel = "s"
+		o.Description = "Time from start of transaction to when the first response byte is available."
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return hm, nil
+}
+
+func (m *httpMetrics) DNSStart(httptrace.DNSStartInfo) {
+	m.dnsStart.Store(now())
+}
+
+func (m *httpMetrics) ConnectStart(string, string) {
+	m.connectStart.Store(now())
+}
+
+func (m *httpMetrics) TLSHandshakeStart() {
+	m.tlsStart.Store(now())
+}
+
+func (m *httpMetrics) GotConn(ctx context.Context) func(httptrace.GotConnInfo) {
+	return func(httptrace.GotConnInfo) {
+		m.addConnAcquired(ctx, 1)
+	}
+}
+
+func (m *httpMetrics) PutIdleConn(ctx context.Context) func(error) {
+	return func(error) {
+		m.addConnAcquired(ctx, -1)
+	}
+}
+
+func (m *httpMetrics) DNSDone(ctx context.Context) func(httptrace.DNSDoneInfo) {
+	return func(httptrace.DNSDoneInfo) {
+		m.DNSLookupDuration.Record(ctx, m.dnsStart.Elapsed())
+	}
+}
+
+func (m *httpMetrics) ConnectDone(ctx context.Context) func(string, string, error) {
+	return func(string, string, error) {
+		m.ConnectDuration.Record(ctx, m.connectStart.Elapsed())
+	}
+}
+
+func (m *httpMetrics) TLSHandshakeDone(ctx context.Context) func(tls.ConnectionState, error) {
+	return func(tls.ConnectionState, error) {
+		m.TLSHandshakeDuration.Record(ctx, m.tlsStart.Elapsed())
+	}
+}
+
+func (m *httpMetrics) GotFirstResponseByte(ctx context.Context) func() {
+	return func() {
+		m.TimeToFirstByte.Record(ctx, m.doStart.Elapsed())
+	}
+}
+
+func (m *httpMetrics) addConnAcquired(ctx context.Context, incr int64) {
+	m.ConnectionUsage.Add(ctx, incr, func(o *metrics.RecordMetricOptions) {
+		o.Properties.Set("state", "acquired")
+	})
+}
+
+// Not used: it is recommended to track acquired vs idle conn, but we can't
+// determine when something is truly idle with the current HTTP client hooks
+// available to us.
+func (m *httpMetrics) addConnIdle(ctx context.Context, incr int64) {
+	m.ConnectionUsage.Add(ctx, incr, func(o *metrics.RecordMetricOptions) {
+		o.Properties.Set("state", "idle")
+	})
+}
+
+type safeTime struct {
+	atomic.Value // time.Time
+}
+
+func (st *safeTime) Store(v time.Time) {
+	st.Value.Store(v)
+}
+
+func (st *safeTime) Load() time.Time {
+	t, _ := st.Value.Load().(time.Time)
+	return t
+}
+
+func (st *safeTime) Elapsed() float64 {
+	end := now()
+	elapsed := end.Sub(st.Load())
+	return float64(elapsed) / 1e9
+}