feat(http): Add connection timeout

http/connect.go

@@ -0,0 +1,38 @@
+package http
+
+import (
+	"context"
+	"fmt"
+	"net"
+	stdhttp "net/http"
+	"time"
+)
+
+// ConnectTimeout limits the time spent establishing a network connection.
+func (c *Client) ConnectTimeout(timeout time.Duration) (*Client, error) {
+	if timeout <= 0 {
+		return nil, fmt.Errorf("connect timeout must be greater than zero, got %s", timeout)
+	}
+
+	base := c.httpClient.Transport
+	if base == nil {
+		base = stdhttp.DefaultTransport
+	}
+	transport, ok := base.(*stdhttp.Transport)
+	if !ok {
+		return nil, fmt.Errorf("configure connect timeout: transport %T is not an *http.Transport", base)
+	}
+
+	configured := transport.Clone()
+	dialContext := configured.DialContext
+	if dialContext == nil {
+		dialContext = (&net.Dialer{}).DialContext
+	}
+	configured.DialContext = func(ctx context.Context, network, address string) (net.Conn, error) {
+		connectCtx, cancel := context.WithTimeout(ctx, timeout)
+		defer cancel()
+		return dialContext(connectCtx, network, address)
+	}
+	c.httpClient.Transport = configured
+	return c, nil
+}

http/connect_test.go

@@ -0,0 +1,78 @@
+package http
+
+import (
+	"context"
+	"errors"
+	"net"
+	stdhttp "net/http"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestConnectTimeout(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "HTTP Connect Timeout Suite")
+}
+
+var _ = Describe("Client connect timeout", func() {
+	It("rejects non-positive durations", func() {
+		for _, timeout := range []time.Duration{0, -time.Nanosecond} {
+			_, err := NewClient().ConnectTimeout(timeout)
+			Expect(err).To(MatchError(ContainSubstring("connect timeout must be greater than zero")), timeout)
+		}
+	})
+
+	It("bounds the configured dialer and preserves client settings", func() {
+		var dialAttempts atomic.Int32
+		originalTransport := &stdhttp.Transport{
+			DisableKeepAlives: true,
+			MaxIdleConns:      17,
+			DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+				dialAttempts.Add(1)
+				<-ctx.Done()
+				return nil, ctx.Err()
+			},
+		}
+		client := NewClient().Timeout(time.Second)
+		client.httpClient.Transport = originalTransport
+
+		configured, err := client.ConnectTimeout(25 * time.Millisecond)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(configured).To(BeIdenticalTo(client))
+		transport := client.httpClient.Transport.(*stdhttp.Transport)
+		Expect(transport).ToNot(BeIdenticalTo(originalTransport))
+		Expect(transport.DisableKeepAlives).To(BeTrue())
+		Expect(transport.MaxIdleConns).To(Equal(17))
+		Expect(client.httpClient.Timeout).To(Equal(time.Second))
+
+		started := time.Now()
+		_, err = client.httpClient.Get("http://example.test")
+		Expect(errors.Is(err, context.DeadlineExceeded)).To(BeTrue())
+		Expect(time.Since(started)).To(BeNumerically(">=", 25*time.Millisecond))
+		Expect(time.Since(started)).To(BeNumerically("<", time.Second))
+		Expect(dialAttempts.Load()).To(Equal(int32(1)))
+	})
+
+	It("honors an earlier request deadline", func() {
+		client := NewClient()
+		client.httpClient.Transport = &stdhttp.Transport{DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+			<-ctx.Done()
+			return nil, ctx.Err()
+		}}
+		_, err := client.ConnectTimeout(time.Second)
+		Expect(err).ToNot(HaveOccurred())
+
+		ctx, cancel := context.WithTimeout(context.Background(), 25*time.Millisecond)
+		defer cancel()
+		request, err := stdhttp.NewRequestWithContext(ctx, stdhttp.MethodGet, "http://example.test", nil)
+		Expect(err).ToNot(HaveOccurred())
+		started := time.Now()
+		_, err = client.httpClient.Do(request)
+		Expect(errors.Is(err, context.DeadlineExceeded)).To(BeTrue())
+		Expect(time.Since(started)).To(BeNumerically("<", time.Second))
+	})
+})