feat(agent): relax provider http timeouts (#348)

internal/models/http_client.go

@@ -0,0 +1,39 @@
+package models
+
+import (
+	"net/http"
+	"time"
+)
+
+const (
+	DefaultProviderRequestTimeout      = 2 * time.Minute
+	DefaultProviderProbeTimeout        = 60 * time.Second
+	DefaultProviderTLSHandshakeTimeout = 30 * time.Second
+)
+
+var defaultProviderTransport = newDefaultProviderTransport()
+
+// NewProviderHTTPClient returns an HTTP client for model/provider traffic.
+// When timeout is zero or negative, the caller is expected to enforce limits
+// via context deadlines, which keeps streaming responses unbounded by the
+// client's global timeout while still using the relaxed TLS handshake window.
+func NewProviderHTTPClient(timeout time.Duration) *http.Client {
+	client := &http.Client{Transport: defaultProviderTransport}
+	if timeout > 0 {
+		client.Timeout = timeout
+	}
+	return client
+}
+
+func newDefaultProviderTransport() *http.Transport {
+	base, ok := http.DefaultTransport.(*http.Transport)
+	if !ok {
+		return &http.Transport{TLSHandshakeTimeout: DefaultProviderTLSHandshakeTimeout}
+	}
+
+	transport := base.Clone()
+	if transport.TLSHandshakeTimeout < DefaultProviderTLSHandshakeTimeout {
+		transport.TLSHandshakeTimeout = DefaultProviderTLSHandshakeTimeout
+	}
+	return transport
+}