Mark EOF errors coming from http request as downstream (#1192)

* Mark EOF errors comming from http request as downstream

* Fix comment

* Only http io.EOF errors are cosidered downstream

* Update comment

experimental/status/status_source.go

@@ -5,6 +5,7 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"net/http"
 	"net/url"
@@ -142,7 +143,8 @@ func IsDownstreamHTTPError(err error) bool {
 	return IsDownstreamError(err) ||
 		isConnectionResetOrRefusedError(err) ||
 		isDNSNotFoundError(err) ||
-		isTLSCertificateVerificationError(err)
+		isTLSCertificateVerificationError(err) ||
+		isHTTPEOFError(err)
 }
 
 // InCancelledError returns true if err is context.Canceled or is gRPC status Canceled.
@@ -202,6 +204,20 @@ func isTLSCertificateVerificationError(err error) bool {
 	return false
 }
 
+// isHTTPEOFError returns true if the error is an EOF error inside of url.Error or net.OpError, indicating the connection was closed prematurely by server
+func isHTTPEOFError(err error) bool {
+	var netErr *net.OpError
+	if errors.As(err, &netErr) {
+		return errors.Is(netErr.Err, io.EOF)
+	}
+
+	var urlErr *url.Error
+	if errors.As(err, &urlErr) {
+		return errors.Is(urlErr.Err, io.EOF)
+	}
+	return false
+}
+
 type sourceCtxKey struct{}
 
 // SourceFromContext returns the source stored in the context.

experimental/status/status_source_test.go

@@ -5,6 +5,7 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"net/url"
 	"os"
@@ -248,6 +249,36 @@ func TestIsDownstreamHTTPError(t *testing.T) {
 			err:      x509.UnknownAuthorityError{},
 			expected: true,
 		},
+		{
+			name:     "nil error",
+			err:      nil,
+			expected: false,
+		},
+		{
+			name:     "io.EOF error",
+			err:      io.EOF,
+			expected: false,
+		},
+		{
+			name:     "url io.EOF error",
+			err:      &url.Error{Op: "Get", URL: "https://example.com", Err: io.EOF},
+			expected: true,
+		},
+		{
+			name:     "net op io.EOF error",
+			err:      &net.OpError{Err: io.EOF},
+			expected: true,
+		},
+		{
+			name:     "wrapped url io.EOF error",
+			err:      fmt.Errorf("wrapped: %w", &url.Error{Op: "Get", URL: "https://example.com", Err: io.EOF}),
+			expected: true,
+		},
+		{
+			name:     "joined error with io.EOF",
+			err:      errors.Join(io.EOF, &url.Error{Op: "Get", URL: "https://example.com", Err: io.EOF}),
+			expected: true,
+		},
 	}
 	for _, tc := range tcs {
 		t.Run(tc.name, func(t *testing.T) {