Merge pull request moby#5407 from tonistiigi/llb-http-user-agent

llb: use buildkit user-agent for HTTP source

Author: crazy-max

frontend/dockerfile/dockerfile_test.go

@@ -2757,6 +2757,11 @@ ADD %s /dest/
 	require.NoError(t, err)
 	require.Equal(t, []byte("content1"), dt)
 
+	// run again to test HEAD request
+	cmd = sb.Cmd(args)
+	err = cmd.Run()
+	require.NoError(t, err)
+
 	// test the default properties
 	dockerfile = []byte(fmt.Sprintf(`
 FROM scratch
@@ -2785,6 +2790,13 @@ ADD %s /dest/
 	fi, err := os.Stat(destFile)
 	require.NoError(t, err)
 	require.Equal(t, modTime.Format(http.TimeFormat), fi.ModTime().Format(http.TimeFormat))
+
+	stats := server.Stats("/foo")
+	require.Len(t, stats.Requests, 2)
+	require.Equal(t, "GET", stats.Requests[0].Method)
+	require.Contains(t, stats.Requests[0].Header.Get("User-Agent"), "buildkit/v")
+	require.Equal(t, "HEAD", stats.Requests[1].Method)
+	require.Contains(t, stats.Requests[1].Header.Get("User-Agent"), "buildkit/v")
 }
 
 func testDockerfileAddArchive(t *testing.T, sb integration.Sandbox) {

source/http/source.go

@@ -26,6 +26,7 @@ import (
 	srctypes "github.com/moby/buildkit/source/types"
 	"github.com/moby/buildkit/util/bklog"
 	"github.com/moby/buildkit/util/tracing"
+	"github.com/moby/buildkit/version"
 	digest "github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
 )
@@ -181,6 +182,7 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, g session.Group, inde
 		return "", "", nil, false, err
 	}
 	req = req.WithContext(ctx)
+	req.Header.Add("User-Agent", version.UserAgent())
 	m := map[string]cacheRefMetadata{}
 
 	// If we request a single ETag in 'If-None-Match', some servers omit the