Logging: sourcemap support for frontend stacktraces (#30590)

pkg/api/frontendlogging/source_maps.go

@@ -0,0 +1,161 @@
+package frontendlogging
+
+import (
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	sourcemap "github.com/go-sourcemap/sourcemap"
+
+	"github.com/getsentry/sentry-go"
+	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+type sourceMapLocation struct {
+	dir      string
+	path     string
+	pluginID string
+}
+
+type sourceMap struct {
+	consumer *sourcemap.Consumer
+	pluginID string
+}
+
+type ReadSourceMapFn func(dir string, path string) ([]byte, error)
+
+func ReadSourceMapFromFS(dir string, path string) ([]byte, error) {
+	file, err := http.Dir(dir).Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if err := file.Close(); err != nil {
+			logger.Error("Failed to close source map file", "err", err)
+		}
+	}()
+	return ioutil.ReadAll(file)
+}
+
+type SourceMapStore struct {
+	cache         map[string]*sourceMap
+	cfg           *setting.Cfg
+	readSourceMap ReadSourceMapFn
+	sync.Mutex
+}
+
+func NewSourceMapStore(cfg *setting.Cfg, readSourceMap ReadSourceMapFn) *SourceMapStore {
+	return &SourceMapStore{
+		cache:         make(map[string]*sourceMap),
+		cfg:           cfg,
+		readSourceMap: readSourceMap,
+	}
+}
+
+/* guessSourceMapLocation will attempt to guess location of a source map on fs.
+ * it does not read the source file or make any web requests,
+ * just assumes that a [source filename].map file might exist in the same dir as the source file
+ * and only considers sources coming from grafana core or plugins`
+ */
+func (store *SourceMapStore) guessSourceMapLocation(sourceURL string) (*sourceMapLocation, error) {
+	u, err := url.Parse(sourceURL)
+	if err != nil {
+		return nil, err
+	}
+
+	// determine if source comes from grafana core, look in public build dir
+	if strings.HasPrefix(u.Path, "/public/build/") {
+		return &sourceMapLocation{
+			dir:      store.cfg.StaticRootPath,
+			path:     filepath.Join("build", u.Path[len("/public/build/"):]) + ".map",
+			pluginID: "",
+		}, nil
+		// if source comes from a plugin, look in plugin dir
+	} else if strings.HasPrefix(u.Path, "/public/plugins/") {
+		for _, route := range plugins.StaticRoutes {
+			pluginPrefix := filepath.Join("/public/plugins/", route.PluginId)
+			if strings.HasPrefix(u.Path, pluginPrefix) {
+				return &sourceMapLocation{
+					dir:      route.Directory,
+					path:     u.Path[len(pluginPrefix):] + ".map",
+					pluginID: route.PluginId,
+				}, nil
+			}
+		}
+	}
+	return nil, nil
+}
+
+func (store *SourceMapStore) getSourceMap(sourceURL string) (*sourceMap, error) {
+	store.Lock()
+	defer store.Unlock()
+
+	if smap, ok := store.cache[sourceURL]; ok {
+		return smap, nil
+	}
+	sourceMapLocation, err := store.guessSourceMapLocation(sourceURL)
+	if err != nil {
+		return nil, err
+	}
+	if sourceMapLocation == nil {
+		// Cache nil value for sourceURL, since we want to flag that we couldn't guess the map location and not try again
+		store.cache[sourceURL] = nil
+		return nil, nil
+	}
+	path := strings.ReplaceAll(sourceMapLocation.path, "../", "") // just in case
+	b, err := store.readSourceMap(sourceMapLocation.dir, path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			// Cache nil value for sourceURL, since we want to flag that it wasn't found in the filesystem and not try again
+			store.cache[sourceURL] = nil
+			return nil, nil
+		}
+		return nil, err
+	}
+
+	consumer, err := sourcemap.Parse(sourceURL+".map", b)
+	if err != nil {
+		return nil, err
+	}
+	smap := &sourceMap{
+		consumer: consumer,
+		pluginID: sourceMapLocation.pluginID,
+	}
+	store.cache[sourceURL] = smap
+	return smap, nil
+}
+
+func (store *SourceMapStore) resolveSourceLocation(frame sentry.Frame) (*sentry.Frame, error) {
+	smap, err := store.getSourceMap(frame.Filename)
+	if err != nil {
+		return nil, err
+	}
+	if smap == nil {
+		return nil, nil
+	}
+	file, function, line, col, ok := smap.consumer.Source(frame.Lineno, frame.Colno)
+	if !ok {
+		return nil, nil
+	}
+	// unfortunately in many cases go-sourcemap fails to determine the original function name.
+	// not a big issue as long as file, line and column are correct
+	if len(function) == 0 {
+		function = "?"
+	}
+	module := "core"
+	if len(smap.pluginID) > 0 {
+		module = smap.pluginID
+	}
+	return &sentry.Frame{
+		Filename: file,
+		Lineno:   line,
+		Colno:    col,
+		Function: function,
+		Module:   module,
+	}, nil
+}