history: add UI view to traces

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/tonistiigi/jaeger-ui-rest/server.go

@@ -0,0 +1,172 @@
+package jaegerui
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+	"sync"
+
+	"github.com/pkg/errors"
+)
+
+func NewServer(cfg Config) *Server {
+	mux := &http.ServeMux{}
+	s := &Server{
+		config: cfg,
+		server: &http.Server{
+			Handler: mux,
+		},
+	}
+
+	fsHandler := http.FileServer(FS(cfg))
+
+	mux.HandleFunc("GET /api/services", func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte(`{"data": [], "total": 0}`))
+	})
+	mux.HandleFunc("GET /trace/", redirectRoot(fsHandler))
+	mux.HandleFunc("GET /search", redirectRoot(fsHandler))
+
+	mux.HandleFunc("POST /api/traces/", func(w http.ResponseWriter, r *http.Request) {
+		traceID := strings.TrimPrefix(r.URL.Path, "/api/traces/")
+		if traceID == "" || strings.Contains(traceID, "/") {
+			http.Error(w, "Invalid trace ID", http.StatusBadRequest)
+			return
+		}
+		handleHTTPError(s.AddTrace(traceID, r.Body), w)
+	})
+
+	mux.HandleFunc("GET /api/traces/", func(w http.ResponseWriter, r *http.Request) {
+		traceID := strings.TrimPrefix(r.URL.Path, "/api/traces/")
+		if traceID == "" {
+			qry := r.URL.Query()
+			ids := qry["traceID"]
+			if len(ids) > 0 {
+				dt, err := s.GetTraces(ids...)
+				if err != nil {
+					handleHTTPError(err, w)
+					return
+				}
+				w.Write(dt)
+				return
+			}
+		}
+
+		if traceID == "" || strings.Contains(traceID, "/") {
+			http.Error(w, "Invalid trace ID", http.StatusBadRequest)
+			return
+		}
+		dt, err := s.GetTraces(traceID)
+		if err != nil {
+			handleHTTPError(err, w)
+			return
+		}
+		w.Write(dt)
+	})
+
+	mux.Handle("/", fsHandler)
+
+	return s
+}
+
+type Server struct {
+	config Config
+	server *http.Server
+
+	mu     sync.Mutex
+	traces map[string][]byte
+}
+
+func (s *Server) AddTrace(traceID string, rdr io.Reader) error {
+	var payload struct {
+		Data []struct {
+			TraceID string `json:"traceID"`
+		} `json:"data"`
+	}
+	buf := &bytes.Buffer{}
+	if _, err := io.Copy(buf, rdr); err != nil {
+		return errors.Wrapf(err, "failed to read trace data")
+	}
+	dt := buf.Bytes()
+
+	if err := json.Unmarshal(dt, &payload); err != nil {
+		return errors.Wrapf(err, "failed to unmarshal trace data")
+	}
+
+	if len(payload.Data) != 1 {
+		return errors.Errorf("expected 1 trace, got %d", len(payload.Data))
+	}
+
+	if payload.Data[0].TraceID != traceID {
+		return errors.Errorf("trace ID mismatch: %s != %s", payload.Data[0].TraceID, traceID)
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.traces == nil {
+		s.traces = make(map[string][]byte)
+	}
+	s.traces[traceID] = dt
+	return nil
+}
+
+func (s *Server) GetTraces(traceIDs ...string) ([]byte, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if len(traceIDs) == 0 {
+		return nil, errors.Errorf("trace ID is required")
+	}
+
+	if len(traceIDs) == 1 {
+		dt, ok := s.traces[traceIDs[0]]
+		if !ok {
+			return nil, errors.Wrapf(os.ErrNotExist, "trace %s not found", traceIDs[0])
+		}
+		return dt, nil
+	}
+
+	type payloadT struct {
+		Data []interface{} `json:"data"`
+	}
+	var payload payloadT
+
+	for _, traceID := range traceIDs {
+		dt, ok := s.traces[traceID]
+		if !ok {
+			return nil, errors.Wrapf(os.ErrNotExist, "trace %s not found", traceID)
+		}
+		var p payloadT
+		if err := json.Unmarshal(dt, &p); err != nil {
+			return nil, errors.Wrapf(err, "failed to unmarshal trace data")
+		}
+		payload.Data = append(payload.Data, p.Data...)
+	}
+
+	return json.MarshalIndent(payload, "", "  ")
+}
+
+func (s *Server) Serve(l net.Listener) error {
+	return s.server.Serve(l)
+}
+
+func redirectRoot(h http.Handler) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		r.URL.Path = "/"
+		h.ServeHTTP(w, r)
+	}
+}
+
+func handleHTTPError(err error, w http.ResponseWriter) {
+	switch {
+	case err == nil:
+		return
+	case errors.Is(err, os.ErrNotExist):
+		http.Error(w, err.Error(), http.StatusNotFound)
+	default:
+		http.Error(w, err.Error(), http.StatusBadRequest)
+	}
+}