fix: Solve panic on an empty profile ingest (#793)

pkg/convert/parser.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"bytes"
 	"compress/gzip"
+	"fmt"
 	"io"
 	"strconv"
 
@@ -34,8 +35,9 @@ func ParsePprof(r io.Reader) (*tree.Profile, error) {
 	bufioReader := bufio.NewReader(r)
 	header, err := bufioReader.Peek(2)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("unable to read profile file header: %w", err)
 	}
+
 	if header[0] == gzipMagicBytes[0] && header[1] == gzipMagicBytes[1] {
 		r, err = gzip.NewReader(bufioReader)
 		if err != nil {
@@ -49,10 +51,12 @@ func ParsePprof(r io.Reader) (*tree.Profile, error) {
 	if err != nil {
 		return nil, err
 	}
+
 	profile := &tree.Profile{}
 	if err := proto.Unmarshal(b, profile); err != nil {
 		return nil, err
 	}
+
 	return profile, nil
 }
 

pkg/server/ingest.go

@@ -65,17 +65,28 @@ func (h ingestHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		if err == nil {
 			var profile *tree.Profile
 			var prevProfile *tree.Profile
+
 			f, _, err := r.FormFile("profile")
-			if err == nil {
-				profile, err = convert.ParsePprof(f)
+			if err != nil {
+				WriteError(h.log, w, http.StatusInternalServerError, err, "error happened while getting profile file")
+				return
+			}
+
+			profile, err = convert.ParsePprof(f)
+			if err != nil {
+				WriteError(h.log, w, http.StatusInternalServerError, err, "error happened while parsing profile file")
+				return
 			}
+
 			f, _, err = r.FormFile("prev_profile")
 			if err == nil {
 				prevProfile, err = convert.ParsePprof(f)
+				if err != nil {
+					WriteError(h.log, w, http.StatusInternalServerError, err, "error happened while parsing prev_profile file")
+					return
+				}
 			}
 
-			// TODO: add error handling for all of these
-
 			for _, sampleTypeStr := range profile.SampleTypes() {
 				var t *tree.SampleTypeConfig
 				var ok bool