Merge pull request #18 from infiniteloopcloud/parse-panic

Add panic parser

.github/workflows/golangci-lint.yml

@@ -19,11 +19,11 @@ jobs:
     steps:
       - uses: actions/setup-go@v3
         with:
-          go-version: 1.19
+          go-version: 1.21
       - uses: actions/checkout@v3
       - run: go mod tidy
       - run: go mod vendor
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3
         with:
-          version: v1.50
+          version: v1.55.1

.golangci.yml

@@ -202,7 +202,7 @@ linters-settings:
 
   gosimple:
     # Select the Go version to target. The default is '1.13'.
-    go: "1.16"
+    go: "1.18"
     # https://staticcheck.io/docs/options#checks
     checks: [ "all" ]
 
@@ -230,7 +230,7 @@ linters-settings:
 
   staticcheck:
     # Select the Go version to target. The default is '1.13'.
-    go: "1.16"
+    go: "1.18"
     # https://staticcheck.io/docs/options#checks
     checks: [ "all" ]
 
@@ -273,7 +273,7 @@ linters-settings:
 
   unused:
     # Select the Go version to target. The default is '1.13'.
-    go: "1.16"
+    go: "1.18"
 
 
 linters:

go.mod

@@ -1,6 +1,6 @@
 module github.com/infiniteloopcloud/go
 
-go 1.17
+go 1.18
 
 require (
 	github.com/aws/aws-sdk-go-v2 v1.17.3

middlewares/panicparse.go

@@ -0,0 +1,112 @@
+package middlewares
+
+import (
+	"fmt"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+)
+
+var fileDetails = regexp.MustCompile(`^(/([\w-._]+/)*([\w-]+\.[a-z]+)):(\d+)\s(\+0x[0-9a-fA-F]+$)`)
+var tabsNewlinesRegexp = regexp.MustCompile(`[\t\n]+`)
+
+type stackFlags struct {
+	Vendor  bool
+	Builtin bool
+}
+type stackLine struct {
+	FunctionName  string
+	FilePath      string
+	FilePathShort string
+	LineNumber    int
+	StackPosition string
+	Flags         stackFlags
+}
+
+func (sl stackLine) String() string {
+	return fmt.Sprintf("%s:%d:%s", sl.FilePathShort, sl.LineNumber, sl.FunctionName)
+}
+
+type panicParser struct{}
+
+func (p panicParser) Parse(stack []byte) ([]stackLine, error) {
+	str := strings.TrimSpace(string(stack))
+	// cut the header
+	_, str, _ = strings.Cut(str, "\n")
+	// replace new lines with tabs
+	str = strings.ReplaceAll(str, "\n", "\t")
+	// replace tab duplications with single tabs
+	str = tabsNewlinesRegexp.ReplaceAllString(str, "\t")
+
+	// nolint: prealloc
+	var result []stackLine
+	var tabCounter int
+	var latestTabIndex int
+	for i, r := range []rune(str) {
+		if r != '\t' {
+			// skip chars until reaching a tab
+			continue
+		}
+		tabCounter++
+		if tabCounter%2 != 0 {
+			// every second tab matters, odd tabs will be skipped
+			continue
+		}
+
+		// take the part of the string between the even tabs
+		line := p.substring(str, latestTabIndex, i)
+
+		functionNameParams, fileData, found := strings.Cut(line, "\t")
+		if !found {
+			return nil, fmt.Errorf("error separating function name from file details: %s", line)
+		}
+
+		// remove last (...)
+		functionName, _, found := p.cutLast(functionNameParams, "(")
+		if !found {
+			return nil, fmt.Errorf("error cutting params from the func definition: %s", functionNameParams)
+		}
+
+		fileDetailsRegexResult := fileDetails.FindAllStringSubmatch(fileData, -1)
+		if len(fileDetailsRegexResult) == 0 || len(fileDetailsRegexResult[0]) != 6 {
+			return nil, fmt.Errorf("error parsing file details of the stack line: %s", fileData)
+		}
+
+		lineNum, err := strconv.Atoi(fileDetailsRegexResult[0][4])
+		if err != nil {
+			return nil, fmt.Errorf("error parsing line number: %w", err)
+		}
+
+		groot := runtime.GOROOT()
+		result = append(result, stackLine{
+			FunctionName:  functionName + "(...)",
+			FilePath:      fileDetailsRegexResult[0][1],
+			FilePathShort: fileDetailsRegexResult[0][2] + fileDetailsRegexResult[0][3],
+			LineNumber:    lineNum,
+			StackPosition: fileDetailsRegexResult[0][5],
+			Flags: stackFlags{
+				Vendor:  strings.Contains(fileDetailsRegexResult[0][1], "/vendor/"),
+				Builtin: strings.Contains(fileDetailsRegexResult[0][1], groot),
+			},
+		})
+		latestTabIndex = i
+	}
+
+	return result, nil
+}
+
+func (panicParser) substring(str string, i, j int) string {
+	if i > 0 {
+		i += 1
+	}
+	return str[i:j]
+}
+
+func (panicParser) cutLast(str, sep string) (string, string, bool) {
+	idx := strings.LastIndex(str, sep)
+	if idx < 0 {
+		return str, "", false
+	}
+	return str[:idx], str[idx+1:], true
+}

middlewares/panicparse_test.go

@@ -0,0 +1,85 @@
+package middlewares
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"runtime/debug"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type panicParserWriter struct {
+	b *bytes.Buffer
+}
+
+func (w *panicParserWriter) Write(b []byte) (n int, err error) {
+	w.b.Write(b)
+	w.b.WriteByte(byte('\n'))
+	return len(b) + 1, nil
+}
+
+func TestPanicParser_Parse(t *testing.T) {
+	r := chi.NewRouter()
+
+	var parsed []stackLine
+	oldRecovererErrorWriter := recovererErrorWriter
+	defer func() { recovererErrorWriter = oldRecovererErrorWriter }()
+	w := panicParserWriter{b: bytes.NewBuffer(nil)}
+	recovererErrorWriter = &w
+
+	r.Use(Recoverer)
+	SetPrintPrettyStack(func(ctx context.Context, rvr interface{}) {
+		debugStack := debug.Stack()
+		var err error
+		parsed, err = panicParser{}.Parse(debugStack)
+		if err != nil {
+			os.Stderr.Write(debugStack)
+			return
+		}
+		multilinePrettyPrint(ctx, rvr, parsed)
+	})
+	r.Get("/", panicingHandler)
+
+	ts := httptest.NewServer(r)
+	defer ts.Close()
+
+	res, _ := testRequest(t, ts, "GET", "/", nil)
+	assertEqual(t, res.StatusCode, http.StatusInternalServerError)
+
+	assert.Len(t, parsed, 13)
+
+	var latestPanicID string
+	for _, line := range strings.Split(w.b.String(), "\n") {
+		if line == "" {
+			continue
+		}
+		var logLine map[string]any
+		require.NoError(t, json.Unmarshal([]byte(line), &logLine))
+		panicID, ok := logLine["panic_id"]
+		require.True(t, ok)
+		if latestPanicID == "" {
+			// nolint: errcheck
+			latestPanicID = panicID.(string)
+		} else {
+			assert.Equal(t, latestPanicID, panicID)
+		}
+		lineNum, hasLineField := logLine["line_number"]
+		require.True(t, hasLineField)
+		// nolint: errcheck
+		_, err := strconv.Atoi(lineNum.(string))
+		require.NoError(t, err)
+		_, hasFnName := logLine["function_name"]
+		require.True(t, hasFnName)
+		_, hasFilePath := logLine["file_path"]
+		require.True(t, hasFilePath)
+	}
+}

middlewares/recoverer.go

@@ -12,9 +12,12 @@ import (
 	"net/http"
 	"os"
 	"runtime/debug"
+	"slices"
+	"strconv"
 	"strings"
 
 	"github.com/go-chi/chi/v5/middleware"
+	"github.com/google/uuid"
 	"github.com/infiniteloopcloud/log"
 )
 
@@ -24,6 +27,8 @@ type RecoverParserIface interface {
 
 var RecoverParser RecoverParserIface = prettyStack{}
 
+type PrintPrettyStackFn func(ctx context.Context, rvr interface{})
+
 // Recoverer is a middleware that recovers from panics, logs the panic (and a
 // backtrace), and returns a HTTP 500 (Internal Server Error) status if
 // possible. Recoverer prints a request ID if one is provided.
@@ -44,7 +49,8 @@ func Recoverer(next http.Handler) http.Handler {
 				if logEntry != nil {
 					logEntry.Panic(rvr, debug.Stack())
 				} else {
-					PrintPrettyStack(r.Context(), rvr)
+					// nolint:forbidigo
+					printPrettyStackFn(r.Context(), rvr)
 				}
 
 				w.WriteHeader(http.StatusInternalServerError)
@@ -60,6 +66,8 @@ func Recoverer(next http.Handler) http.Handler {
 // for ability to test the PrintPrettyStack function
 var recovererErrorWriter io.Writer = os.Stderr
 
+var printPrettyStackFn = PrintPrettyStack
+
 func PrintPrettyStack(ctx context.Context, rvr interface{}) {
 	debugStack := debug.Stack()
 	out, err := RecoverParser.Parse(ctx, debugStack, rvr)
@@ -72,6 +80,44 @@ func PrintPrettyStack(ctx context.Context, rvr interface{}) {
 	}
 }
 
+func MultilinePrettyPrintStack(ctx context.Context, rvr interface{}) {
+	debugStack := debug.Stack()
+	parsed, err := panicParser{}.Parse(debugStack)
+	if err != nil {
+		os.Stderr.Write(debugStack)
+		return
+	}
+	multilinePrettyPrint(ctx, rvr, parsed)
+}
+
+func multilinePrettyPrint(ctx context.Context, rvr interface{}, parsed []stackLine) {
+	slices.Reverse(parsed)
+	panicID := uuid.NewString()
+	for _, line := range parsed {
+		logLine := log.Parse(ctx, log.ErrorLevelString, "panic happen",
+			fmt.Errorf("panic happen: %v", rvr),
+			log.Field{
+				Key:   "panic_id",
+				Value: panicID,
+			},
+			log.Field{
+				Key:   "function_name",
+				Value: line.FunctionName,
+			},
+			log.Field{
+				Key:   "file_path",
+				Value: line.FilePath,
+			},
+			log.Field{
+				Key:   "line_number",
+				Value: strconv.Itoa(line.LineNumber),
+			},
+		)
+		// nolint: errcheck
+		recovererErrorWriter.Write([]byte(logLine))
+	}
+}
+
 func SetRecovererErrorWriter(w io.Writer) {
 	recovererErrorWriter = w
 }
@@ -80,6 +126,11 @@ func SetRecoverParser(p RecoverParserIface) {
 	RecoverParser = p
 }
 
+// nolint:forbidigo
+func SetPrintPrettyStack(fn PrintPrettyStackFn) {
+	printPrettyStackFn = fn
+}
+
 type prettyStack struct {
 }