feat: summarize to use errors instead of panics

Signed-off-by: Andres Taylor <[email protected]>

go/summarize/force-graph.go

@@ -18,6 +18,7 @@ package summarize
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"html/template"
 	"net"
@@ -132,43 +133,43 @@ func createGraphKey(tableA, tableB string) graphKey {
 	return graphKey{Tbl1: tableB, Tbl2: tableA}
 }
 
-func renderQueryGraph(s *Summary) {
+func renderQueryGraph(s *Summary) error {
 	data := createForceGraphData(s)
 
 	listener, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {
-		panic(err)
+		return fmt.Errorf("could not create a listener: %w", err)
 	}
 	defer listener.Close()
 
 	// Get the assigned port
 	addr, ok := listener.Addr().(*net.TCPAddr)
 	if !ok {
-		exit("could not create a listener")
+		return errors.New("could not create a listener")
 	}
 	fmt.Printf("Server started at http://localhost:%d\nExit the program with CTRL+C\n", addr.Port)
 
 	// Start the server
 	// nolint: gosec,nolintlint // this is all ran locally so no need to care about vulnerabilities around timeouts
-	err = http.Serve(listener, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-		serveIndex(w, data)
+	return http.Serve(listener, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		err := serveIndex(w, data)
+		if err != nil {
+			fmt.Println(err.Error())
+		}
 	}))
-	if err != nil {
-		exit(err.Error())
-	}
 }
 
 // Function to dynamically generate and serve index.html
-func serveIndex(w http.ResponseWriter, data forceGraphData) {
+func serveIndex(w http.ResponseWriter, data forceGraphData) error {
 	dataBytes, err := json.Marshal(data.data)
 	if err != nil {
-		exit(err.Error())
+		return fmt.Errorf("could not marshal data: %w", err)
 	}
 
 	tmpl, err := template.New("index").Parse(templateHTML)
 	if err != nil {
 		http.Error(w, "Failed to parse template", http.StatusInternalServerError)
-		return
+		return err
 	}
 
 	d := struct {
@@ -182,8 +183,10 @@ func serveIndex(w http.ResponseWriter, data forceGraphData) {
 
 	if err := tmpl.Execute(w, d); err != nil {
 		http.Error(w, "Failed to execute template", http.StatusInternalServerError)
-		return
+		return err
 	}
+
+	return nil
 }
 
 /*

go/summarize/markdown.go

@@ -80,7 +80,13 @@ func renderHotQueries(md *markdown.MarkDown, queries []keys.QueryAnalysisResult,
 	}
 }
 
-func renderTableUsage(md *markdown.MarkDown, tableSummaries []*TableSummary, includeRowCount bool) {
+func renderTableUsage(md *markdown.MarkDown, in []*TableSummary, includeRowCount bool) {
+	var tableSummaries []*TableSummary
+	for _, tbl := range in {
+		if !tbl.IsEmpty() {
+			tableSummaries = append(tableSummaries, tbl)
+		}
+	}
 	if len(tableSummaries) == 0 {
 		return
 	}

go/summarize/reading.go

@@ -18,6 +18,7 @@ package summarize
 
 import (
 	"encoding/json"
+	"fmt"
 	"os"
 	"sort"
 	"strconv"
@@ -27,10 +28,10 @@ import (
 	"github.com/vitessio/vt/go/transactions"
 )
 
-func readTracedFile(fileName string) traceSummary {
+func readTracedFile(fileName string) (traceSummary, error) {
 	c, err := os.ReadFile(fileName)
 	if err != nil {
-		exit("Error opening file: " + err.Error())
+		return traceSummary{}, fmt.Errorf("error opening file: %w", err)
 	}
 
 	type traceOutput struct {
@@ -40,7 +41,7 @@ func readTracedFile(fileName string) traceSummary {
 	var to traceOutput
 	err = json.Unmarshal(c, &to)
 	if err != nil {
-		exit("Error parsing json: " + err.Error())
+		return traceSummary{}, fmt.Errorf("error parsing json: %w", err)
 	}
 
 	sort.Slice(to.Queries, func(i, j int) bool {
@@ -58,13 +59,15 @@ func readTracedFile(fileName string) traceSummary {
 	return traceSummary{
 		Name:          fileName,
 		TracedQueries: to.Queries,
-	}
+	}, nil
 }
 
-func readTransactionFile(fileName string) func(s *Summary) error {
+type summarizer = func(s *Summary) error
+
+func readTransactionFile(fileName string) (summarizer, error) {
 	c, err := os.ReadFile(fileName)
 	if err != nil {
-		exit("Error opening file: " + err.Error())
+		return nil, fmt.Errorf("error opening file: %w", err)
 	}
 
 	type txOutput struct {
@@ -75,37 +78,36 @@ func readTransactionFile(fileName string) func(s *Summary) error {
 	var to txOutput
 	err = json.Unmarshal(c, &to)
 	if err != nil {
-		exit("Error parsing json: " + err.Error())
+		return nil, fmt.Errorf("error parsing json: %w", err)
 	}
 	return func(s *Summary) error {
 		s.analyzedFiles = append(s.analyzedFiles, fileName)
 		return summarizeTransactions(s, to.Signatures)
-	}
+	}, nil
 }
 
-func readKeysFile(fileName string) func(s *Summary) error {
+func readKeysFile(fileName string) (summarizer, error) {
 	c, err := os.ReadFile(fileName)
 	if err != nil {
-		exit("Error opening file: " + err.Error())
+		return nil, fmt.Errorf("error opening file: %w", err)
 	}
 
 	var ko keys.Output
 	err = json.Unmarshal(c, &ko)
 	if err != nil {
-		exit("Error parsing json: " + err.Error())
+		return nil, fmt.Errorf("error parsing json: %w", err)
 	}
 
 	return func(s *Summary) error {
 		s.analyzedFiles = append(s.analyzedFiles, fileName)
-		summarizeKeysQueries(s, &ko)
-		return nil
-	}
+		return summarizeKeysQueries(s, &ko)
+	}, nil
 }
 
-func readDBInfoFile(fileName string) func(s *Summary) error {
+func readDBInfoFile(fileName string) (summarizer, error) {
 	schemaInfo, err := dbinfo.Load(fileName)
 	if err != nil {
-		panic(err)
+		return nil, fmt.Errorf("error parsing dbinfo: %w", err)
 	}
 
 	return func(s *Summary) error {
@@ -120,5 +122,5 @@ func readDBInfoFile(fileName string) func(s *Summary) error {
 			table.RowCount = ti.Rows
 		}
 		return nil
-	}
+	}, nil
 }

go/summarize/reading_test.go

@@ -20,9 +20,11 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestReadTransaction(t *testing.T) {
-	file := readTransactionFile("../testdata/small-slow-query-transactions.json")
+	file, err := readTransactionFile("../testdata/small-slow-query-transactions.json")
+	require.NoError(t, err)
 	assert.NotNil(t, file)
 }

go/summarize/summarize-keys.go

@@ -85,7 +85,7 @@ func (p Position) String() string {
 		return "GROUP"
 	}
 
-	panic("unknown Position")
+	return "UNKNOWN"
 }
 
 func (ci ColumnInformation) String() string {
@@ -139,31 +139,30 @@ func (ts TableSummary) UseCount() int {
 
 type getMetric = func(q keys.QueryAnalysisResult) float64
 
-func getMetricForHotness(metric string) getMetric {
+func getMetricForHotness(metric string) (getMetric, error) {
 	switch metric {
 	case "usage-count":
 		return func(q keys.QueryAnalysisResult) float64 {
 			return float64(q.UsageCount)
-		}
+		}, nil
 	case "total-rows-examined":
 		return func(q keys.QueryAnalysisResult) float64 {
 			return float64(q.RowsExamined)
-		}
+		}, nil
 	case "avg-rows-examined":
 		return func(q keys.QueryAnalysisResult) float64 {
 			return float64(q.RowsExamined) / float64(q.UsageCount)
-		}
+		}, nil
 	case "total-time", "":
 		return func(q keys.QueryAnalysisResult) float64 {
 			return q.QueryTime
-		}
+		}, nil
 	case "avg-time":
 		return func(q keys.QueryAnalysisResult) float64 {
 			return q.QueryTime / float64(q.UsageCount)
-		}
+		}, nil
 	default:
-		exit(fmt.Sprintf("unknown metric: %s", metric))
-		panic("unreachable")
+		return nil, fmt.Errorf("unknown metric: %s", metric)
 	}
 }
 
@@ -185,7 +184,7 @@ func makeKey(lhs, rhs operators.Column) graphKey {
 	return graphKey{rhs.Table, lhs.Table}
 }
 
-func summarizeKeysQueries(summary *Summary, queries *keys.Output) {
+func summarizeKeysQueries(summary *Summary, queries *keys.Output) error {
 	tableSummaries := make(map[string]*TableSummary)
 	tableUsageWriteCounts := make(map[string]int)
 	tableUsageReadCounts := make(map[string]int)
@@ -218,11 +217,11 @@ func summarizeKeysQueries(summary *Summary, queries *keys.Output) {
 		table.ReadQueryCount = tblSummary.ReadQueryCount
 		table.WriteQueryCount = tblSummary.WriteQueryCount
 		if table.ColumnUses != nil {
-			panic("ColumnUses already set for table" + tblSummary.Table)
+			return fmt.Errorf("ColumnUses already set for table %s", tblSummary.Table)
 		}
 		table.ColumnUses = tblSummary.ColumnUses
 		if table.JoinPredicates != nil {
-			panic("JoinPredicates already set for table" + tblSummary.Table)
+			return fmt.Errorf("JoinPredicates already set for table %s", tblSummary.Table)
 		}
 		table.JoinPredicates = tblSummary.JoinPredicates
 	}
@@ -269,6 +268,7 @@ func summarizeKeysQueries(summary *Summary, queries *keys.Output) {
 		}
 		return summary.joins[i].Tbl2 < summary.joins[j].Tbl2
 	})
+	return nil
 }
 
 func checkQueryForHotness(hotQueries *[]keys.QueryAnalysisResult, query keys.QueryAnalysisResult, metricReader getMetric) {

go/summarize/summarize-keys_test.go

@@ -70,18 +70,23 @@ func TestSummarizeKeysFile(t *testing.T) {
 	sb := &strings.Builder{}
 	now := time.Date(2024, time.January, 1, 1, 2, 3, 0, time.UTC)
 
-	fnKeys := readKeysFile("../testdata/keys-log.json")
-	fnSchemaInfo := readDBInfoFile("../testdata/keys-schema-info.json")
+	fnKeys, err := readKeysFile("../testdata/keys-log.json")
+	require.NoError(t, err)
+
+	fnSchemaInfo, err := readDBInfoFile("../testdata/keys-schema-info.json")
+	require.NoError(t, err)
 
-	s := NewSummary("")
+	s, err := NewSummary("")
+	require.NoError(t, err)
 
-	err := fnKeys(s)
+	err = fnKeys(s)
 	require.NoError(t, err)
 
 	err = fnSchemaInfo(s)
 	require.NoError(t, err)
 
-	s.PrintMarkdown(sb, now)
+	err = s.PrintMarkdown(sb, now)
+	require.NoError(t, err)
 
 	expected, err := os.ReadFile("../testdata/keys-summary.md")
 	require.NoError(t, err)
@@ -102,16 +107,19 @@ func TestSummarizeKeysWithHotnessFile(t *testing.T) {
 
 	for _, metric := range tests {
 		t.Run(metric, func(t *testing.T) {
-			fn := readKeysFile("../testdata/bigger_slow_query_log.json")
+			fn, err := readKeysFile("../testdata/bigger_slow_query_log.json")
+			require.NoError(t, err)
 			sb := &strings.Builder{}
 			now := time.Date(2024, time.January, 1, 1, 2, 3, 0, time.UTC)
 
-			s := NewSummary(metric)
+			s, err := NewSummary(metric)
+			require.NoError(t, err)
 
-			err := fn(s)
+			err = fn(s)
 			require.NoError(t, err)
 
-			s.PrintMarkdown(sb, now)
+			err = s.PrintMarkdown(sb, now)
+			require.NoError(t, err)
 
 			expected, err := os.ReadFile(fmt.Sprintf("../testdata/bigger_slow_log_%s.md", metric))
 			require.NoError(t, err)

go/summarize/summarize-trace_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func tf1() traceSummary {
@@ -183,7 +184,8 @@ Summary:
 }
 
 func TestSummarizeTraceFile(t *testing.T) {
-	tq := readTracedFile("../testdata/trace-log.json")
+	tq, err := readTracedFile("../testdata/trace-log.json")
+	require.NoError(t, err)
 	sb := &strings.Builder{}
 	printTraceSummary(sb, 80, noHighlight, tq)
 	expected := `Query: INSERT INTO region (R_REGIONKEY, R_NAME, R_COMMENT) VALUES (1, 'ASIA',...

go/summarize/summarize-transactions_test.go

@@ -30,14 +30,17 @@ func TestSummarizeTransactionsFile(t *testing.T) {
 	sb := &strings.Builder{}
 	now := time.Date(2024, time.January, 1, 1, 2, 3, 0, time.UTC)
 
-	fnTx := readTransactionFile("../testdata/small-slow-query-transactions.json")
+	fnTx, err := readTransactionFile("../testdata/small-slow-query-transactions.json")
+	require.NoError(t, err)
 
-	s := NewSummary("")
+	s, err := NewSummary("")
+	require.NoError(t, err)
 
-	err := fnTx(s)
+	err = fnTx(s)
 	require.NoError(t, err)
 
-	s.PrintMarkdown(sb, now)
+	err = s.PrintMarkdown(sb, now)
+	require.NoError(t, err)
 
 	expected, err := os.ReadFile("../testdata/transactions-summary.md")
 	require.NoError(t, err)