feat: Fast stdin display, lower memory usage, follow/reverse mode, home/end key support. long help support (#85)

Signed-off-by: Hiram Chirino <[email protected]>
Co-authored-by: Maksym Kryvchun <[email protected]>

Author: chirino

.gitignore

@@ -8,6 +8,7 @@ bin
 
 # IDE
 .vscode
+.idea
 
 # Test binary, built with `go test -c`
 *.test

.golangci.json

@@ -25,13 +25,18 @@
       "ireturn",
       "gomoddirectives",
       "execinquery",
-      "tagalign"
+      "tagalign",
+      "mnd",
+      "nlreturn"
     ]
   },
   "linters-settings": {
     "goimports": {
       "local-prefixes": "github.com/hedhyw/json-log-viewer/"
     },
+    "cyclop": {
+      "max-complexity": 15
+    },
     "revive": {}
   }
 }

Makefile

@@ -33,6 +33,11 @@ lint: bin/golangci-lint-${GOLANG_CI_LINT_VER}
 	./bin/golangci-lint-${GOLANG_CI_LINT_VER} run
 .PHONY: lint
 
+fix: bin/golangci-lint-${GOLANG_CI_LINT_VER}
+	 gofumpt -l -w .
+	./bin/golangci-lint-${GOLANG_CI_LINT_VER} run --fix
+.PHONY: lint-fix
+
 test:
 	go test \
 		-coverpkg=${COVER_PACKAGES} \

README.md

@@ -75,16 +75,19 @@ docker logs -f 000000000000 2>&1 | jlv
 
 ### Hotkeys
 
-| Key    | Action         |
-| ------ | -------------- |
-| Enter  | Open/Close log |
-| F      | Filter         |
-| Ctrl+C | Exit           |
-| F10    | Exit           |
-| Esc    | Back           |
-| ↑↓     | Navigation     |
-
-> \[↑\] Click Up on the first row to reload the file.
+| Key    | Action            |
+|--------|-------------------|
+| Enter  | Open log          |
+| Esc    | Back              |
+| F      | Filter            |
+| R      | Reverse           |
+| Ctrl+C | Exit              |
+| F10    | Exit              |
+| ↑↓     | Line Up / Down    |
+| Home   | Navigate to Start |
+| End    | Navigate to End   |
+
+> Attempting to navigate past the last line in the log will put you in follow mode.
 
 ## Install
 

assets/jlv.log

@@ -0,0 +1 @@
+time=2024-08-19T15:06:16.848-04:00 level=INFO msg="case <-eofEvent"

cmd/jlv/main.go

@@ -1,20 +1,18 @@
 package main
 
 import (
-	"bytes"
+	"context"
 	"flag"
 	"fmt"
-	"io/fs"
 	"os"
 	"path"
 
 	tea "github.com/charmbracelet/bubbletea"
 
 	"github.com/hedhyw/json-log-viewer/internal/app"
 	"github.com/hedhyw/json-log-viewer/internal/pkg/config"
+	"github.com/hedhyw/json-log-viewer/internal/pkg/events"
 	"github.com/hedhyw/json-log-viewer/internal/pkg/source"
-	"github.com/hedhyw/json-log-viewer/internal/pkg/source/fileinput"
-	"github.com/hedhyw/json-log-viewer/internal/pkg/source/readerinput"
 )
 
 // version will be set on build.
@@ -39,41 +37,54 @@ func main() {
 		fatalf("Error reading config: %s\n", err)
 	}
 
-	var sourceInput source.Input
+	fileName := ""
+	var inputSource *source.Source
 
 	switch flag.NArg() {
 	case 0:
-		sourceInput, err = getStdinSource(cfg, os.Stdin)
+		// Tee stdin to a temp file, so that we can
+		// lazy load the log entries using random access.
+		fileName = "-"
+
+		stdIn, err := getStdinReader(os.Stdin)
 		if err != nil {
 			fatalf("Stdin: %s\n", err)
 		}
+
+		inputSource, err = source.Reader(stdIn, cfg)
+		if err != nil {
+			fatalf("Could not create temp flie: %s\n", err)
+		}
+		defer inputSource.Close()
+
 	case 1:
-		sourceInput = fileinput.New(flag.Arg(0))
+		fileName = flag.Arg(0)
+		inputSource, err = source.File(fileName, cfg)
+		if err != nil {
+			fatalf("Could not create temp flie: %s\n", err)
+		}
+		defer inputSource.Close()
+
 	default:
 		fatalf("Invalid arguments, usage: %s file.log\n", os.Args[0])
 	}
 
-	appModel := app.NewModel(sourceInput, cfg, version)
+	appModel := app.NewModel(fileName, cfg, version)
 	program := tea.NewProgram(appModel, tea.WithInputTTY(), tea.WithAltScreen())
 
+	inputSource.StartStreaming(context.Background(), func(entries source.LazyLogEntries, err error) {
+		if err != nil {
+			program.Send(events.ErrorOccuredMsg{Err: err})
+		} else {
+			program.Send(events.LogEntriesUpdateMsg(entries))
+		}
+	})
+
 	if _, err := program.Run(); err != nil {
 		fatalf("Error running program: %s\n", err)
 	}
 }
 
-func getStdinSource(cfg *config.Config, defaultInput fs.File) (source.Input, error) {
-	stat, err := defaultInput.Stat()
-	if err != nil {
-		return nil, fmt.Errorf("stat: %w", err)
-	}
-
-	if stat.Mode()&os.ModeCharDevice != 0 {
-		return readerinput.New(bytes.NewReader(nil), cfg.StdinReadTimeout), nil
-	}
-
-	return readerinput.New(defaultInput, cfg.StdinReadTimeout), nil
-}
-
 func fatalf(message string, args ...any) {
 	fmt.Fprintf(os.Stderr, message, args...)
 	os.Exit(1)

cmd/jlv/main_test.go

@@ -2,24 +2,19 @@ package main
 
 import (
 	"bytes"
-	"context"
 	"errors"
 	"io"
 	"io/fs"
 	"os"
 	"testing"
 
-	"github.com/hedhyw/json-log-viewer/internal/pkg/config"
-
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
 func TestGetStdinSource(t *testing.T) {
 	t.Parallel()
 
-	ctx := context.Background()
-
 	t.Run("ModeNamedPipe", func(t *testing.T) {
 		t.Parallel()
 
@@ -32,15 +27,10 @@ func TestGetStdinSource(t *testing.T) {
 			},
 		}
 
-		input, err := getStdinSource(config.GetDefaultConfig(), file)
-		require.NoError(t, err)
-
-		readCloser, err := input.ReadCloser(ctx)
+		input, err := getStdinReader(file)
 		require.NoError(t, err)
 
-		t.Cleanup(func() { assert.NoError(t, readCloser.Close()) })
-
-		data, err := io.ReadAll(readCloser)
+		data, err := io.ReadAll(input)
 		require.NoError(t, err)
 		assert.Equal(t, content, string(data))
 	})
@@ -55,15 +45,10 @@ func TestGetStdinSource(t *testing.T) {
 			},
 		}
 
-		input, err := getStdinSource(config.GetDefaultConfig(), file)
-		require.NoError(t, err)
-
-		readCloser, err := input.ReadCloser(ctx)
+		input, err := getStdinReader(file)
 		require.NoError(t, err)
 
-		t.Cleanup(func() { assert.NoError(t, readCloser.Close()) })
-
-		data, err := io.ReadAll(readCloser)
+		data, err := io.ReadAll(input)
 		require.NoError(t, err)
 		assert.Empty(t, data)
 	})
@@ -76,7 +61,7 @@ func TestGetStdinSource(t *testing.T) {
 
 		file := fakeFile{ErrStat: errStat}
 
-		_, err := getStdinSource(config.GetDefaultConfig(), file)
+		_, err := getStdinReader(file)
 		require.Error(t, err)
 		require.ErrorIs(t, err, errStat)
 	})

cmd/jlv/stdin_reader.go

@@ -0,0 +1,24 @@
+//go:build !mock_stdin
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+)
+
+func getStdinReader(defaultInput fs.File) (io.Reader, error) {
+	stat, err := defaultInput.Stat()
+	if err != nil {
+		return nil, fmt.Errorf("stat: %w", err)
+	}
+
+	if stat.Mode()&os.ModeCharDevice != 0 {
+		return bytes.NewReader(nil), nil
+	}
+
+	return defaultInput, nil
+}

cmd/jlv/stdin_reader_mock.go

@@ -0,0 +1,30 @@
+//go:build mock_stdin
+
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"time"
+)
+
+func getStdinReader(defaultInput fs.File) (io.Reader, error) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		return nil, fmt.Errorf("pipe: %w", err)
+	}
+	go func() {
+		defer w.Close()
+		for i := 0; ; i++ {
+			_, err := w.Write([]byte(fmt.Sprintf(`{"message": "Line %d"}
+	`, i)))
+			if err != nil {
+				fatalf("Write failed: %s\n", err)
+			}
+			time.Sleep(10 * time.Millisecond)
+		}
+	}()
+	return r, nil
+}

example.jlv.jsonc

@@ -63,13 +63,7 @@
         "50": "error",
         "60": "fatal"
     },
-    // The number of rows to pre-render.
-    "prerenderRows": 100,
-    // The number nanoseconds between manual file reloads.
-    "reloadThreshold": 1000000000,
     // The maximum size of the file in bytes.
     // The rest of the file will be ignored.
     "maxFileSizeBytes": 1073741824,
-    // StdinReadTimeout is the timeout (in nanoseconds) of reading from the standart input.
-    "stdinReadTimeout": 1000000000
 }