clearer separation of concerns when bootstrapping application

3 files changed, 138 insertions, 0 deletions

diff --git a/pkg/logs/logs.go b/pkg/logs/logs.go
new file mode 100644
index 000000000..a4fe94031
--- /dev/null
+++ b/pkg/logs/logs.go
@@ -0,0 +1,34 @@
+package logs
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/aybabtme/humanlog"
+	"github.com/jesseduffield/lazygit/pkg/config"
+)
+
+// TailLogs lets us run `lazygit --logs` to print the logs produced by other lazygit processes.
+// This makes for easier debugging.
+func TailLogs() {
+	logFilePath, err := config.LogPath()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Printf("Tailing log file %s\n\n", logFilePath)
+
+	opts := humanlog.DefaultOptions
+	opts.Truncates = false
+
+	_, err = os.Stat(logFilePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			log.Fatal("Log file does not exist. Run `lazygit --debug` first to create the log file")
+		}
+		log.Fatal(err)
+	}
+
+	TailLogsForPlatform(logFilePath, opts)
+}
diff --git a/pkg/logs/logs_default.go b/pkg/logs/logs_default.go
new file mode 100644
index 000000000..b4474720c
--- /dev/null
+++ b/pkg/logs/logs_default.go
@@ -0,0 +1,31 @@
+//go:build !windows
+// +build !windows
+
+package logs
+
+import (
+	"log"
+	"os"
+
+	"github.com/aybabtme/humanlog"
+	"github.com/jesseduffield/lazygit/pkg/secureexec"
+)
+
+func TailLogsForPlatform(logFilePath string, opts *humanlog.HandlerOptions) {
+	cmd := secureexec.Command("tail", "-f", logFilePath)
+
+	stdout, _ := cmd.StdoutPipe()
+	if err := cmd.Start(); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := humanlog.Scanner(stdout, os.Stdout, opts); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := cmd.Wait(); err != nil {
+		log.Fatal(err)
+	}
+
+	os.Exit(0)
+}
diff --git a/pkg/logs/logs_windows.go b/pkg/logs/logs_windows.go
new file mode 100644
index 000000000..7fa17db26
--- /dev/null
+++ b/pkg/logs/logs_windows.go
@@ -0,0 +1,73 @@
+//go:build windows
+// +build windows
+
+package logs
+
+import (
+	"bufio"
+	"log"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/aybabtme/humanlog"
+)
+
+func TailLogsForPlatform(logFilePath string, opts *humanlog.HandlerOptions) {
+	var lastModified int64 = 0
+	var lastOffset int64 = 0
+	for {
+		stat, err := os.Stat(logFilePath)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if stat.ModTime().Unix() > lastModified {
+			err = TailFrom(lastOffset, logFilePath, opts)
+			if err != nil {
+				log.Fatal(err)
+			}
+		}
+		lastOffset = stat.Size()
+		time.Sleep(1 * time.Second)
+	}
+}
+
+func OpenAndSeek(filepath string, offset int64) (*os.File, error) {
+	file, err := os.Open(filepath)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = file.Seek(offset, 0)
+	if err != nil {
+		_ = file.Close()
+		return nil, err
+	}
+	return file, nil
+}
+
+func TailFrom(lastOffset int64, logFilePath string, opts *humanlog.HandlerOptions) error {
+	file, err := OpenAndSeek(logFilePath, lastOffset)
+	if err != nil {
+		return err
+	}
+
+	fileScanner := bufio.NewScanner(file)
+	var lines []string
+	for fileScanner.Scan() {
+		lines = append(lines, fileScanner.Text())
+	}
+	file.Close()
+	lineCount := len(lines)
+	lastTen := lines
+	if lineCount > 10 {
+		lastTen = lines[lineCount-10:]
+	}
+	for _, line := range lastTen {
+		reader := strings.NewReader(line)
+		if err := humanlog.Scanner(reader, os.Stdout, opts); err != nil {
+			log.Fatal(err)
+		}
+	}
+	return nil
+}