initial commit

README.md

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+# applog
+
+applog is a opinionated logger configuration.

applog.go

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+package applog
+
+import (
+	"fmt"
+	"io"
+	"log/slog"
+	"os"
+	"time"
+
+	"gitea.auvem.com/go-toolkit/app"
+	"github.com/lmittmann/tint"
+	slogmulti "github.com/samber/slog-multi"
+)
+
+// ModuleName is the name of the module provided by applog.
+const ModuleName = "app logger"
+
+var (
+	// logfile is the file handle for the log file, if any.
+	logfile *os.File
+)
+
+// AppLogOpts contains options for configuring the application logger.
+type AppLogOpts struct {
+	// Verbose enables verbose logging, which will use the LogOutput writer
+	// for pretty-printed console output. If false, console output is disabled.
+	Verbose bool
+
+	// LogOutput is the output writer for the pretty-printed slog console
+	// logger that is enabled if Verbose is set to true. If nil, console
+	// output will be disabled.
+	LogOutput io.Writer
+
+	// LogFile is the file where JSON formatted logs will be written. If
+	// empty, log file output will be disabled.
+	LogFile string
+
+	// SetDefault indicates whether to set the logger as the default logger
+	// for slog. Generally not recommended.
+	SetDefault bool
+}
+
+// Module creates a new Module instance.
+func (opts AppLogOpts) Module() *app.Module {
+	return app.NewModule(ModuleName, app.ModuleOpts{
+		Setup: func(m *app.Module) error {
+			if opts.LogFile == "" && (opts.LogOutput == nil || !opts.Verbose) {
+				return fmt.Errorf("no logging output configured")
+			}
+
+			output := opts.LogOutput
+			if !opts.Verbose {
+				output = nil
+			}
+
+			if err := setupLogger(m.Lifecycle(), opts.LogFile, output); err != nil {
+				return fmt.Errorf("failed to set up logger: %w", err)
+			}
+
+			if opts.SetDefault {
+				slog.SetDefault(m.Logger())
+			}
+
+			return nil
+		},
+		Teardown: func(m *app.Module) error {
+			teardownLogger()
+			return nil
+		},
+	})
+}
+
+// Module creates a new Module instance for the application logger with the
+// provided options.
+func Module(opts AppLogOpts) *app.Module {
+	return opts.Module()
+}
+
+// setupLogger initializes the multi logger with a JSON handler for file output
+// and a tint handler for pretty-printed console output. May return an error
+// if the log file cannot be opened. Log file should be created if it does not
+// exist and appended to if it does.
+func setupLogger(lifecycle *app.Lifecycle, logFilePath string, logoutput io.Writer) error {
+	handlers := make([]slog.Handler, 0)
+
+	// If log file is specified, set up JSON file logging
+	if logFilePath != "" {
+		var err error
+		logfile, err = os.OpenFile(logFilePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			return err
+		}
+
+		handlers = append(handlers, slog.NewJSONHandler(logfile, &slog.HandlerOptions{}))
+	}
+
+	// If log output is specified, set up pretty-printed console logging
+	if logoutput != nil {
+		handlers = append(handlers, tint.NewHandler(logoutput, &tint.Options{
+			Level:      slog.LevelDebug,
+			TimeFormat: time.Kitchen,
+		}))
+	}
+
+	logger := slog.New(
+		slogmulti.Fanout(handlers...),
+	)
+	lifecycle.WithLogger(logger)
+
+	return nil
+}
+
+// teardownLogger flushes and closes the log file handle.
+func teardownLogger() {
+	// If logfile is nil, nothing to do
+	if logfile == nil {
+		return
+	}
+
+	// Flush the logger to ensure all logs are written
+	if err := logfile.Sync(); err != nil {
+		slog.Error("Error flushing log file", "err", err)
+	}
+
+	// Close log file handle
+	if err := logfile.Close(); err != nil {
+		slog.Error("Error closing log file", "err", err)
+	}
+}

go.mod

@@ -0,0 +1,14 @@
+module gitea.auvem.com/go-toolkit/applog
+
+go 1.24.0
+
+require (
+	gitea.auvem.com/go-toolkit/app v0.0.0-20250603235859-6f9e3731acf9
+	github.com/lmittmann/tint v1.1.1
+	github.com/samber/slog-multi v1.4.0
+)
+
+require (
+	github.com/samber/lo v1.49.1 // indirect
+	golang.org/x/text v0.21.0 // indirect
+)

go.sum

@@ -0,0 +1,18 @@
+gitea.auvem.com/go-toolkit/app v0.0.0-20250603235859-6f9e3731acf9 h1:MYOI+bB4IBAqoL1tyIUFnu0S+NSq0OX88J3K/PUR7lI=
+gitea.auvem.com/go-toolkit/app v0.0.0-20250603235859-6f9e3731acf9/go.mod h1:a7ENpOxndUdONE6oZ9MZAvG1ba2uq01x/LtcnDkpOj8=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/lmittmann/tint v1.1.1 h1:xmmGuinUsCSxWdwH1OqMUQ4tzQsq3BdjJLAAmVKJ9Dw=
+github.com/lmittmann/tint v1.1.1/go.mod h1:HIS3gSy7qNwGCj+5oRjAutErFBl4BzdQP6cJZ0NfMwE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/samber/lo v1.49.1 h1:4BIFyVfuQSEpluc7Fua+j1NolZHiEHEpaSEKdsH0tew=
+github.com/samber/lo v1.49.1/go.mod h1:dO6KHFzUKXgP8LDhU0oI8d2hekjXnGOu0DB8Jecxd6o=
+github.com/samber/slog-multi v1.4.0 h1:pwlPMIE7PrbTHQyKWDU+RIoxP1+HKTNOujk3/kdkbdg=
+github.com/samber/slog-multi v1.4.0/go.mod h1:FsQ4Uv2L+E/8TZt+/BVgYZ1LoDWCbfCU21wVIoMMrO8=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
+golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=