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Author SHA1 Message Date
end 164f5bea34 chore: pin app dependency and add local replace for workspace
Co-authored-by: Cursor <cursoragent@cursor.com>
2026-06-29 18:04:25 -07:00
end 626e1bb5ac fix: lifecycle-safe logger teardown without global state
Store file handle per module, swap lifecycle logger before closing file,
return teardown errors, remove duplicate Module() func.

Co-authored-by: Cursor <cursoragent@cursor.com>
2026-06-29 18:01:08 -07:00
9 changed files with 260 additions and 149 deletions
+3
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@@ -0,0 +1,3 @@
coverage.out
coverage.html
*.test
+37 -2
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@@ -1,5 +1,40 @@
# applog
applog is a opinionated logger configuration.
Opinionated slog wiring for go-toolkit [app](https://gitea.auvem.com/go-toolkit/app) lifecycles.
WARNING: do not use this library, the API is not stable and I make breaking changes at random. There's a reason it's not on GitHub yet, or possibly ever tbh.
## Install
```bash
go get gitea.auvem.com/go-toolkit/applog
```
## Usage
```go
lifecycle := app.NewLifecycle(applog.AppLogOpts{
ConsoleOutput: os.Stderr,
ConsoleLevel: slog.LevelInfo,
FileOutput: "/var/log/myapp.log",
FileLevel: slog.LevelInfo,
}.Module())
```
## Outputs
| Sink | Format | Default level |
|------|--------|---------------|
| Console (`ConsoleOutput`) | tint (human-readable) | Info |
| File (`FileOutput`) | JSON lines | Info |
## Teardown
On teardown the log file is closed and the lifecycle logger falls back to console-only (or discard). Logging via `lifecycle.Logger()` after teardown does not write to a closed file.
## Migration from pre-V1 API
| Before | After |
|--------|-------|
| `applog.Module(opts)` | `opts.Module()` |
| `LogOutput` | `ConsoleOutput` |
| `LogFile` | `FileOutput` |
| `Verbose bool` | `ConsoleLevel: slog.LevelDebug` |
-146
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@@ -1,146 +0,0 @@
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 {
// ConsoleOutput is the writer for pretty-printed console logs. If nil,
// console output is disabled. Generally recommended to set this to
// os.Stderr, leaving os.Stdout for application output (usually via
// fmt.Print*).
ConsoleOutput io.Writer
// ConsoleLevel is the minimum log level for console output. Defaults to
// slog.LevelInfo.
ConsoleLevel slog.Level
// FileOutput is the path to a file where JSON formatted logs will be
// written. If empty, file output will be disabled.
FileOutput string
// FileLevel is the minimum log level for file output. Defaults to
// slog.LevelInfo.
FileLevel slog.Level
// SetDefault indicates whether to set the logger as the default logger
// for slog. Generally recommended to manage logger via app lifecycle
// instead of relying on globals.
SetDefault bool
// Disables announcement of log module w/ log level on app start.
DisableAnnouncement 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.FileOutput == "" && opts.ConsoleOutput == nil {
return fmt.Errorf("no logging output configured")
}
if err := setupLogger(m.Lifecycle(), opts); err != nil {
return fmt.Errorf("failed to set up logger: %w", err)
}
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, opts AppLogOpts) error {
handlers := make([]slog.Handler, 0)
// If log file is specified, set up JSON file logging
if opts.FileOutput != "" {
var err error
logfile, err = os.OpenFile(opts.FileOutput, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
if err != nil {
return err
}
fileHandler := slog.NewJSONHandler(logfile, &slog.HandlerOptions{
Level: opts.FileLevel,
})
if !opts.DisableAnnouncement {
slog.New(fileHandler).Info("Logger initialized", "level", opts.FileLevel.String(), "output", opts.FileOutput)
}
handlers = append(handlers, fileHandler)
}
// If log output is specified, set up pretty-printed console logging
if opts.ConsoleOutput != nil {
consoleHandler := tint.NewHandler(opts.ConsoleOutput, &tint.Options{
Level: opts.ConsoleLevel,
TimeFormat: time.Kitchen,
})
if !opts.DisableAnnouncement {
slog.New(consoleHandler).Info("Logger initialized", "level", opts.ConsoleLevel.String())
}
handlers = append(handlers, consoleHandler)
}
logger := slog.New(slogmulti.Fanout(handlers...))
lifecycle.WithLogger(logger) // set logger on lifecycle
// optionally set logger as slog default (not recommended)
if opts.SetDefault {
slog.SetDefault(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)
}
}
+57
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@@ -0,0 +1,57 @@
package applog_test
import (
"bytes"
"io"
"log/slog"
"os"
"path/filepath"
"testing"
"gitea.auvem.com/go-toolkit/applog"
"gitea.auvem.com/go-toolkit/app"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
func TestModuleConsoleOnly(t *testing.T) {
var buf bytes.Buffer
lc := app.NewLifecycle(applog.AppLogOpts{
ConsoleOutput: &buf,
ConsoleLevel: slog.LevelDebug,
DisableAnnouncement: true,
}.Module())
require.NoError(t, lc.Setup())
lc.Logger().Info("hello")
require.NoError(t, lc.Teardown())
assert.Contains(t, buf.String(), "hello")
}
func TestModuleRequiresOutput(t *testing.T) {
lc := app.NewLifecycle(applog.AppLogOpts{}.Module())
err := lc.Setup()
assert.Error(t, err)
}
func TestModuleFileAndTeardown(t *testing.T) {
dir := t.TempDir()
logPath := filepath.Join(dir, "app.log")
lc := app.NewLifecycle(applog.AppLogOpts{
ConsoleOutput: io.Discard,
FileOutput: logPath,
DisableAnnouncement: true,
}.Module())
require.NoError(t, lc.Setup())
lc.Logger().Info("file line")
require.NoError(t, lc.Teardown())
// Logger should not write to closed file after teardown
lc.Logger().Info("after teardown")
data, err := os.ReadFile(logPath)
require.NoError(t, err)
assert.Contains(t, string(data), "file line")
}
+6
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@@ -0,0 +1,6 @@
// Package applog configures slog for [gitea.auvem.com/go-toolkit/app.Lifecycle]
// with optional JSON file output and tint console formatting.
//
// Teardown closes the log file and re-points the lifecycle logger to console-only
// (or discard if console is disabled) so post-teardown lifecycle logs remain safe.
package applog
+7 -1
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@@ -3,12 +3,18 @@ module gitea.auvem.com/go-toolkit/applog
go 1.24.0
require (
gitea.auvem.com/go-toolkit/app v0.0.0-20250603235859-6f9e3731acf9
gitea.auvem.com/go-toolkit/app v0.0.0-1782781086-58e5e33e18da
github.com/lmittmann/tint v1.1.1
github.com/samber/slog-multi v1.4.0
github.com/stretchr/testify v1.10.0
)
require (
github.com/davecgh/go-spew v1.1.1 // indirect
github.com/pmezard/go-difflib v1.0.0 // indirect
github.com/samber/lo v1.49.1 // indirect
golang.org/x/text v0.25.0 // indirect
gopkg.in/yaml.v3 v3.0.1 // indirect
)
replace gitea.auvem.com/go-toolkit/app => ../app
+8
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@@ -2,8 +2,12 @@ gitea.auvem.com/go-toolkit/app v0.0.0-20250603235859-6f9e3731acf9 h1:MYOI+bB4IBA
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/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
github.com/lmittmann/tint v1.1.1 h1:xmmGuinUsCSxWdwH1OqMUQ4tzQsq3BdjJLAAmVKJ9Dw=
github.com/lmittmann/tint v1.1.1/go.mod h1:HIS3gSy7qNwGCj+5oRjAutErFBl4BzdQP6cJZ0NfMwE=
github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
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=
@@ -13,5 +17,9 @@ github.com/samber/slog-multi v1.4.0/go.mod h1:FsQ4Uv2L+E/8TZt+/BVgYZ1LoDWCbfCU21
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 v0.25.0 h1:qVyWApTSYLk/drJRO5mDlNYskwQznZmkpV2c8q9zls4=
golang.org/x/text v0.25.0/go.mod h1:WEdwpYrmk1qmdHvhkSTNPm3app7v4rsT8F2UD6+VHIA=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU=
gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+51
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@@ -0,0 +1,51 @@
package applog
import (
"io"
"log/slog"
"gitea.auvem.com/go-toolkit/app"
)
// ModuleName is the name of the module provided by applog.
const ModuleName = "app logger"
// AppLogOpts contains options for configuring the application logger.
type AppLogOpts struct {
// ConsoleOutput is the writer for pretty-printed console logs. If nil,
// console output is disabled. Generally recommended to set this to
// os.Stderr, leaving os.Stdout for application output (usually via
// fmt.Print*).
ConsoleOutput io.Writer
// ConsoleLevel is the minimum log level for console output. Defaults to
// slog.LevelInfo when console output is enabled.
ConsoleLevel slog.Level
// FileOutput is the path to a file where JSON formatted logs will be
// written. If empty, file output is disabled.
FileOutput string
// FileLevel is the minimum log level for file output. Defaults to
// slog.LevelInfo when file output is enabled.
FileLevel slog.Level
// SetDefault sets slog.SetDefault to the configured logger.
SetDefault bool
// DisableAnnouncement skips the startup log line after initialization.
DisableAnnouncement bool
}
// Module returns an app module that configures slog for the lifecycle.
func (opts AppLogOpts) Module() *app.Module {
state := &moduleState{opts: opts}
return app.NewModule(ModuleName, app.ModuleOpts{
Setup: func(m *app.Module) error {
return state.setup(m)
},
Teardown: func(m *app.Module) error {
return state.teardown(m.Lifecycle())
},
})
}
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package applog
import (
"errors"
"fmt"
"log/slog"
"os"
"time"
"gitea.auvem.com/go-toolkit/app"
"github.com/lmittmann/tint"
slogmulti "github.com/samber/slog-multi"
)
type moduleState struct {
opts AppLogOpts
logfile *os.File
consoleHandler slog.Handler
}
func (s *moduleState) setup(m *app.Module) error {
if s.opts.FileOutput == "" && s.opts.ConsoleOutput == nil {
return fmt.Errorf("no logging output configured")
}
handlers := make([]slog.Handler, 0, 2)
if s.opts.FileOutput != "" {
f, err := os.OpenFile(s.opts.FileOutput, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
if err != nil {
return err
}
s.logfile = f
fileLevel := s.opts.FileLevel
if fileLevel == 0 && s.opts.ConsoleOutput == nil {
fileLevel = slog.LevelInfo
}
handlers = append(handlers, slog.NewJSONHandler(f, &slog.HandlerOptions{Level: fileLevel}))
}
if s.opts.ConsoleOutput != nil {
consoleLevel := s.opts.ConsoleLevel
if consoleLevel == 0 {
consoleLevel = slog.LevelInfo
}
s.consoleHandler = tint.NewHandler(s.opts.ConsoleOutput, &tint.Options{
Level: consoleLevel,
TimeFormat: time.Kitchen,
})
handlers = append(handlers, s.consoleHandler)
}
logger := slog.New(slogmulti.Fanout(handlers...))
m.Lifecycle().WithLogger(logger)
if s.opts.SetDefault {
slog.SetDefault(logger)
}
if !s.opts.DisableAnnouncement {
logger.Info("Logger initialized", "module", ModuleName)
}
return nil
}
func (s *moduleState) teardown(lifecycle *app.Lifecycle) error {
if lifecycle != nil {
switch {
case s.consoleHandler != nil:
lifecycle.WithLogger(slog.New(s.consoleHandler))
default:
lifecycle.WithLogger(slog.New(slog.DiscardHandler))
}
}
if s.logfile == nil {
return nil
}
var err error
if syncErr := s.logfile.Sync(); syncErr != nil {
err = fmt.Errorf("flush log file: %w", syncErr)
}
if closeErr := s.logfile.Close(); closeErr != nil {
err = errors.Join(err, fmt.Errorf("close log file: %w", closeErr))
}
s.logfile = nil
return err
}