feat(lib): configurable log file location (#2380)

## Description

Allows for Zarf's logs to still be sent to a log file, but be muted
otherwise.

```go
logFile, err := message.UseLogFile("")
if err != nil {
	return err // handle the error as you see fit
}

location := message.LogFileLocation() // get the log file location if you want to

// set pterm output to only go to this logfile
pterm.SetDefaultOutput(logFile)

// disable progress bars (otherwise they will still get printed to STDERR)
message.NoProgress = true
```

## Related Issue

Fixes #2372 

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Other (security config, docs update, etc)

## Checklist before merging

- [ ] Test, docs, adr added or updated as needed
- [x] [Contributor Guide
Steps](https://github.com/defenseunicorns/zarf/blob/main/CONTRIBUTING.md#developer-workflow)
followed

---------

Signed-off-by: razzle <[email protected]>

src/cmd/common/setup.go

@@ -5,11 +5,13 @@
 package common
 
 import (
+	"io"
 	"os"
 
 	"github.com/defenseunicorns/zarf/src/config"
 	"github.com/defenseunicorns/zarf/src/config/lang"
 	"github.com/defenseunicorns/zarf/src/pkg/message"
+	"github.com/pterm/pterm"
 )
 
 // LogLevelCLI holds the log level as input from a command
@@ -49,6 +51,14 @@ func SetupCLI() {
 	}
 
 	if !config.SkipLogFile {
-		message.UseLogFile()
+		logFile, err := message.UseLogFile("")
+		if err != nil {
+			message.WarnErr(err, "Error saving a log file to a temporary directory")
+			return
+		}
+
+		pterm.SetDefaultOutput(io.MultiWriter(os.Stderr, logFile))
+		location := message.LogFileLocation()
+		message.Notef("Saving log file to %s", location)
 	}
 }

src/pkg/message/credentials.go

@@ -6,7 +6,6 @@ package message
 
 import (
 	"fmt"
-	"os"
 	"strings"
 
 	"github.com/defenseunicorns/zarf/src/config"
@@ -31,8 +30,11 @@ func PrintCredentialTable(state *types.ZarfState, componentsToDeploy []types.Dep
 		componentsToDeploy = []types.DeployedComponent{{Name: "logging"}, {Name: "git-server"}}
 	}
 
-	// Set output to os.Stderr to avoid creds being printed in logs
-	pterm.SetDefaultOutput(os.Stderr)
+	// Pause the logfile's output to avoid credentials being printed to the log file
+	if logFile != nil {
+		logFile.pause()
+		defer logFile.resume()
+	}
 
 	loginData := [][]string{}
 	if state.RegistryInfo.InternalRegistry {
@@ -61,11 +63,6 @@ func PrintCredentialTable(state *types.ZarfState, componentsToDeploy []types.Dep
 		header := []string{"Application", "Username", "Password", "Connect", "Get-Creds Key"}
 		Table(header, loginData)
 	}
-
-	// Restore the log file if it was specified
-	if !config.SkipLogFile {
-		UseLogFile()
-	}
 }
 
 // PrintComponentCredential displays credentials for a single component
@@ -96,8 +93,11 @@ func PrintComponentCredential(state *types.ZarfState, componentName string) {
 
 // PrintCredentialUpdates displays credentials that will be updated
 func PrintCredentialUpdates(oldState *types.ZarfState, newState *types.ZarfState, services []string) {
-	// Set output to os.Stderr to avoid creds being printed in logs
-	pterm.SetDefaultOutput(os.Stderr)
+	// Pause the logfile's output to avoid credentials being printed to the log file
+	if logFile != nil {
+		logFile.pause()
+		defer logFile.resume()
+	}
 
 	for _, service := range services {
 
@@ -144,11 +144,6 @@ func PrintCredentialUpdates(oldState *types.ZarfState, newState *types.ZarfState
 	}
 
 	pterm.Println()
-
-	// Restore the log file if it was specified
-	if !config.SkipLogFile {
-		UseLogFile()
-	}
 }
 
 func compareStrings(old string, new string, secret bool) string {

src/pkg/message/message.go

@@ -44,17 +44,11 @@ var NoProgress bool
 // RuleLine creates a line of ━ as wide as the terminal
 var RuleLine = strings.Repeat("━", TermWidth)
 
-// LogWriter is the stream to write logs to.
-var LogWriter io.Writer = os.Stderr
-
 // logLevel holds the pterm compatible log level integer
 var logLevel = InfoLevel
 
 // logFile acts as a buffer for logFile generation
-var logFile *os.File
-
-// useLogFile controls whether to use the log file or not
-var useLogFile bool
+var logFile *pausableLogFile
 
 // DebugWriter represents a writer interface that writes to message.Debug
 type DebugWriter struct{}
@@ -83,27 +77,29 @@ func init() {
 }
 
 // UseLogFile writes output to stderr and a logFile.
-func UseLogFile() {
+func UseLogFile(dir string) (io.Writer, error) {
 	// Prepend the log filename with a timestamp.
 	ts := time.Now().Format("2006-01-02-15-04-05")
 
-	var err error
-	if logFile != nil {
-		// Use the existing log file if logFile is set
-		LogWriter = io.MultiWriter(os.Stderr, logFile)
-		pterm.SetDefaultOutput(LogWriter)
-	} else {
-		// Try to create a temp log file if one hasn't been made already
-		if logFile, err = os.CreateTemp("", fmt.Sprintf("zarf-%s-*.log", ts)); err != nil {
-			WarnErr(err, "Error saving a log file to a temporary directory")
-		} else {
-			useLogFile = true
-			LogWriter = io.MultiWriter(os.Stderr, logFile)
-			pterm.SetDefaultOutput(LogWriter)
-			message := fmt.Sprintf("Saving log file to %s", logFile.Name())
-			Note(message)
-		}
+	f, err := os.CreateTemp(dir, fmt.Sprintf("zarf-%s-*.log", ts))
+	if err != nil {
+		return nil, err
+	}
+
+	logFile = &pausableLogFile{
+		wr: f,
+		f:  f,
 	}
+
+	return logFile, nil
+}
+
+// LogFileLocation returns the location of the log file.
+func LogFileLocation() string {
+	if logFile == nil {
+		return ""
+	}
+	return logFile.f.Name()
 }
 
 // SetLogLevel sets the log level.
@@ -223,8 +219,8 @@ func Question(text string) {
 
 // Questionf prints a user prompt description message with a given format.
 func Questionf(format string, a ...any) {
-	pterm.Println()
 	message := Paragraph(format, a...)
+	pterm.Println()
 	pterm.FgLightGreen.Println(message)
 }
 
@@ -235,7 +231,6 @@ func Note(text string) {
 
 // Notef prints a note message  with a given format.
 func Notef(format string, a ...any) {
-	pterm.Println()
 	message := Paragraphn(TermWidth-7, format, a...)
 	notePrefix := pterm.PrefixPrinter{
 		MessageStyle: &pterm.ThemeDefault.InfoMessageStyle,
@@ -244,6 +239,7 @@ func Notef(format string, a ...any) {
 			Text:  "NOTE",
 		},
 	}
+	pterm.Println()
 	notePrefix.Println(message)
 }
 
@@ -256,10 +252,10 @@ func Title(title string, help string) {
 
 // HeaderInfof prints a large header with a formatted message.
 func HeaderInfof(format string, a ...any) {
+	pterm.Println()
 	message := Truncate(fmt.Sprintf(format, a...), TermWidth, false)
 	// Ensure the text is consistent for the header width
 	padding := TermWidth - len(message)
-	pterm.Println()
 	pterm.DefaultHeader.
 		WithBackgroundStyle(pterm.NewStyle(pterm.BgDarkGray)).
 		WithTextStyle(pterm.NewStyle(pterm.FgLightWhite)).
@@ -366,7 +362,7 @@ func debugPrinter(offset int, a ...any) {
 	printer.Println(a...)
 
 	// Always write to the log file
-	if useLogFile {
+	if logFile != nil {
 		pterm.Debug.
 			WithShowLineNumber(true).
 			WithLineNumberOffset(offset).

src/pkg/message/pausable.go

@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: 2021-Present The Zarf Authors
+
+// Package message provides a rich set of functions for displaying messages to the user.
+package message
+
+import (
+	"io"
+	"os"
+)
+
+// pausableLogFile is a pausable log file
+type pausableLogFile struct {
+	wr io.Writer
+	f  *os.File
+}
+
+// pause the log file
+func (l *pausableLogFile) pause() {
+	l.wr = io.Discard
+}
+
+// resume the log file
+func (l *pausableLogFile) resume() {
+	l.wr = l.f
+}
+
+// Write writes the data to the log file
+func (l *pausableLogFile) Write(p []byte) (n int, err error) {
+	return l.wr.Write(p)
+}

src/pkg/message/progress.go

@@ -5,6 +5,8 @@
 package message
 
 import (
+	"os"
+
 	"github.com/pterm/pterm"
 )
 
@@ -28,6 +30,7 @@ func NewProgressBar(total int64, text string) *ProgressBar {
 			WithTitle(padding + text).
 			WithRemoveWhenDone(true).
 			WithMaxWidth(TermWidth).
+			WithWriter(os.Stderr).
 			Start()
 	}