feat: allow for stdout to be buffered on each command (#2335)

* feat: add preRun func to version to restore stdout

Signed-off-by: Christopher Phillips <christopher.phillips@anchore.com>

* test: add test to capture version in output

Signed-off-by: Christopher Phillips <christopher.phillips@anchore.com>

* change stdout buffering to log to be opt-in per command

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* fix tests

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

---------

Signed-off-by: Christopher Phillips <christopher.phillips@anchore.com>
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
Co-authored-by: Alex Goodman <wagoodman@users.noreply.github.com>

cmd/syft/internal/ui/capture.go

@@ -8,13 +8,19 @@ import (
 	"github.com/anchore/syft/internal/log"
 )
 
-// capture replaces the provided *os.File and redirects output to the provided writer. The return value is a function,
-// which is used to stop the current capturing of output and restore the original file.
+const defaultStdoutLogBufferSize = 1024
+
+// CaptureStdoutToTraceLog replaces stdout and redirects output to the log as trace lines. The return value is a
+// function, which is used to stop the current capturing of output and restore the original file.
 // Example:
 //
-//	restore := capture(&os.Stderr, writer)
-//	// here, stderr will be captured and redirected to the provided writer
-//	restore() // block until the output has all been sent to the writer and restore the original stderr
+//	restore := CaptureStdoutToTraceLog()
+//	// here, stdout will be captured and redirected to the provided writer
+//	restore() // block until the output has all been sent to the writer and restore the original stdout
+func CaptureStdoutToTraceLog() (close func()) {
+	return capture(&os.Stdout, newLogWriter(), defaultStdoutLogBufferSize)
+}
+
 func capture(target **os.File, writer io.Writer, bufSize int) (close func()) {
 	original := *target
 

cmd/syft/internal/ui/log_writer.go

@@ -25,7 +25,7 @@ func (l *logWriter) Write(data []byte) (n int, err error) {
 	s, err := l.r.ReadString('\n')
 	s = strings.TrimRight(s, "\n")
 	for s != "" {
-		log.Trace(s)
+		log.Trace("[unexpected stdout] " + s)
 		n += len(s)
 		if err != nil {
 			break

cmd/syft/internal/ui/log_writer_test.go

@@ -23,14 +23,14 @@ func Test_logWriter(t *testing.T) {
 
 	_, _ = w.Write([]byte("a\nvalue"))
 
-	expected := []any{"a", "value"}
+	expected := []any{"[unexpected stdout] a", "[unexpected stdout] value"}
 	require.Equal(t, expected, bl.values)
 
 	bl.values = nil
 	_, _ = w.Write([]byte("some"))
 	_, _ = w.Write([]byte("thing"))
 
-	expected = []any{"some", "thing"}
+	expected = []any{"[unexpected stdout] some", "[unexpected stdout] thing"}
 	require.Equal(t, expected, bl.values)
 }
 

cmd/syft/internal/ui/stdout_logging_application.go

@@ -1,63 +0,0 @@
-package ui
-
-import (
-	"os"
-
-	"github.com/spf13/cobra"
-	"github.com/spf13/pflag"
-
-	"github.com/anchore/clio"
-)
-
-const defaultStdoutLogBufferSize = 1024
-
-// StdoutLoggingApplication wraps the provided app in a clio.Application, which captures non-report data
-// written to os.Stdout and instead logs it to the internal logger. It also modifies the rootCmd help function
-// to restore os.Stdout in order for Cobra to properly print help to stdout
-func StdoutLoggingApplication(app clio.Application, rootCmd *cobra.Command) clio.Application {
-	return &stdoutLoggingApplication{
-		delegate: app,
-		rootCmd:  rootCmd,
-	}
-}
-
-// stdoutLoggingApplication is a clio.Application, which captures data written to os.Stdout prior to the report
-// being output and instead sends non-report output to the internal logger
-type stdoutLoggingApplication struct {
-	delegate clio.Application
-	rootCmd  *cobra.Command
-}
-
-func (s *stdoutLoggingApplication) ID() clio.Identification {
-	return s.delegate.ID()
-}
-
-func (s *stdoutLoggingApplication) AddFlags(flags *pflag.FlagSet, cfgs ...any) {
-	s.delegate.AddFlags(flags, cfgs...)
-}
-
-func (s *stdoutLoggingApplication) SetupCommand(cmd *cobra.Command, cfgs ...any) *cobra.Command {
-	return s.delegate.SetupCommand(cmd, cfgs...)
-}
-
-func (s *stdoutLoggingApplication) SetupRootCommand(cmd *cobra.Command, cfgs ...any) *cobra.Command {
-	return s.delegate.SetupRootCommand(cmd, cfgs...)
-}
-
-func (s *stdoutLoggingApplication) Run() {
-	// capture everything written to stdout that is not report output
-	restoreStdout := capture(&os.Stdout, newLogWriter(), defaultStdoutLogBufferSize)
-	defer restoreStdout()
-
-	// need to restore stdout for cobra to properly output help text to the user on stdout
-	baseHelpFunc := s.rootCmd.HelpFunc()
-	defer s.rootCmd.SetHelpFunc(baseHelpFunc)
-	s.rootCmd.SetHelpFunc(func(command *cobra.Command, strings []string) {
-		restoreStdout()
-		baseHelpFunc(command, strings)
-	})
-
-	s.delegate.Run()
-}
-
-var _ clio.Application = (*stdoutLoggingApplication)(nil)