Add option to output SBOM report to a file (#530)

* add output to file option

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* log errors on close of the report destination

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* remove file option from persistent args

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* update file option comments and logging

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* allow for multiple UI fallback options

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* update UI select signatures + tests

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

internal/ui/ephemeral_terminal_ui.go

@@ -33,25 +33,28 @@ import (
 // or in the shared ui package as a function on the main handler object. All handler functions should be completed
 // processing an event before the ETUI exits (coordinated with a sync.WaitGroup)
 type ephemeralTerminalUI struct {
-	unsubscribe func() error
-	handler     *ui.Handler
-	waitGroup   *sync.WaitGroup
-	frame       *frame.Frame
-	logBuffer   *bytes.Buffer
-	output      *os.File
+	unsubscribe  func() error
+	handler      *ui.Handler
+	waitGroup    *sync.WaitGroup
+	frame        *frame.Frame
+	logBuffer    *bytes.Buffer
+	uiOutput     *os.File
+	reportOutput io.Writer
 }
 
-func NewEphemeralTerminalUI() UI {
+// NewEphemeralTerminalUI writes all events to a TUI and writes the final report to the given writer.
+func NewEphemeralTerminalUI(reportWriter io.Writer) UI {
 	return &ephemeralTerminalUI{
-		handler:   ui.NewHandler(),
-		waitGroup: &sync.WaitGroup{},
-		output:    os.Stderr,
+		handler:      ui.NewHandler(),
+		waitGroup:    &sync.WaitGroup{},
+		uiOutput:     os.Stderr,
+		reportOutput: reportWriter,
 	}
 }
 
 func (h *ephemeralTerminalUI) Setup(unsubscribe func() error) error {
 	h.unsubscribe = unsubscribe
-	hideCursor(h.output)
+	hideCursor(h.uiOutput)
 
 	// prep the logger to not clobber the screen from now on (logrus only)
 	h.logBuffer = bytes.NewBufferString("")
@@ -81,7 +84,7 @@ func (h *ephemeralTerminalUI) Handle(event partybus.Event) error {
 		// are about to write bytes to stdout, so we should reset the terminal state first
 		h.closeScreen(false)
 
-		if err := handleCatalogerPresenterReady(event); err != nil {
+		if err := handleCatalogerPresenterReady(event, h.reportOutput); err != nil {
 			log.Errorf("unable to show %s event: %+v", event.Type, err)
 		}
 
@@ -95,7 +98,7 @@ func (h *ephemeralTerminalUI) openScreen() error {
 	config := frame.Config{
 		PositionPolicy: frame.PolicyFloatForward,
 		// only report output to stderr, reserve report output for stdout
-		Output: h.output,
+		Output: h.uiOutput,
 	}
 
 	fr, err := frame.New(config)
@@ -128,15 +131,15 @@ func (h *ephemeralTerminalUI) flushLog() {
 	logWrapper, ok := log.Log.(*logger.LogrusLogger)
 	if ok {
 		fmt.Fprint(logWrapper.Output, h.logBuffer.String())
-		logWrapper.Logger.SetOutput(h.output)
+		logWrapper.Logger.SetOutput(h.uiOutput)
 	} else {
-		fmt.Fprint(h.output, h.logBuffer.String())
+		fmt.Fprint(h.uiOutput, h.logBuffer.String())
 	}
 }
 
 func (h *ephemeralTerminalUI) Teardown(force bool) error {
 	h.closeScreen(force)
-	showCursor(h.output)
+	showCursor(h.uiOutput)
 	return nil
 }
 

internal/ui/event_handlers.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"os"
 	"sync"
 
 	"github.com/anchore/syft/internal"
@@ -17,14 +16,14 @@ import (
 
 // handleCatalogerPresenterReady is a UI function for processing the CatalogerFinished bus event, displaying the catalog
 // via the given presenter to stdout.
-func handleCatalogerPresenterReady(event partybus.Event) error {
+func handleCatalogerPresenterReady(event partybus.Event, reportOutput io.Writer) error {
 	// show the report to stdout
 	pres, err := syftEventParsers.ParsePresenterReady(event)
 	if err != nil {
 		return fmt.Errorf("bad CatalogerFinished event: %w", err)
 	}
 
-	if err := pres.Present(os.Stdout); err != nil {
+	if err := pres.Present(reportOutput); err != nil {
 		return fmt.Errorf("unable to show package catalog report: %w", err)
 	}
 	return nil

internal/ui/logger_ui.go

@@ -1,17 +1,23 @@
 package ui
 
 import (
+	"io"
+
 	"github.com/anchore/syft/internal/log"
 	syftEvent "github.com/anchore/syft/syft/event"
 	"github.com/wagoodman/go-partybus"
 )
 
 type loggerUI struct {
-	unsubscribe func() error
+	unsubscribe  func() error
+	reportOutput io.Writer
 }
 
-func NewLoggerUI() UI {
-	return &loggerUI{}
+// NewLoggerUI writes all events to the common application logger and writes the final report to the given writer.
+func NewLoggerUI(reportWriter io.Writer) UI {
+	return &loggerUI{
+		reportOutput: reportWriter,
+	}
 }
 
 func (l *loggerUI) Setup(unsubscribe func() error) error {
@@ -25,7 +31,7 @@ func (l loggerUI) Handle(event partybus.Event) error {
 		return nil
 	}
 
-	if err := handleCatalogerPresenterReady(event); err != nil {
+	if err := handleCatalogerPresenterReady(event, l.reportOutput); err != nil {
 		log.Warnf("unable to show catalog image finished event: %+v", err)
 	}
 

internal/ui/select.go

@@ -1,6 +1,7 @@
 package ui
 
 import (
+	"io"
 	"os"
 	"runtime"
 
@@ -10,20 +11,21 @@ import (
 // TODO: build tags to exclude options from windows
 
 // Select is responsible for determining the specific UI function given select user option, the current platform
-// config values, and environment status (such as a TTY being present).
-func Select(verbose, quiet bool) UI {
-	var ui UI
-
+// config values, and environment status (such as a TTY being present). The first UI in the returned slice of UIs
+// is intended to be used and the UIs that follow are meant to be attempted only in a fallback posture when there
+// are environmental problems (e.g. cannot write to the terminal). A writer is provided to capture the output of
+// the final SBOM report.
+func Select(verbose, quiet bool, reportWriter io.Writer) (uis []UI) {
 	isStdoutATty := terminal.IsTerminal(int(os.Stdout.Fd()))
 	isStderrATty := terminal.IsTerminal(int(os.Stderr.Fd()))
 	notATerminal := !isStderrATty && !isStdoutATty
 
 	switch {
 	case runtime.GOOS == "windows" || verbose || quiet || notATerminal || !isStderrATty:
-		ui = NewLoggerUI()
+		uis = append(uis, NewLoggerUI(reportWriter))
 	default:
-		ui = NewEphemeralTerminalUI()
+		uis = append(uis, NewEphemeralTerminalUI(reportWriter), NewLoggerUI(reportWriter))
 	}
 
-	return ui
+	return uis
 }