Add support for multiple output files in different formats (#732)

internal/output/writer.go

@@ -0,0 +1,116 @@
+package output
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path"
+
+	"github.com/anchore/syft/syft/format"
+	"github.com/anchore/syft/syft/sbom"
+	"github.com/hashicorp/go-multierror"
+)
+
+// streamWriter implements sbom.Writer for a given format and io.Writer, also providing a close function for cleanup
+type streamWriter struct {
+	format format.Format
+	out    io.Writer
+	close  func() error
+}
+
+// Write the provided SBOM to the data stream
+func (w *streamWriter) Write(s sbom.SBOM) error {
+	return w.format.Encode(w.out, s)
+}
+
+// Close any resources, such as open files
+func (w *streamWriter) Close() error {
+	if w.close != nil {
+		return w.close()
+	}
+	return nil
+}
+
+// multiWriter holds a list of child sbom.Writers to apply all Write and Close operations to
+type multiWriter struct {
+	writers []sbom.Writer
+}
+
+// Write writes the SBOM to all writers
+func (m *multiWriter) Write(s sbom.SBOM) (errs error) {
+	for _, w := range m.writers {
+		err := w.Write(s)
+		if err != nil {
+			errs = multierror.Append(errs, err)
+		}
+	}
+	return errs
+}
+
+// Close closes all writers
+func (m *multiWriter) Close() (errs error) {
+	for _, w := range m.writers {
+		err := w.Close()
+		if err != nil {
+			errs = multierror.Append(errs, err)
+		}
+	}
+	return errs
+}
+
+// WriterOption Format and path strings used to create sbom.Writer
+type WriterOption struct {
+	Format format.Format
+	Path   string
+}
+
+// MakeWriter create all report writers from input options; if a file is not specified, os.Stdout is used
+func MakeWriter(options ...WriterOption) (_ sbom.Writer, errs error) {
+	if len(options) == 0 {
+		return nil, fmt.Errorf("no output options provided")
+	}
+
+	out := &multiWriter{}
+
+	defer func() {
+		if errs != nil {
+			// close any previously opened files; we can't really recover from any errors
+			_ = out.Close()
+		}
+	}()
+
+	for _, option := range options {
+		switch len(option.Path) {
+		case 0:
+			out.writers = append(out.writers, &streamWriter{
+				format: option.Format,
+				out:    os.Stdout,
+			})
+		default:
+			// create any missing subdirectories
+			dir := path.Dir(option.Path)
+			if dir != "" {
+				s, err := os.Stat(dir)
+				if err != nil {
+					err = os.MkdirAll(dir, 0755) // maybe should be os.ModePerm ?
+					if err != nil {
+						return nil, err
+					}
+				} else if !s.IsDir() {
+					return nil, fmt.Errorf("output path does not contain a valid directory: %s", option.Path)
+				}
+			}
+			fileOut, err := os.OpenFile(option.Path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
+			if err != nil {
+				return nil, fmt.Errorf("unable to create report file: %w", err)
+			}
+			out.writers = append(out.writers, &streamWriter{
+				format: option.Format,
+				out:    fileOut,
+				close:  fileOut.Close,
+			})
+		}
+	}
+
+	return out, nil
+}

internal/output/writer_test.go

@@ -0,0 +1,168 @@
+package output
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/anchore/syft/internal/formats/spdx22json"
+	"github.com/anchore/syft/internal/formats/syftjson"
+	"github.com/anchore/syft/internal/formats/table"
+	"github.com/anchore/syft/internal/formats/text"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type writerConfig struct {
+	format string
+	file   string
+}
+
+func TestOutputWriter(t *testing.T) {
+	tmp := t.TempDir()
+
+	testName := func(options []WriterOption, err bool) string {
+		var out []string
+		for _, opt := range options {
+			out = append(out, string(opt.Format.Option)+"="+opt.Path)
+		}
+		errs := ""
+		if err {
+			errs = "(err)"
+		}
+		return strings.Join(out, ", ") + errs
+	}
+
+	tests := []struct {
+		outputs  []WriterOption
+		err      bool
+		expected []writerConfig
+	}{
+		{
+			outputs: []WriterOption{},
+			err:     true,
+		},
+		{
+			outputs: []WriterOption{
+				{
+					Format: table.Format(),
+					Path:   "",
+				},
+			},
+			expected: []writerConfig{
+				{
+					format: "table",
+				},
+			},
+		},
+		{
+			outputs: []WriterOption{
+				{
+					Format: syftjson.Format(),
+				},
+			},
+			expected: []writerConfig{
+				{
+					format: "json",
+				},
+			},
+		},
+		{
+			outputs: []WriterOption{
+				{
+					Format: syftjson.Format(),
+					Path:   "test-2.json",
+				},
+			},
+			expected: []writerConfig{
+				{
+					format: "json",
+					file:   "test-2.json",
+				},
+			},
+		},
+		{
+			outputs: []WriterOption{
+				{
+					Format: syftjson.Format(),
+					Path:   "test-3/1.json",
+				},
+				{
+					Format: spdx22json.Format(),
+					Path:   "test-3/2.json",
+				},
+			},
+			expected: []writerConfig{
+				{
+					format: "json",
+					file:   "test-3/1.json",
+				},
+				{
+					format: "spdx-json",
+					file:   "test-3/2.json",
+				},
+			},
+		},
+		{
+			outputs: []WriterOption{
+				{
+					Format: text.Format(),
+				},
+				{
+					Format: spdx22json.Format(),
+					Path:   "test-4.json",
+				},
+			},
+			expected: []writerConfig{
+				{
+					format: "text",
+				},
+				{
+					format: "spdx-json",
+					file:   "test-4.json",
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(testName(test.outputs, test.err), func(t *testing.T) {
+			outputs := test.outputs
+			for i := range outputs {
+				if outputs[i].Path != "" {
+					outputs[i].Path = tmp + outputs[i].Path
+				}
+			}
+
+			writer, err := MakeWriter(outputs...)
+
+			if test.err {
+				assert.Error(t, err)
+				return
+			} else {
+				assert.NoError(t, err)
+			}
+
+			mw := writer.(*multiWriter)
+
+			assert.Len(t, mw.writers, len(test.expected))
+
+			for i, e := range test.expected {
+				w := mw.writers[i].(*streamWriter)
+
+				assert.Equal(t, string(w.format.Option), e.format)
+
+				if e.file != "" {
+					assert.FileExists(t, tmp+e.file)
+				}
+
+				if e.file != "" {
+					assert.NotNil(t, w.out)
+					assert.NotNil(t, w.close)
+				} else {
+					assert.NotNil(t, w.out)
+					assert.Nil(t, w.close)
+				}
+			}
+		})
+	}
+}