feat: add --ignore option (#46)

* Add --ignore option

Packages beginning with the specified path will be ignored.
Imported packages by ignored packages are still checked.

* Use pflag.StringSlice instead of custom type

* Fix option description

* Clarify dependencies from the ignored packages are still checked

* Add README section

Co-authored-by: Yuan (Bob) Gong <[email protected]>

Author: at-wat

README.md

@@ -166,6 +166,20 @@ github.com/client9/misspell,https://github.com/client9/misspell/blob/master/LICE
 github.com/golang/protobuf/proto,https://github.com/golang/protobuf/blob/master/proto/LICENSE,BSD-3-Clause
 ```
 
+## Ignoring packages
+
+Use the `--ignore` global flag to specify package path prefixes to be ignored.
+For example, to ignore your organization's internal packages under `github.com/example-corporation`:
+
+```shell
+$ go-licenses check \
+    github.com/example-corporation/example-product \
+    --ignore github.com/example-corporation
+```
+
+Note that dependencies from the ignored packages are still resolved and checked.
+This flag makes effect to `check`, `csv` and `save` commands.
+
 ## Warnings and errors
 
 The tool will log warnings and errors in some scenarios. This section provides

check.go

@@ -44,7 +44,7 @@ func checkMain(_ *cobra.Command, args []string) error {
 		return err
 	}
 
-	libs, err := licenses.Libraries(context.Background(), classifier, args...)
+	libs, err := licenses.Libraries(context.Background(), classifier, ignore, args...)
 	if err != nil {
 		return err
 	}

csv.go

@@ -51,7 +51,7 @@ func csvMain(_ *cobra.Command, args []string) error {
 		return err
 	}
 
-	libs, err := licenses.Libraries(context.Background(), classifier, args...)
+	libs, err := licenses.Libraries(context.Background(), classifier, ignore, args...)
 	if err != nil {
 		return err
 	}

licenses/library.go

@@ -59,7 +59,7 @@ func (e PackagesError) Error() string {
 // A library is a collection of one or more packages covered by the same license file.
 // Packages not covered by a license will be returned as individual libraries.
 // Standard library packages will be ignored.
-func Libraries(ctx context.Context, classifier Classifier, importPaths ...string) ([]*Library, error) {
+func Libraries(ctx context.Context, classifier Classifier, ignoredPaths []string, importPaths ...string) ([]*Library, error) {
 	cfg := &packages.Config{
 		Context: ctx,
 		Mode:    packages.NeedImports | packages.NeedDeps | packages.NeedFiles | packages.NeedName | packages.NeedModule,
@@ -83,6 +83,13 @@ func Libraries(ctx context.Context, classifier Classifier, importPaths ...string
 			// No license requirements for the Go standard library.
 			return false
 		}
+		for _, i := range ignoredPaths {
+			if strings.HasPrefix(p.PkgPath, i) {
+				// Marked to be ignored.
+				return true
+			}
+		}
+
 		if len(p.OtherFiles) > 0 {
 			glog.Warningf("%q contains non-Go code that can't be inspected for further dependencies:\n%s", p.PkgPath, strings.Join(p.OtherFiles, "\n"))
 		}

licenses/library_test.go

@@ -41,6 +41,7 @@ func TestLibraries(t *testing.T) {
 		desc       string
 		importPath string
 		goflags    string
+		ignore     []string
 		wantLibs   []string
 	}{
 		{
@@ -60,6 +61,17 @@ func TestLibraries(t *testing.T) {
 				"github.com/google/go-licenses/licenses/testdata/indirect",
 			},
 		},
+		{
+			desc:       "Ignores a package path",
+			importPath: "github.com/google/go-licenses/licenses/testdata",
+			ignore: []string{
+				"github.com/google/go-licenses/licenses/testdata/direct",
+			},
+			wantLibs: []string{
+				"github.com/google/go-licenses/licenses/testdata",
+				"github.com/google/go-licenses/licenses/testdata/indirect",
+			},
+		},
 		{
 			desc:       "Build tagged package",
 			importPath: "github.com/google/go-licenses/licenses/testdata/tags",
@@ -75,7 +87,7 @@ func TestLibraries(t *testing.T) {
 				os.Setenv("GOFLAGS", test.goflags)
 				defer os.Unsetenv("GOFLAGS")
 			}
-			gotLibs, err := Libraries(context.Background(), classifier, test.importPath)
+			gotLibs, err := Libraries(context.Background(), classifier, test.ignore, test.importPath)
 			if err != nil {
 				t.Fatalf("Libraries(_, %q) = (_, %q), want (_, nil)", test.importPath, err)
 			}

main.go

@@ -38,6 +38,7 @@ Prerequisites:
 
 	// Flags shared between subcommands
 	confidenceThreshold float64
+	ignore              []string
 	packageHelp         = `
 
 Typically, specify the Go package that builds your Go binary.
@@ -63,6 +64,7 @@ func init() {
 		os.Exit(1)
 	}
 	rootCmd.PersistentFlags().Float64Var(&confidenceThreshold, "confidence_threshold", 0.9, "Minimum confidence required in order to positively identify a license.")
+	rootCmd.PersistentFlags().StringSliceVar(&ignore, "ignore", nil, "Package path prefixes to be ignored. Dependencies from the ignored packages are still checked. Can be specified multiple times.")
 }
 
 func main() {

save.go

@@ -75,7 +75,7 @@ func saveMain(_ *cobra.Command, args []string) error {
 		return err
 	}
 
-	libs, err := licenses.Libraries(context.Background(), classifier, args...)
+	libs, err := licenses.Libraries(context.Background(), classifier, ignore, args...)
 	if err != nil {
 		return err
 	}