Add support for indexing root filesystem (#442)

* change directory resolver to ignore system runtime paths + drive by index

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

* add event/etui support for filesystem indexing (for dir resolver)

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

* add warnings for path indexing problems

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

* add directory resolver index tests

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

* improve testing around directory resolver

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

* renamed p var to path when not conflicting with import

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

* pull docker image in CLI dir scan timeout test

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

* ensure file not exist errors do not stop directory resolver indexing

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

internal/string_helpers.go

@@ -12,3 +12,10 @@ func HasAnyOfPrefixes(input string, prefixes ...string) bool {
 
 	return false
 }
+
+func TruncateMiddleEllipsis(input string, maxLen int) string {
+	if len(input) <= maxLen {
+		return input
+	}
+	return input[:maxLen/2] + "..." + input[len(input)-(maxLen/2):]
+}

internal/string_helpers_test.go

@@ -1,6 +1,7 @@
 package internal
 
 import (
+	"strconv"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -63,3 +64,43 @@ func TestHasAnyOfPrefixes(t *testing.T) {
 		})
 	}
 }
+
+func TestTruncateMiddleEllipsis(t *testing.T) {
+	tests := []struct {
+		input    string
+		len      int
+		expected string
+	}{
+		{
+			input:    "nobody expects the spanish inquisition",
+			len:      39,
+			expected: "nobody expects the spanish inquisition",
+		},
+		{
+			input:    "nobody expects the spanish inquisition",
+			len:      30,
+			expected: "nobody expects ...ish inquisition",
+		},
+		{
+			input:    "nobody expects the spanish inquisition",
+			len:      38,
+			expected: "nobody expects the spanish inquisition",
+		},
+		{
+			input:    "",
+			len:      30,
+			expected: "",
+		},
+		{
+			input:    "",
+			len:      0,
+			expected: "",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.input+":"+strconv.Itoa(test.len), func(t *testing.T) {
+			assert.Equal(t, test.expected, TruncateMiddleEllipsis(test.input, test.len))
+		})
+	}
+}