HookState adhears to OCI

Signed-off-by: George Lestaris <glestaris@pivotal.io>
Signed-off-by: Ed King <eking@pivotal.io>

libcontainer/utils/utils.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 	"syscall"
 )
 
@@ -84,3 +85,18 @@ func CleanPath(path string) string {
 	// Clean the path again for good measure.
 	return filepath.Clean(path)
 }
+
+// SearchLabels searches a list of key-value pairs for the provided key and
+// returns the corresponding value. The pairs must be separated with '='.
+func SearchLabels(labels []string, query string) string {
+	for _, l := range labels {
+		parts := strings.SplitN(l, "=", 2)
+		if len(parts) < 2 {
+			continue
+		}
+		if parts[0] == query {
+			return parts[1]
+		}
+	}
+	return ""
+}

libcontainer/utils/utils_test.go

@@ -23,3 +23,24 @@ func TestGenerateName(t *testing.T) {
 		t.Fatalf("expected name to be %d chars but received %d", expected, len(name))
 	}
 }
+
+var labelTest = []struct {
+	labels        []string
+	query         string
+	expectedValue string
+}{
+	{[]string{"bundle=/path/to/bundle"}, "bundle", "/path/to/bundle"},
+	{[]string{"test=a", "test=b"}, "bundle", ""},
+	{[]string{"bundle=a", "test=b", "bundle=c"}, "bundle", "a"},
+	{[]string{"", "test=a", "bundle=b"}, "bundle", "b"},
+	{[]string{"test", "bundle=a"}, "bundle", "a"},
+	{[]string{"test=a", "bundle="}, "bundle", ""},
+}
+
+func TestSearchLabels(t *testing.T) {
+	for _, tt := range labelTest {
+		if v := SearchLabels(tt.labels, tt.query); v != tt.expectedValue {
+			t.Errorf("expected value '%s' for query '%s'; got '%s'", tt.expectedValue, tt.query, v)
+		}
+	}
+}