Merge pull request #14789 from saschagrunert/libpod-errors

libpod/runtime: switch to golang native error wrapping

2 files changed, 73 insertions, 1 deletions

diff --git a/pkg/errorhandling/errorhandling.go b/pkg/errorhandling/errorhandling.go
index fc6772c08..9b456c9c0 100644
--- a/pkg/errorhandling/errorhandling.go
+++ b/pkg/errorhandling/errorhandling.go
@@ -1,11 +1,11 @@
 package errorhandling
 
 import (
+	"errors"
 	"os"
 	"strings"
 
 	"github.com/hashicorp/go-multierror"
-	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
@@ -121,3 +121,22 @@ func (e PodConflictErrorModel) Error() string {
 func (e PodConflictErrorModel) Code() int {
 	return 409
 }
+
+// Cause returns the most underlying error for the provided one. There is a
+// maximum error depth of 100 to avoid endless loops. An additional error log
+// message will be created if this maximum has reached.
+func Cause(err error) (cause error) {
+	cause = err
+
+	const maxDepth = 100
+	for i := 0; i <= maxDepth; i++ {
+		res := errors.Unwrap(cause)
+		if res == nil {
+			return cause
+		}
+		cause = res
+	}
+
+	logrus.Errorf("Max error depth of %d reached, cannot unwrap until root cause: %v", maxDepth, err)
+	return cause
+}
diff --git a/pkg/errorhandling/errorhandling_test.go b/pkg/errorhandling/errorhandling_test.go
new file mode 100644
index 000000000..ec720c5e7
--- /dev/null
+++ b/pkg/errorhandling/errorhandling_test.go
@@ -0,0 +1,53 @@
+package errorhandling
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCause(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range []struct {
+		name        string
+		err         func() error
+		expectedErr error
+	}{
+		{
+			name:        "nil error",
+			err:         func() error { return nil },
+			expectedErr: nil,
+		},
+		{
+			name:        "equal errors",
+			err:         func() error { return errors.New("foo") },
+			expectedErr: errors.New("foo"),
+		},
+		{
+			name:        "wrapped error",
+			err:         func() error { return fmt.Errorf("baz: %w", fmt.Errorf("bar: %w", errors.New("foo"))) },
+			expectedErr: errors.New("foo"),
+		},
+		{
+			name: "max depth reached",
+			err: func() error {
+				err := errors.New("error")
+				for i := 0; i <= 101; i++ {
+					err = fmt.Errorf("%d: %w", i, err)
+				}
+				return err
+			},
+			expectedErr: fmt.Errorf("0: %w", errors.New("error")),
+		},
+	} {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			err := Cause(tc.err())
+			assert.Equal(t, tc.expectedErr, err)
+		})
+	}
+}