From b85289e5b75e2b6e83fc90f7639b54ea2b3b8a59 Mon Sep 17 00:00:00 2001
From: Aliaksandr Babai <aliaksandr.babai@gmail.com>
Date: Wed, 21 Feb 2024 16:39:40 +0100
Subject: [PATCH] feat: error handling

---
 error.go | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 error.go

diff --git a/error.go b/error.go
new file mode 100644
index 0000000..679bb71
--- /dev/null
+++ b/error.go
@@ -0,0 +1,63 @@
+package kafka
+
+import (
+	"context"
+)
+
+// Error is an error with an associated [Message] providing additional context.
+type Error struct {
+	Message Message
+	Err     error
+}
+
+// Error returns the original error message without modifications.
+func (err Error) Error() string {
+	return err.Err.Error()
+}
+
+// Unwrap returns the original error.
+func (err Error) Unwrap() error {
+	return err.Err
+}
+
+// Handler is an interface for processing errors.
+type ErrorHandler interface {
+	Handle(ctx context.Context, err error)
+}
+
+// ErrorHandlerFunc is an adapter type that allows the use of ordinary functions as an [ErrorHandler].
+type ErrorHandlerFunc func(ctx context.Context, err error)
+
+// Handle calls itself passing all arguments through.
+func (fn ErrorHandlerFunc) Handle(ctx context.Context, err error) {
+	fn(ctx, err)
+}
+
+// WrapErrorMiddleware returns a middleware that wraps errors with additional context using the Error type.
+func WrapErrorMiddleware() Middleware {
+	return func(next Handler) Handler {
+		return HandlerFunc(func(ctx context.Context, msg Message) error {
+			if err := next.Handle(ctx, msg); err != nil {
+				return Error{
+					Message: msg,
+					Err:     err,
+				}
+			}
+
+			return nil
+		})
+	}
+}
+
+// CatchErrorMiddleware returns a middleware that catches and handles errors without propagation.
+func CatchErrorMiddleware(eh ErrorHandler) Middleware {
+	return func(next Handler) Handler {
+		return HandlerFunc(func(ctx context.Context, msg Message) error {
+			if err := next.Handle(ctx, msg); err != nil {
+				eh.Handle(ctx, err)
+			}
+
+			return nil
+		})
+	}
+}