pkg/config: custom errors (#64)

go.mod

@@ -1,6 +1,6 @@
 module github.com/smartcontractkit/chainlink-relay
 
-go 1.17
+go 1.18
 
 require (
 	github.com/confluentinc/confluent-kafka-go v1.8.2

pkg/config/error.go

@@ -0,0 +1,33 @@
+package config
+
+import "fmt"
+
+// lightweight error types copied from core
+
+type ErrInvalid struct {
+	Name  string
+	Value any
+	Msg   string
+}
+
+func (e ErrInvalid) Error() string {
+	return fmt.Sprintf("%s: invalid value %v: %s", e.Name, e.Value, e.Msg)
+}
+
+type ErrMissing struct {
+	Name string
+	Msg  string
+}
+
+func (e ErrMissing) Error() string {
+	return fmt.Sprintf("%s: missing: %s", e.Name, e.Msg)
+}
+
+type ErrEmpty struct {
+	Name string
+	Msg  string
+}
+
+func (e ErrEmpty) Error() string {
+	return fmt.Sprintf("%s: empty: %s", e.Name, e.Msg)
+}