[EXPERIMENTAL] Service framework (#1111)

Signed-off-by: Derek Collison <derek@nats.io>
Co-authored-by: Derek Collison <derek@nats.io>
Co-authored-by: Alberto Ricart Collison <alberto@synadia.com>
Co-authored-by: Piotr Piotrowski <piotr@synadia.com>

go.mod

@@ -5,4 +5,4 @@ go 1.16
 require (
 	github.com/nats-io/nkeys v0.3.0
 	github.com/nats-io/nuid v1.0.1
-)
+)

go.sum

@@ -8,4 +8,4 @@ golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

services/errors.go

@@ -0,0 +1,25 @@
+// Copyright 2022 The NATS Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package services
+
+import "fmt"
+
+type ServiceAPIError struct {
+	ErrorCode   int
+	Description string
+}
+
+func (e *ServiceAPIError) Error() string {
+	return fmt.Sprintf("%d %s", e.ErrorCode, e.Description)
+}