Add metadata helper generator

Signed-off-by: Vladimir Popov <vladimir.popov@xored.com>

pkg/networkservice/utils/metadata/README.md

@@ -0,0 +1,74 @@
+# Metadata helper
+
+Metadata helper generation script has 2 input parameters:
+* output - output file name
+* type - name<isClient,type>:
+    * name - prefix for metadata type, constructor
+    * isClient - metadata.Map(ctx, isClient)
+    * type - stored type
+
+gen.go:
+```go
+package connect
+
+//go:generate bash ../../utils/metadata/helper.sh -output metadata_helper.gen.go -type nsClient<false,*github.com/networkservicemesh/api/pkg/api/networkservice.NetworkServiceClient>
+```
+metadata_helper.gen.go:
+```go
+// Code generated by "-output metadata_helper.gen.go -type nsClient<false,*github.com/networkservicemesh/api/pkg/api/networkservice.NetworkServiceClient>"; DO NOT EDIT.
+package connect
+
+import (
+	"context"
+	"sync"
+
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
+
+	"github.com/networkservicemesh/sdk/pkg/networkservice/utils/metadata"
+)
+
+const (
+	_networkservice_NetworkServiceClientKey _networkservice_NetworkServiceClientKeyType = "_networkservice_NetworkServiceClient"
+)
+
+type _networkservice_NetworkServiceClientKeyType string
+
+var _nil__networkservice_NetworkServiceClient = func() (val *networkservice.NetworkServiceClient) { return }()
+
+type nsClientMetadataHelper struct {
+	m *sync.Map
+}
+
+func nsClientMetaData(ctx context.Context) *nsClientMetadataHelper {
+	return &nsClientMetadataHelper{
+		m: metadata.Map(ctx, false),
+	}
+}
+
+func (h *nsClientMetadataHelper) store(value *networkservice.NetworkServiceClient) {
+	h.m.Store(_networkservice_NetworkServiceClientKey, value)
+}
+
+func (h *nsClientMetadataHelper) loadOrStore(value *networkservice.NetworkServiceClient) (*networkservice.NetworkServiceClient, bool) {
+	raw, ok := h.m.LoadOrStore(_networkservice_NetworkServiceClientKey, value)
+	return raw.(*networkservice.NetworkServiceClient), ok
+}
+
+func (h *nsClientMetadataHelper) load() (*networkservice.NetworkServiceClient, bool) {
+	if raw, ok := h.m.Load(_networkservice_NetworkServiceClientKey); ok {
+		return raw.(*networkservice.NetworkServiceClient), true
+	}
+	return _nil__networkservice_NetworkServiceClient, false
+}
+
+func (h *nsClientMetadataHelper) loadAndDelete() (*networkservice.NetworkServiceClient, bool) {
+	if raw, ok := h.m.LoadAndDelete(_networkservice_NetworkServiceClientKey); ok {
+		return raw.(*networkservice.NetworkServiceClient), true
+	}
+	return _nil__networkservice_NetworkServiceClient, false
+}
+
+func (h *nsClientMetadataHelper) delete() {
+	h.m.Delete(_networkservice_NetworkServiceClientKey)
+}
+```

pkg/networkservice/utils/metadata/helper.sh

@@ -0,0 +1,134 @@
+#!/bin/bash +x
+# shellcheck disable=SC2002,SC2181
+
+# Copyright (c) 2020 Doc.ai and/or its affiliates.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# 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.
+
+LINE="$*"
+
+###########################
+## Parse arguments
+###########################
+
+OUTPUT=
+TYPE=
+while [[ $# -gt 0 ]]; do
+  if [[ "$1" == "-output" ]]; then
+    OUTPUT="$2"
+    shift 2
+  elif [[ "$1" == "-type" ]]; then
+    TYPE="$2"
+    shift 2
+  else
+    echo "usage: $0 -output file.gen.go -type name<isClient,type>" && exit 1
+  fi
+done
+
+if [[ "${OUTPUT}" == "" ]] || [[ "${TYPE}" == "" ]]; then
+  echo "usage: $0 -output file.gen.go -type name<isClient,type>" && exit 1
+fi
+
+###########################
+## Parse package
+###########################
+
+ls gen.go >/dev/null 2>/dev/null
+if [[ $? -ne 0 ]]; then
+  echo "no gen.go file found" && exit 2
+fi
+package="$(cat gen.go | grep -e "package .*" | sed -E "s/package (.*)/\1/g")"
+
+###########################
+## Prepare types
+###########################
+
+name=$(echo "${TYPE}" | sed -E "s/(.*)<.*>/\1/g")
+is_client=$(echo "${TYPE}" | sed -E "s/.*<(.*),.*>/\1/g")
+type=$(echo "${TYPE}" | sed -E "s/.*<.*,(.*)>/\1/g")
+
+type_package=$(echo "${type}" | sed -E "s/\**(.*\/.*)\..*/\1/g")
+type_name=$(echo "${type}" | sed -E "s/(\**).*\/(.*\..*)/\1\2/g")
+if [[ "${type_name}" != "${type_package}" ]]; then
+  type="${type_name}"
+fi
+
+type_formatted=$(echo "${type}" | sed -E "s/[\*\.\/]/_/g")
+
+###########################
+## Code
+###########################
+
+echo \
+  "// Code generated by \"${LINE}\"; DO NOT EDIT.
+package ${package}
+
+import (
+	\"context\"
+	\"sync\"" >"${OUTPUT}"
+if [[ "${type_name}" != "${type_package}" ]]; then
+  echo \
+    "
+	\"${type_package}\"" >>"${OUTPUT}"
+fi
+echo \
+  "
+	\"github.com/networkservicemesh/sdk/pkg/networkservice/utils/metadata\"
+)
+
+const (
+	${type_formatted}Key ${type_formatted}KeyType = \"${type_formatted}\"
+)
+
+type ${type_formatted}KeyType string
+
+var _nil_${type_formatted} = func() (val ${type}) { return }()
+
+type ${name}MetadataHelper struct {
+	m *sync.Map
+}
+
+func ${name}MetaData(ctx context.Context) *${name}MetadataHelper {
+	return &${name}MetadataHelper{
+		m: metadata.Map(ctx, ${is_client}),
+	}
+}
+
+func (h *${name}MetadataHelper) store(value ${type}) {
+	h.m.Store(${type_formatted}Key, value)
+}
+
+func (h *${name}MetadataHelper) loadOrStore(value ${type}) (${type}, bool) {
+	raw, ok := h.m.LoadOrStore(${type_formatted}Key, value)
+	return raw.(${type}), ok
+}
+
+func (h *${name}MetadataHelper) load() (${type}, bool) {
+	if raw, ok := h.m.Load(${type_formatted}Key); ok {
+		return raw.(${type}), true
+	}
+	return _nil_${type_formatted}, false
+}
+
+func (h *${name}MetadataHelper) loadAndDelete() (${type}, bool) {
+	if raw, ok := h.m.LoadAndDelete(${type_formatted}Key); ok {
+		return raw.(${type}), true
+	}
+	return _nil_${type_formatted}, false
+}
+
+func (h *${name}MetadataHelper) delete() {
+	h.m.Delete(${type_formatted}Key)
+}" >>"${OUTPUT}"