use cached netconf to avoid delete loop (#160)

* use cached netconf to avoid delete loop

Signed-off-by: Periyasamy Palanisamy <[email protected]>

* merge two cache writes into single write

Signed-off-by: Periyasamy Palanisamy <[email protected]>

* address review comments

Signed-off-by: Periyasamy Palanisamy <[email protected]>

* improve cache api

Signed-off-by: Periyasamy Palanisamy <[email protected]>

* address review comments (part-2)

Signed-off-by: Periyasamy Palanisamy <[email protected]>

* make cmd delete to rely on cache logic

Signed-off-by: Periyasamy Palanisamy <[email protected]>

pkg/config/config.go

@@ -0,0 +1,142 @@
+// Copyright (c) 2021 Red Hat, Inc.
+// Copyright (c) 2021 CNI authors
+// Copyright (c) 2021 Nordix Foundation.
+//
+// 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 config
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/imdario/mergo"
+	"github.com/k8snetworkplumbingwg/ovs-cni/pkg/types"
+	"github.com/k8snetworkplumbingwg/ovs-cni/pkg/utils"
+)
+
+const (
+	linkstateCheckRetries  = 5
+	linkStateCheckInterval = 600 // in milliseconds
+)
+
+// LoadConf parses and validates stdin netconf and returns NetConf object
+func LoadConf(data []byte) (*types.NetConf, error) {
+	netconf, err := loadNetConf(data)
+	if err != nil {
+		return nil, err
+	}
+	flatNetConf, err := loadFlatNetConf(netconf.ConfigurationPath)
+	if err != nil {
+		return nil, err
+	}
+	netconf, err = mergeConf(netconf, flatNetConf)
+	if err != nil {
+		return nil, err
+	}
+	if netconf.LinkStateCheckRetries == 0 {
+		netconf.LinkStateCheckRetries = linkstateCheckRetries
+	}
+
+	if netconf.LinkStateCheckInterval == 0 {
+		netconf.LinkStateCheckInterval = linkStateCheckInterval
+	}
+	return netconf, nil
+}
+
+// LoadConfFromCache retrieve net config from cache
+func LoadConfFromCache(cRef string) (*types.CachedNetConf, error) {
+	netCache := &types.CachedNetConf{}
+	netConfBytes, err := utils.ReadCache(cRef)
+	if err != nil {
+		return nil, fmt.Errorf("error reading cached NetConf with name %s: %v", cRef, err)
+	}
+
+	if err = json.Unmarshal(netConfBytes, netCache); err != nil {
+		return nil, fmt.Errorf("failed to parse NetConf: %v", err)
+	}
+
+	return netCache, nil
+}
+
+// GetCRef unique identifier for a container interface
+func GetCRef(cid, podIfName string) string {
+	return strings.Join([]string{cid, podIfName}, "-")
+}
+
+func loadNetConf(bytes []byte) (*types.NetConf, error) {
+	netconf := &types.NetConf{}
+	if err := json.Unmarshal(bytes, netconf); err != nil {
+		return nil, fmt.Errorf("failed to load netconf: %v", err)
+	}
+
+	return netconf, nil
+}
+
+func loadFlatNetConf(configPath string) (*types.NetConf, error) {
+	confFiles := getOvsConfFiles()
+	if configPath != "" {
+		confFiles = append([]string{configPath}, confFiles...)
+	}
+
+	// loop through the path and parse the JSON config
+	flatNetConf := &types.NetConf{}
+	for _, confFile := range confFiles {
+		confExists, err := pathExists(confFile)
+		if err != nil {
+			return nil, fmt.Errorf("error checking ovs config file: error: %v", err)
+		}
+		if confExists {
+			jsonFile, err := os.Open(confFile)
+			if err != nil {
+				return nil, fmt.Errorf("open ovs config file %s error: %v", confFile, err)
+			}
+			defer jsonFile.Close()
+			jsonBytes, err := ioutil.ReadAll(jsonFile)
+			if err != nil {
+				return nil, fmt.Errorf("load ovs config file %s: error: %v", confFile, err)
+			}
+			if err := json.Unmarshal(jsonBytes, flatNetConf); err != nil {
+				return nil, fmt.Errorf("parse ovs config file %s: error: %v", confFile, err)
+			}
+			break
+		}
+	}
+
+	return flatNetConf, nil
+}
+
+func mergeConf(netconf, flatNetConf *types.NetConf) (*types.NetConf, error) {
+	if err := mergo.Merge(netconf, flatNetConf); err != nil {
+		return nil, fmt.Errorf("merge with ovs config file: error: %v", err)
+	}
+	return netconf, nil
+}
+
+func pathExists(path string) (bool, error) {
+	_, err := os.Stat(path)
+	if err == nil {
+		return true, nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return false, err
+}
+
+func getOvsConfFiles() []string {
+	return []string{"/etc/kubernetes/cni/net.d/ovs.d/ovs.conf", "/etc/cni/net.d/ovs.d/ovs.conf"}
+}