Move configuration into config files

Move k8splugin configuration into config files
instead of using environment variables.

Issue-ID: MULTICLOUD-579
Change-Id: I7b76d5a14d24f002a8db484097a31fb5e908b6f8
Signed-off-by: Kiran Kamineni <kiran.k.kamineni@intel.com>

2 files changed, 168 insertions, 0 deletions

diff --git a/src/k8splugin/internal/config/config.go b/src/k8splugin/internal/config/config.go
new file mode 100644
index 00000000..c3ca9054
--- /dev/null
+++ b/src/k8splugin/internal/config/config.go
@@ -0,0 +1,128 @@
+/*
+ * Copyright 2019 Intel Corporation, Inc
+ *
+ * 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"
+	"log"
+	"os"
+	"reflect"
+)
+
+// Configuration loads up all the values that are used to configure
+// backend implementations
+type Configuration struct {
+	CAFile            string `json:"ca-file"`
+	ServerCert        string `json:"server-cert"`
+	ServerKey         string `json:"server-key"`
+	Password          string `json:"password"`
+	DatabaseAddress   string `json:"database-address"`
+	DatabaseType      string `json:"database-type"`
+	PluginDir         string `json:"plugin-dir"`
+	EtcdIP            string `json:"etcd-ip"`
+	EtcdCert          string `json:"etcd-cert"`
+	EtcdKey           string `json:"etcd-key"`
+	EtcdCAFile        string `json:"etcd-ca-file"`
+	KubeConfigDir     string `json:"kube-config-dir"`
+	OVNCentralAddress string `json:"ovn-central-address"`
+}
+
+// Config is the structure that stores the configuration
+var gConfig *Configuration
+
+// readConfigFile reads the specified smsConfig file to setup some env variables
+func readConfigFile(file string) (*Configuration, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return defaultConfiguration(), err
+	}
+	defer f.Close()
+
+	// Setup some defaults here
+	// If the json file has values in it, the defaults will be overwritten
+	conf := defaultConfiguration()
+
+	// Read the configuration from json file
+	decoder := json.NewDecoder(f)
+	err = decoder.Decode(conf)
+	if err != nil {
+		return conf, err
+	}
+
+	return conf, nil
+}
+
+func defaultConfiguration() *Configuration {
+	cwd, err := os.Getwd()
+	if err != nil {
+		log.Println("Error getting cwd. Using .")
+		cwd = "."
+	}
+
+	return &Configuration{
+		CAFile:            "ca.cert",
+		ServerCert:        "server.cert",
+		ServerKey:         "server.key",
+		Password:          "",
+		DatabaseAddress:   "127.0.0.1",
+		DatabaseType:      "mongo",
+		PluginDir:         cwd,
+		EtcdIP:            "127.0.0.1",
+		EtcdCert:          "etcd.cert",
+		EtcdKey:           "etcd.key",
+		EtcdCAFile:        "etcd-ca.cert",
+		KubeConfigDir:     cwd,
+		OVNCentralAddress: "127.0.0.1",
+	}
+}
+
+// GetConfiguration returns the configuration for the app.
+// It will try to load it if it is not already loaded.
+func GetConfiguration() *Configuration {
+	if gConfig == nil {
+		conf, err := readConfigFile("k8sconfig.json")
+		if err != nil {
+			log.Println("Error loading config file. Using defaults.")
+		}
+		gConfig = conf
+	}
+
+	return gConfig
+}
+
+// SetConfigValue sets a value in the configuration
+// This is mostly used to customize the application and
+// should be used carefully.
+func SetConfigValue(key string, value string) *Configuration {
+	c := GetConfiguration()
+	if value == "" || key == "" {
+		return c
+	}
+
+	v := reflect.ValueOf(c).Elem()
+	if v.Kind() == reflect.Struct {
+		f := v.FieldByName(key)
+		if f.IsValid() {
+			if f.CanSet() {
+				if f.Kind() == reflect.String {
+					f.SetString(value)
+				}
+			}
+		}
+	}
+	return c
+}
diff --git a/src/k8splugin/internal/config/config_test.go b/src/k8splugin/internal/config/config_test.go
new file mode 100644
index 00000000..ddebfb27
--- /dev/null
+++ b/src/k8splugin/internal/config/config_test.go
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2019 Intel Corporation, Inc
+ *
+ * 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 (
+	"testing"
+)
+
+func TestReadConfigurationFile(t *testing.T) {
+	t.Run("Non Existent Configuration File", func(t *testing.T) {
+		_, err := readConfigFile("filedoesnotexist.json")
+		if err == nil {
+			t.Fatal("ReadConfiguationFile: Expected Error, got nil")
+		}
+	})
+
+	t.Run("Read Configuration File", func(t *testing.T) {
+		conf, err := readConfigFile("../../mock_files/mock_configs/mock_config.json")
+		if err != nil {
+			t.Fatal("ReadConfigurationFile: Error reading file")
+		}
+		if conf.DatabaseType != "mock_db_test" {
+			t.Fatal("ReadConfigurationFile: Incorrect entry read from file")
+		}
+	})
+}