Add support for reading and saving config on Gateway. (#4463)

This is also a first step towards supporting bucket
notification for gateway.

cmd/common-main.go

@@ -0,0 +1,117 @@
+/*
+ * Minio Cloud Storage, (C) 2017 Minio, 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 cmd
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/minio/cli"
+)
+
+// Check for updates and print a notification message
+func checkUpdate(mode string) {
+	// Its OK to ignore any errors during getUpdateInfo() here.
+	if older, downloadURL, err := getUpdateInfo(1*time.Second, mode); err == nil {
+		if updateMsg := computeUpdateMessage(downloadURL, older); updateMsg != "" {
+			log.Println(updateMsg)
+		}
+	}
+}
+
+func enableLoggers() {
+	fileLogTarget := serverConfig.Logger.GetFile()
+	if fileLogTarget.Enable {
+		err := InitFileLogger(&fileLogTarget)
+		fatalIf(err, "Unable to initialize file logger")
+		log.AddTarget(fileLogTarget)
+	}
+
+	consoleLogTarget := serverConfig.Logger.GetConsole()
+	if consoleLogTarget.Enable {
+		InitConsoleLogger(&consoleLogTarget)
+	}
+
+	log.SetConsoleTarget(consoleLogTarget)
+}
+
+func initConfig() {
+	// Config file does not exist, we create it fresh and return upon success.
+	if isFile(getConfigFile()) {
+		fatalIf(migrateConfig(), "Config migration failed.")
+		fatalIf(loadConfig(), "Unable to load config version: '%s'.", v19)
+	} else {
+		fatalIf(newConfig(), "Unable to initialize minio config for the first time.")
+		log.Println("Created minio configuration file successfully at " + getConfigDir())
+	}
+}
+
+func handleCommonCmdArgs(ctx *cli.Context) {
+	// Set configuration directory.
+	{
+		// Get configuration directory from command line argument.
+		configDir := ctx.String("config-dir")
+		if !ctx.IsSet("config-dir") && ctx.GlobalIsSet("config-dir") {
+			configDir = ctx.GlobalString("config-dir")
+		}
+		if configDir == "" {
+			fatalIf(errors.New("empty directory"), "Configuration directory cannot be empty.")
+		}
+
+		// Disallow relative paths, figure out absolute paths.
+		configDirAbs, err := filepath.Abs(configDir)
+		fatalIf(err, "Unable to fetch absolute path for config directory %s", configDir)
+
+		setConfigDir(configDirAbs)
+	}
+}
+
+func handleCommonEnvVars() {
+	// Start profiler if env is set.
+	if profiler := os.Getenv("_MINIO_PROFILER"); profiler != "" {
+		globalProfiler = startProfiler(profiler)
+	}
+
+	// Check if object cache is disabled.
+	globalXLObjCacheDisabled = strings.EqualFold(os.Getenv("_MINIO_CACHE"), "off")
+
+	accessKey := os.Getenv("MINIO_ACCESS_KEY")
+	secretKey := os.Getenv("MINIO_SECRET_KEY")
+	if accessKey != "" && secretKey != "" {
+		cred, err := createCredential(accessKey, secretKey)
+		fatalIf(err, "Invalid access/secret Key set in environment.")
+
+		// credential Envs are set globally.
+		globalIsEnvCreds = true
+		globalActiveCred = cred
+	}
+
+	if browser := os.Getenv("MINIO_BROWSER"); browser != "" {
+		browserFlag, err := ParseBrowserFlag(browser)
+		if err != nil {
+			fatalIf(errors.New("invalid value"), "Unknown value ‘%s’ in MINIO_BROWSER environment variable.", browser)
+		}
+
+		// browser Envs are set globally, this does not represent
+		// if browser is turned off or on.
+		globalIsEnvBrowser = true
+		globalIsBrowserEnabled = bool(browserFlag)
+	}
+}