Merge pull request #325 from atc0005/i324-rework-config-handling-to-u…

…se-app-types

Refactor config logic to support app types

cmd/check_imap_mailbox/main.go

@@ -31,13 +31,8 @@ func main() {
 	// defer this from the start so it is the last deferred function to run
 	defer nagiosExitState.ReturnCheckResults()
 
-	// Setup configuration by parsing user-provided flags. This plugin does
-	// not currently support retrieving settings from a user-provided config
-	// file. Because this may change in the near future, we are structuring
-	// this plugin in a way to support that direction.
-	useConfigFile := false
-	useLogFile := false
-	cfg, cfgErr := config.New(useConfigFile, useLogFile)
+	// Setup configuration by parsing user-provided flags.
+	cfg, cfgErr := config.New(config.AppType{PluginIMAPMailboxBasicAuth: true})
 	switch {
 	case errors.Is(cfgErr, config.ErrVersionRequested):
 		fmt.Println(config.Version())

cmd/list-emails/main.go

@@ -40,9 +40,7 @@ func main() {
 	}(&appExitStatus)
 
 	// Setup configuration by parsing user-provided flags
-	useConfigFile := true
-	useLogFile := true
-	cfg, cfgErr := config.New(useConfigFile, useLogFile)
+	cfg, cfgErr := config.New(config.AppType{ReporterIMAPMailboxBasicAuth: true})
 	switch {
 	case errors.Is(cfgErr, config.ErrVersionRequested):
 		fmt.Println(config.Version())

internal/config/config.go

@@ -39,9 +39,41 @@ var Usage = func() {
 	flag.PrintDefaults()
 }
 
-// ErrVersionRequested indicates that the user requested application version
-// information
-var ErrVersionRequested = errors.New("version information requested")
+var (
+	// ErrVersionRequested indicates that the user requested application
+	// version information
+	ErrVersionRequested = errors.New("version information requested")
+
+	// ErrAppTypeNotSpecified indicates that a tool in this project failed to
+	// specify a valid application type.
+	ErrAppTypeNotSpecified = errors.New("valid app type not specified")
+)
+
+// AppType represents the type of application that is being
+// configured/initialized. Not all application types will use the same
+// features and as a result will not accept the same flags. Unless noted
+// otherwise, each of the application types are incompatible with each other,
+// though some flags are common to all types.
+type AppType struct {
+
+	// PluginIMAPMailboxBasicAuth represents an application used as a
+	// monitoring plugin for evaluating IMAP mailboxes.
+	//
+	// Basic Authentication is used to login.
+	PluginIMAPMailboxBasicAuth bool
+
+	// ReporterIMAPMailboxBasicAuth represents an application used for
+	// generating reports for specified IMAP mailboxes.
+	//
+	// Unlike an Inspector application which is focused on testing or
+	// gathering specific details for troubleshooting purposes or a monitoring
+	// plugin which is intended for providing a severity-based outcome, a
+	// Reporter application is intended for gathering information as an
+	// overview.
+	//
+	// Basic Authentication is used to login.
+	ReporterIMAPMailboxBasicAuth bool
+}
 
 // MailAccount represents an email account listed within a configuration file.
 type MailAccount struct {
@@ -169,29 +201,29 @@ func Branding(msg string) func() string {
 // provided flag and config file values. It is responsible for validating
 // user-provided values and initializing the logging settings used by this
 // application.
-func New(useConfigFile bool, useLogFile bool) (*Config, error) {
+func New(appType AppType) (*Config, error) {
 	var config Config
 
-	config.handleFlagsConfig(useConfigFile)
+	config.handleFlagsConfig(appType)
 
 	if config.ShowVersion {
 		return nil, ErrVersionRequested
 	}
 
-	if err := config.validate(useConfigFile); err != nil {
+	if err := config.validate(appType); err != nil {
 		return nil, fmt.Errorf("configuration validation failed: %w", err)
 	}
 
 	// initialize logging "early", just as soon as validation is complete so
 	// that we can rely on it to debug further configuration init work
-	if err := config.setupLogging(useLogFile); err != nil {
+	if err := config.setupLogging(appType); err != nil {
 		return nil, fmt.Errorf(
 			"failed to set logging configuration: %w",
 			err,
 		)
 	}
 
-	if useConfigFile {
+	if appType.ReporterIMAPMailboxBasicAuth {
 		if err := config.load(); err != nil {
 
 			// We log this message in an effort to populate the log file with
@@ -211,102 +243,6 @@ func New(useConfigFile bool, useLogFile bool) (*Config, error) {
 
 }
 
-// validate verifies all Config struct fields have been provided acceptable
-// values.
-func (c Config) validate(useConfigFile bool) error {
-
-	// NOTE: It's fine to *not* specify a config file. The expected behavior
-	// is that specifying a config file will be a rare thing; users will more
-	// often than not rely on config file auto-detection behavior.
-	//
-	// That said, if a user does not specify a config file, we need to require
-	// that one was found and loaded.
-	//
-	// if useConfigFile {
-	// 	if c.ConfigFile == "" {
-	// 		return fmt.Errorf("config file required, but not specified")
-	// 	}
-	// }
-
-	for _, account := range c.Accounts {
-		if account.Folders == nil {
-			return fmt.Errorf(
-				"one or more folders not provided for account %s",
-				account.Name,
-			)
-		}
-
-		if account.Port < 0 {
-			return fmt.Errorf(
-				"invalid TCP port number %d provided for account %s",
-				account.Port,
-				account.Name,
-			)
-		}
-
-		if account.Username == "" {
-			return fmt.Errorf("username not provided for account %s",
-				account.Name,
-			)
-		}
-
-		if account.Password == "" {
-			return fmt.Errorf("password not provided for account %s",
-				account.Name,
-			)
-		}
-
-		if account.Server == "" {
-			return fmt.Errorf("server FQDN not provided for account %s",
-				account.Name,
-			)
-		}
-	}
-
-	// these settings only apply to the list-emails application
-	if useConfigFile {
-
-		// set with a default value if not specified by the user, so should not
-		// ever be empty
-		if c.ReportFileOutputDir == "" {
-			return fmt.Errorf("missing report file output directory")
-		}
-
-		// set with a default value if not specified by the user, so should not
-		// ever be empty
-		if c.LogFileOutputDir == "" {
-			return fmt.Errorf("missing log file output directory")
-		}
-
-	}
-
-	switch strings.ToLower(c.minTLSVersion) {
-	case minTLSVersion10:
-	case minTLSVersion11:
-	case minTLSVersion12:
-	case minTLSVersion13:
-	default:
-		return fmt.Errorf("invalid TLS version keyword: %s", c.minTLSVersion)
-	}
-
-	switch strings.ToLower(c.NetworkType) {
-	case netTypeTCPAuto:
-	case netTypeTCP4:
-	case netTypeTCP6:
-	default:
-		return fmt.Errorf("invalid network type keyword: %s", c.NetworkType)
-	}
-
-	requestedLoggingLevel := strings.ToLower(c.LoggingLevel)
-	if _, ok := loggingLevels[requestedLoggingLevel]; !ok {
-		return fmt.Errorf("invalid logging level %s", c.LoggingLevel)
-	}
-
-	// Optimist
-	return nil
-
-}
-
 // load is a helper function to handle the bulk of the configuration loading
 // work for the New constructor function.
 func (c *Config) load() error {

internal/config/flags.go

@@ -10,11 +10,11 @@ package config
 import "flag"
 
 // handleFlagsConfig handles toggling the exposure of specific configuration
-// flags to the user. This behavior is controlled via a boolean value
-// initially set by each cmd. If enabled, a smaller subset of flags specific
-// to the list-emails cmd is exposed, otherwise the set of flags specific to
-// the Nagios plugin are exposed and processed.
-func (c *Config) handleFlagsConfig(acceptConfigFile bool) {
+// flags to the user. This behavior is controlled via the specified
+// application type as set by each cmd. Based on the application's specified
+// type, a smaller subset of flags specific to each type are exposed along
+// with a set common to all application types.
+func (c *Config) handleFlagsConfig(appType AppType) {
 
 	var account MailAccount
 
@@ -25,20 +25,22 @@ func (c *Config) handleFlagsConfig(acceptConfigFile bool) {
 	flag.StringVar(&c.minTLSVersion, "min-tls", defaultMinTLSVersion, minTLSVersionFlagHelp)
 
 	// currently only applies to list-emails app, don't expose to Nagios plugin
-	if acceptConfigFile {
+	if appType.ReporterIMAPMailboxBasicAuth {
 		flag.StringVar(&c.ConfigFile, "config-file", defaultINIConfigFileName, iniConfigFileFlagHelp)
 		flag.StringVar(&c.ReportFileOutputDir, "report-file-dir", defaultReportFileOutputDir, reportFileOutputDirFlagHelp)
 		flag.StringVar(&c.LogFileOutputDir, "log-file-dir", defaultLogFileOutputDir, logFileOutputDirFlagHelp)
 	}
 
 	// currently only applies to Nagios plugin
-	if !acceptConfigFile {
+	if appType.PluginIMAPMailboxBasicAuth {
 		flag.Var(&account.Folders, "folders", foldersFlagHelp)
 		flag.StringVar(&account.Username, "username", defaultUsername, usernameFlagHelp)
 		flag.StringVar(&account.Password, "password", defaultPassword, passwordFlagHelp)
 		flag.StringVar(&account.Server, "server", defaultServer, serverFlagHelp)
 		flag.IntVar(&account.Port, "port", defaultPort, portFlagHelp)
 		flag.BoolVar(&c.EmitBranding, "branding", defaultEmitBranding, emitBrandingFlagHelp)
+
+		c.Accounts = append(c.Accounts, account)
 	}
 
 	// Allow our function to override the default Help output
@@ -47,10 +49,4 @@ func (c *Config) handleFlagsConfig(acceptConfigFile bool) {
 	// parse flag definitions from the argument list
 	flag.Parse()
 
-	// if CLI-provided values were given then record those as an entry in the
-	// list
-	if !acceptConfigFile {
-		c.Accounts = append(c.Accounts, account)
-	}
-
 }

internal/config/logging.go

@@ -96,14 +96,17 @@ func setLoggingLevel(logLevel string) error {
 
 // setupLogging is responsible for configuring logging settings for this
 // application
-func (c *Config) setupLogging(useLogFile bool) error {
+func (c *Config) setupLogging(appType AppType) error {
 
 	var logOutput io.Writer
 
+	var useLogFile bool
+	switch {
+
 	// we want to log to a file only for list-emails
+	case appType.ReporterIMAPMailboxBasicAuth:
 
-	switch {
-	case useLogFile:
+		useLogFile = true
 
 		logFilename := fmt.Sprintf(
 			logFilenameTemplate,
@@ -136,6 +139,10 @@ func (c *Config) setupLogging(useLogFile bool) error {
 		// TODO: Set c.LogFileHandle to the newly opened file
 	default:
 
+		// Explicitly note that we disable use of a log file for all
+		// other application types.
+		useLogFile = false
+
 		// Nagios doesn't look at stderr, only stdout. We have to make sure
 		// that only whatever output is meant for consumption is emitted to
 		// stdout and whatever is meant for troubleshooting is sent to stderr.