commands: adapt to command & p9 API changes

This changes signatures of execute functions to accept a slice of
"options" instead of a type of "settings", effectively shifting the
responsibility of initializing default settings and applying
modifications; into the execute function itself, rather than relying on
the caller to do so correctly and consistently.
I.e. empty calls from the CLI and Go API should always have the same
behaviour.
In addition, lazy initialization can be done later (and more clearly),
if needed at all.

Help text has been populated and formatted in a way that should look
acceptable when printed on ASCII typewriters, as well as ANSI terminals.

Some of the constraints for `p9` changed slightly, so calls have been
updated.

Author: djdv

internal/commands/client.go

@@ -24,8 +24,10 @@ type (
 	clientSettings struct {
 		serviceMaddr multiaddr.Multiaddr
 		exitInterval time.Duration
-		commonSettings
+		sharedSettings
 	}
+	clientOption  func(*clientSettings) error
+	clientOptions []clientOption
 	// defaultClientMaddr distinguishes
 	// the default maddr value, from an arbitrary maddr value.
 	// I.e. even if the underlying multiaddrs are the same
@@ -34,57 +36,80 @@ type (
 	defaultClientMaddr struct{ multiaddr.Multiaddr }
 )
 
-const errServiceNotFound = generic.ConstError("could not find service instance")
+const (
+	exitIntervalDefault = 30 * time.Second
+	errServiceNotFound  = generic.ConstError("could not find service instance")
+)
 
-func (set *clientSettings) getClient(autoLaunchDaemon bool) (*Client, error) {
+func (cs *clientSettings) getClient(autoLaunchDaemon bool) (*Client, error) {
 	var (
-		serviceMaddr = set.serviceMaddr
+		serviceMaddr = cs.serviceMaddr
 		clientOpts   []p9.ClientOpt
 	)
-	if set.verbose {
+	if cs.verbose {
 		// TODO: less fancy prefix and/or out+prefix from CLI flags
 		clientLog := log.New(os.Stdout, "⬇️ client - ", log.Lshortfile)
 		clientOpts = append(clientOpts, p9.WithClientLogger(clientLog))
 	}
 	if autoLaunchDaemon {
 		if _, wasUnset := serviceMaddr.(defaultClientMaddr); wasUnset {
-			return connectOrLaunchLocal(set.exitInterval, clientOpts...)
+			return connectOrLaunchLocal(cs.exitInterval, clientOpts...)
 		}
 	}
 	return Connect(serviceMaddr, clientOpts...)
 }
 
-func (set *clientSettings) BindFlags(flagSet *flag.FlagSet) {
-	set.commonSettings.BindFlags(flagSet)
+func (co *clientOptions) BindFlags(flagSet *flag.FlagSet) {
+	var sharedOptions sharedOptions
+	(&sharedOptions).BindFlags(flagSet)
+	*co = append(*co, func(cs *clientSettings) error {
+		subset, err := sharedOptions.make()
+		if err != nil {
+			return err
+		}
+		cs.sharedSettings = subset
+		return nil
+	})
 	const (
-		exitFlag  = exitAfterFlagName
+		exitName  = exitAfterFlagName
 		exitUsage = "passed to the daemon command if we launch it" +
 			"\n(refer to daemon's helptext)"
-		exitAfterDefault = 30 * time.Second
 	)
-	flagSet.DurationVar(&set.exitInterval, exitFlag, exitAfterDefault, exitUsage)
-	const (
-		sockName  = serverFlagName
-		sockUsage = "file system service `maddr`" +
-			"\n\b" // Newline for default value, sans space.
-	)
-	var sockDefaultText string
-	{
-		maddrs, err := userServiceMaddrs()
-		if err != nil {
-			panic(err)
-		}
-		sockDefault := maddrs[0]
-		sockDefaultText = sockDefault.String()
-		set.serviceMaddr = defaultClientMaddr{sockDefault}
+	flagSetFunc(flagSet, exitName, exitUsage, co,
+		func(value time.Duration, settings *clientSettings) error {
+			settings.exitInterval = value
+			return nil
+		})
+	flagSet.Lookup(exitName).
+		DefValue = exitIntervalDefault.String()
+	const serverUsage = "file system service `maddr`"
+	flagSetFunc(flagSet, serverFlagName, serverUsage, co,
+		func(value multiaddr.Multiaddr, settings *clientSettings) error {
+			settings.serviceMaddr = value
+			return nil
+		})
+	flagSet.Lookup(serverFlagName).
+		DefValue = defaultServerMaddr().String()
+}
+
+func (co clientOptions) make() (clientSettings, error) {
+	settings := clientSettings{
+		exitInterval: exitIntervalDefault,
 	}
-	flagSet.Func(sockName, sockUsage, func(s string) (err error) {
-		set.serviceMaddr, err = multiaddr.NewMultiaddr(s)
-		return
-	})
-	setDefaultValueText(flagSet, flagDefaultText{
-		sockName: sockDefaultText,
-	})
+	if err := applyOptions(&settings, co...); err != nil {
+		return clientSettings{}, err
+	}
+	if err := settings.fillDefaults(); err != nil {
+		return clientSettings{}, err
+	}
+	return settings, nil
+}
+
+func (cs *clientSettings) fillDefaults() error {
+	if cs.serviceMaddr == nil {
+		cs.serviceMaddr = defaultServerMaddr()
+	}
+	return nil
 }
 
 func (c *Client) getListeners() ([]multiaddr.Multiaddr, error) {