console: add console implementation

The ‘Console’ module has been separate from the ‘Connect’ abstraction,
to allow it being used independently of the transport layer.

Part of #1050

cli/console/console.go

@@ -0,0 +1,258 @@
+package console
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+	"syscall"
+	"unicode"
+
+	"github.com/apex/log"
+	"golang.org/x/term"
+
+	"github.com/tarantool/go-prompt"
+)
+
+const (
+	maxLivePrefixIndent = 15
+	// see https://github.com/tarantool/tarantool/blob/b53cb2aeceedc39f356ceca30bd0087ee8de7c16/src/box/lua/console.c#L265
+	tarantoolWordSeparators = "\t\r\n !\"#$%&'()*+,-/;<=>?@[\\]^`{|}~"
+)
+
+var (
+	controlLeftBytes  = []byte{0x1b, 0x62}
+	controlRightBytes = []byte{0x1b, 0x66}
+)
+
+// ConsoleOpts collection console options to create new console.
+type ConsoleOpts struct {
+	// Handler is the implementation of command processor.
+	Handler Handler
+
+	// History if specified than save input commands with it.
+	History History
+
+	// Format options set how to formatting result.
+	Format Format
+}
+
+// Console implementation of active console handler.
+type Console struct {
+	impl              ConsoleOpts
+	internal          Handler // internal Handler execute console's additional backslash commands.
+	input             string
+	quit              bool
+	prefix            string
+	livePrefixEnabled bool
+	livePrefix        string
+	delimiter         string
+	prompt            *prompt.Prompt
+}
+
+// NewConsole creates a new console connected to the tarantool instance.
+func NewConsole(opts ConsoleOpts) (Console, error) {
+	if opts.Handler == nil {
+		return Console{quit: true}, errors.New("no handler for commands has been set")
+	}
+	c := Console{
+		impl: opts,
+		quit: false,
+	}
+	c.setPrefix()
+	return c, nil
+}
+
+func (c *Console) runOnPipe() {
+	log.Debugf("Processing piped input")
+	pipe := bufio.NewScanner(os.Stdin)
+	for pipe.Scan() {
+		line := pipe.Text()
+		c.execute(line)
+	}
+}
+
+// Run starts console.
+func (c *Console) Run() error {
+	if c.quit {
+		return errors.New("can't run on stopped console")
+	}
+	if !term.IsTerminal(syscall.Stdin) {
+		c.runOnPipe()
+		return nil
+	}
+
+	log.Infof("Connected to %s\n", c.title())
+	c.prompt = prompt.New(
+		c.execute,
+		c.complete,
+		c.getPromptOptions()...,
+	)
+	c.prompt.Run()
+
+	return nil
+}
+
+// Close frees up resources used by the console.
+func (c *Console) Close() {
+	c.impl.Handler.Stop()
+	if c.impl.History != nil {
+		c.impl.History.Stop()
+	}
+}
+
+// executeEmbeddedCommand try process additional backslash commands.
+func (c *Console) executeEmbeddedCommand(in string) bool {
+	if c.input == "" && c.internal != nil {
+		if c.internal.Execute(in) != nil {
+			if c.quit {
+				c.Close()
+				log.Infof("Quit from the console")
+				os.Exit(0)
+			}
+			return true
+		}
+	}
+	return false
+}
+
+// cleanupDelimiter checks if the input statement ends with the string `c.delimiter`.
+// If yes, it removes it. Returns true if the delimiter has been removed.
+func (c *Console) cleanupDelimiter() bool {
+	if c.delimiter == "" {
+		return true
+	}
+	no_space := strings.TrimRightFunc(c.input, func(r rune) bool {
+		return unicode.IsSpace(r)
+	})
+	no_delim := strings.TrimSuffix(no_space, c.delimiter)
+	if len(no_space) > len(no_delim) {
+		c.input = no_delim
+		return true
+	}
+	return false
+}
+
+// addStmt adds a new part of the statement.
+// It returns true if the statement is already completed.
+func (c *Console) addStmt(part string) bool {
+	if c.input == "" {
+		trimmed := strings.TrimSpace(part)
+		if trimmed != "" {
+			c.input = part
+		}
+	} else {
+		c.input += "\n" + part
+	}
+
+	has_delim := c.cleanupDelimiter()
+	c.livePrefixEnabled = !(has_delim && c.impl.Handler.Validate(c.input))
+	return !c.livePrefixEnabled
+}
+
+// execute called from prompt to process input.
+func (c *Console) execute(in string) {
+	if c.executeEmbeddedCommand(in) || !c.addStmt(in) {
+		return
+	}
+
+	trimmed := strings.TrimSpace(c.input)
+	if c.impl.History != nil {
+		c.impl.History.AppendCommand(trimmed)
+	}
+
+	if c.prompt != nil {
+		if err := c.prompt.PushToHistory(trimmed); err != nil {
+			log.Debug(err.Error())
+		}
+	}
+
+	results := c.impl.Handler.Execute(c.input)
+	if results == nil {
+		c.Close()
+		log.Infof("Connection closed")
+		os.Exit(0)
+	}
+	if err := c.impl.Format.print(results); err != nil {
+		log.Errorf("Unable to format output: %s", err)
+		log.Infof("Source results:\n%v", results)
+	}
+
+	c.input = ""
+	c.livePrefixEnabled = false
+}
+
+// title return console's title.
+func (c *Console) title() string {
+	return c.impl.Handler.Title()
+}
+
+// complete provide prompt suggestions.
+func (c *Console) complete(input prompt.Document) []prompt.Suggest {
+	if c.input == "" && c.internal != nil {
+		return c.internal.Complete(input)
+	}
+	return c.impl.Handler.Complete(input)
+}
+
+// setPrefix adjust console prefix string.
+func (c *Console) setPrefix() {
+	c.prefix = fmt.Sprintf("%s> ", c.title())
+
+	livePrefixIndent := len(c.title())
+	if livePrefixIndent > maxLivePrefixIndent {
+		livePrefixIndent = maxLivePrefixIndent
+	}
+
+	c.livePrefix = fmt.Sprintf("%s> ", strings.Repeat(" ", livePrefixIndent))
+}
+
+// getPromptOptions prepare option for prompt.
+func (c *Console) getPromptOptions() []prompt.Option {
+	options := []prompt.Option{
+		prompt.OptionTitle(c.title()),
+		prompt.OptionPrefix(c.prefix),
+		prompt.OptionLivePrefix(func() (string, bool) {
+			return c.livePrefix, c.livePrefixEnabled
+		}),
+
+		prompt.OptionSuggestionBGColor(prompt.DarkGray),
+		prompt.OptionPreviewSuggestionTextColor(prompt.DefaultColor),
+
+		prompt.OptionCompletionWordSeparator(tarantoolWordSeparators),
+
+		prompt.OptionAddASCIICodeBind(
+			// Move to one word left.
+			prompt.ASCIICodeBind{
+				ASCIICode: controlLeftBytes,
+				Fn:        prompt.GoLeftWord,
+			},
+			// Move to one word right.
+			prompt.ASCIICodeBind{
+				ASCIICode: controlRightBytes,
+				Fn:        prompt.GoRightWord,
+			},
+		),
+		// Interrupt current unfinished expression.
+		prompt.OptionAddKeyBind(
+			prompt.KeyBind{
+				Key: prompt.ControlC,
+				Fn: func(buf *prompt.Buffer) {
+					c.input = ""
+					c.livePrefixEnabled = false
+					fmt.Println("^C")
+				},
+			},
+		),
+
+		prompt.OptionDisableAutoHistory(),
+		prompt.OptionReverseSearch(),
+	}
+
+	if c.impl.History != nil {
+		options = append(options, prompt.OptionHistory(c.impl.History.Command()))
+	}
+
+	return options
+}

cli/console/format.go

@@ -0,0 +1,26 @@
+package console
+
+import "github.com/tarantool/tt/cli/formatter"
+
+type Format struct {
+	// Mode specify how to formatting result.
+	Mode formatter.Format
+	// Opts options for Format.
+	Opts formatter.Opts
+}
+
+func (f Format) print(HandlerResult) error {
+	// TODO: implement formatting and print results.
+	return nil
+}
+
+func DefaultConsoleFormat() Format {
+	return Format{
+		Mode: formatter.TableFormat,
+		Opts: formatter.Opts{
+			Graphics:       true,
+			ColumnWidthMax: 0,
+			TableDialect:   formatter.DefaultTableDialect,
+		},
+	}
+}

cli/console/handler.go

@@ -0,0 +1,28 @@
+package console
+
+import "github.com/tarantool/go-prompt"
+
+// HandlerResult structure of data records.
+// Map keys is names of columns. And map value is content of column.
+// TODO: Solve what need return to make easy apply Formatter.
+// Possible: can we make it return an interface with methods to be handled in Formatter?
+type HandlerResult map[string]any
+
+// Handler is a auxiliary abstraction to isolate the console from
+// the implementation of a particular instruction processor.
+type Handler interface {
+	// Title return name of instruction processor instance.
+	Title() string
+
+	// Validate the input string.
+	Validate(input string) bool
+
+	// Complete checks the input and return available variants to continue typing.
+	Complete(input prompt.Document) []prompt.Suggest
+
+	// Execute accept input to perform actions defined by client implementation.
+	Execute(input string) HandlerResult
+
+	// Stop notify handler to terminate execution and close any opened streams.
+	Stop() // Q: А нужно ли иметь такой метод?
+}

cli/console/history.go

@@ -0,0 +1,13 @@
+package console
+
+const (
+	DefaultHistoryFileName = ".tarantool_history"
+	DefaultHistoryLines    = 10000
+)
+
+type History interface {
+	Open(fileName string, maxCommands int) error
+	AppendCommand(input string)
+	Command() []string
+	Stop() // Q: А нужно ли иметь такой метод?
+}