connect: add initial custom evaler support

Add support for customizing the way user input is processed.
The `--evaler` option is added to specify the Lua code, which
accepts `cmd` var containing user input for current connection.
The evaler Lua code can be loaded from file.
Autocompletion is disabled if custom evaler is set.

CHANGELOG.md

@@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added
 
+- `tt connect`: add new `--evaler` option to support for customizing
+the way user input is processed.
+
 ### Changed
 
 ### Fixed

cli/cmd/connect.go

@@ -32,6 +32,7 @@ var (
 	connectSslCiphers  string
 	connectInteractive bool
 	connectBinary      bool
+	connectEvaler      string
 )
 
 // NewConnectCmd creates connect command.
@@ -102,6 +103,9 @@ func NewConnectCmd() *cobra.Command {
 		false, `enter interactive mode after executing 'FILE'`)
 	connectCmd.Flags().BoolVarP(&connectBinary, "binary", "",
 		false, `connect to instance using binary port`)
+	connectCmd.Flags().StringVar(&connectEvaler, "evaler", "",
+		`use the provided Lua expression as an interpreter for user's input of the connection`)
+	connectCmd.Flags().MarkHidden("evaler")
 
 	return connectCmd
 }
@@ -197,6 +201,7 @@ func internalConnectModule(cmdCtx *cmdcontext.CmdCtx, args []string) error {
 		SslCiphers:  connectSslCiphers,
 		Interactive: connectInteractive,
 		Binary:      connectBinary,
+		Evaler:      connectEvaler,
 	}
 
 	var ok bool

cli/codegen/generate_code.go

@@ -23,14 +23,6 @@ var luaCodeFiles = []generateLuaCodeOpts{
 			"checkSyntax": "cli/running/lua/check.lua",
 		},
 	},
-	{
-		PackageName: "connect",
-		FileName:    "cli/connect/lua_code_gen.go",
-		VariablesMap: map[string]string{
-			"evalFuncBody":           "cli/connect/lua/eval_func_body.lua",
-			"getSuggestionsFuncBody": "cli/connect/lua/get_suggestions_func_body.lua",
-		},
-	},
 	{
 		PackageName: "connector",
 		FileName:    "cli/connector/lua_code_gen.go",

cli/connect/connect.go

@@ -7,6 +7,7 @@ import (
 	"path"
 	"syscall"
 
+	"github.com/tarantool/tt/cli/connect/internal/luabody"
 	"github.com/tarantool/tt/cli/connector"
 	"github.com/tarantool/tt/cli/formatter"
 	"golang.org/x/crypto/ssh/terminal"
@@ -40,6 +41,8 @@ type ConnectCtx struct {
 	ConnectTarget string
 	// Binary port is used
 	Binary bool
+	// Evaler lua expression.
+	Evaler string
 }
 
 const (
@@ -114,7 +117,11 @@ func Eval(connectCtx ConnectCtx, connOpts connector.ConnectOpts, args []string)
 	}
 
 	// Execution of the command.
-	response, err := conn.Eval(evalFuncBody, evalArgs, connector.RequestOpts{})
+	evalBody, err := luabody.GetEvalFuncBody(connectCtx.Evaler)
+	if err != nil {
+		return nil, err
+	}
+	response, err := conn.Eval(evalBody, evalArgs, connector.RequestOpts{})
 	if err != nil {
 		return nil, err
 	}

cli/connect/console.go

@@ -16,6 +16,7 @@ import (
 	"gopkg.in/yaml.v2"
 
 	"github.com/tarantool/go-prompt"
+	"github.com/tarantool/tt/cli/connect/internal/luabody"
 	"github.com/tarantool/tt/cli/connector"
 	"github.com/tarantool/tt/cli/formatter"
 )
@@ -121,10 +122,13 @@ func NewConsole(connOpts connector.ConnectOpts, connectCtx ConnectCtx, title str
 	}
 
 	// Initialize user commands executor.
-	console.executor = getExecutor(console)
+	console.executor, err = getExecutor(console, connectCtx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to init prompt: %s", err)
+	}
 
 	// Initialize commands completer.
-	console.completer = getCompleter(console)
+	console.completer = getCompleter(console, connectCtx)
 
 	// Initialize syntax checkers.
 	luaValidator := NewLuaValidator()
@@ -182,8 +186,14 @@ func (console *Console) Close() {
 }
 
 // getExecutor returns command executor.
-func getExecutor(console *Console) func(string) {
+func getExecutor(console *Console, connectCtx ConnectCtx) (func(string), error) {
 	commandsExecutor := newCmdExecutor()
+
+	evalBody, err := luabody.GetEvalFuncBody(connectCtx.Evaler)
+	if err != nil {
+		return nil, err
+	}
+
 	executor := func(in string) {
 		if console.input == "" {
 			if commandsExecutor.Execute(console, in) {
@@ -237,7 +247,7 @@ func getExecutor(console *Console) func(string) {
 		}
 
 		var data string
-		if _, err := console.conn.Eval(evalFuncBody, args, opts); err != nil {
+		if _, err := console.conn.Eval(evalBody, args, opts); err != nil {
 			if err == io.EOF {
 				// We need to call 'console.Close()' here because in some cases (e.g 'os.exit()')
 				// it won't be called from 'defer console.Close' in 'connect.runConsole()'.
@@ -266,10 +276,16 @@ func getExecutor(console *Console) func(string) {
 		console.livePrefixEnabled = false
 	}
 
-	return executor
+	return executor, nil
 }
 
-func getCompleter(console *Console) prompt.Completer {
+func getCompleter(console *Console, connectCtx ConnectCtx) prompt.Completer {
+	if len(connectCtx.Evaler) != 0 {
+		return func(prompt.Document) []prompt.Suggest {
+			return nil
+		}
+	}
+
 	completer := func(in prompt.Document) []prompt.Suggest {
 		if len(in.Text) == 0 {
 			return nil
@@ -295,7 +311,7 @@ func getCompleter(console *Console) prompt.Completer {
 			ResData:     &suggestionsTexts,
 		}
 
-		if _, err := console.conn.Eval(getSuggestionsFuncBody, args, opts); err != nil {
+		if _, err := console.conn.Eval(luabody.GetSuggestionsFuncBody(), args, opts); err != nil {
 			return nil
 		}
 

cli/connect/internal/luabody/eval.go

@@ -0,0 +1,39 @@
+package luabody
+
+import (
+	_ "embed"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/tarantool/cartridge-cli/cli/templates"
+)
+
+//go:embed eval_func_body.lua
+var evalFuncBody string
+
+//go:embed get_suggestions_func_body.lua
+var getSuggestionsFuncBody string
+
+// GetEvalFuncBody returns lua code of eval func.
+func GetEvalFuncBody(evaler string) (string, error) {
+	mapping := map[string]string{}
+	if len(evaler) != 0 {
+		if strings.HasPrefix(evaler, "@") {
+			evalerFileBytes, err := os.ReadFile(strings.TrimPrefix(evaler, "@"))
+			if err != nil {
+				return "", fmt.Errorf("failed to read the evaler file: %s", err)
+			}
+			mapping["evaler"] = string(evalerFileBytes)
+		} else {
+			mapping["evaler"] = evaler
+		}
+	}
+
+	return templates.GetTemplatedStr(&evalFuncBody, mapping)
+}
+
+// GetEvalFuncBody returns lua code for completions.
+func GetSuggestionsFuncBody() string {
+	return getSuggestionsFuncBody
+}

cli/connect/lua/eval_func_body.lua → cli/connect/internal/luabody/eval_func_body.lua

@@ -13,13 +13,19 @@ if is_command(cmd) or is_sql_language == true then
     return require('console').eval(cmd)
 end
 
+{{ if .evaler }}
+local function fun()
+    {{ .evaler }}
+end
+{{ else }}
 local fun, errmsg = loadstring("return "..cmd)
 if not fun then
     fun, errmsg = loadstring(cmd)
 end
 if not fun then
     return yaml.encode({box.NULL})
 end
+{{ end }}
 
 local function table_pack(...)
     return {n = select('#', ...), ...}
@@ -44,7 +50,7 @@ if not ret[1] then
     if err == nil then
         err = box.NULL
     end
-    return yaml.encode({{error = err}})
+    return yaml.encode({ {error = err} })
 end
 if ret.n == 1 then
     return "---\n...\n"

cli/connect/language.go

@@ -6,6 +6,7 @@ import (
 
 	"gopkg.in/yaml.v2"
 
+	"github.com/tarantool/tt/cli/connect/internal/luabody"
 	"github.com/tarantool/tt/cli/connector"
 )
 
@@ -60,7 +61,11 @@ func ChangeLanguage(evaler connector.Evaler, lang Language) error {
 	}
 
 	languageCmd := setLanguagePrefix + " " + lang.String()
-	response, err := evaler.Eval(evalFuncBody,
+	evalBody, err := luabody.GetEvalFuncBody("")
+	if err != nil {
+		return err
+	}
+	response, err := evaler.Eval(evalBody,
 		[]interface{}{languageCmd},
 		connector.RequestOpts{},
 	)

cli/connect/language_test.go

@@ -6,7 +6,9 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
+	"github.com/tarantool/cartridge-cli/cli/templates"
 	. "github.com/tarantool/tt/cli/connect"
 	"github.com/tarantool/tt/cli/connector"
 )
@@ -83,11 +85,12 @@ func (evaler *inputEvaler) Eval(fun string,
 }
 
 func TestChangeLanguage_requestInputs(t *testing.T) {
-	rawFun, err := os.ReadFile("./lua/eval_func_body.lua")
-	if err != nil {
-		t.Fatal("Failed to read lua file:", err)
-	}
-	expectedFun := string(rawFun)
+	rawFun, err := os.ReadFile("./internal/luabody/eval_func_body.lua")
+	require.NoError(t, err, "Failed to read lua file")
+	rawFunStr := string(rawFun)
+	expectedFun, err := templates.GetTemplatedStr(&rawFunStr, map[string]string{})
+	require.NoError(t, err, "Failed to render eval func body template")
+
 	expectedOpts := connector.RequestOpts{}
 	cases := []struct {
 		lang Language

test/integration/connect/test_connect.py

@@ -1,3 +1,4 @@
+import itertools
 import os
 import platform
 import re
@@ -3088,3 +3089,87 @@ def test_set_delimiter(
     finally:
         # Stop the Instance.
         stop_app(tt_cmd, tmpdir, "test_app")
+
+
+def test_custom_evaler(tt_cmd, tmpdir_with_cfg):
+    skip_if_tuple_format_supported(tt_cmd, tmpdir_with_cfg)
+
+    tmpdir = tmpdir_with_cfg
+    test_app_path = os.path.join(os.path.dirname(__file__), "test_output_format_app",
+                                                            "test_app.lua")
+    copy_data(tmpdir, [test_app_path])
+    start_app(tt_cmd, tmpdir, "test_app")
+
+    expected_output = '''+---------+
+| name    |
++---------+
+| William |
++---------+
+'''
+    try:
+        file = wait_file(os.path.join(tmpdir, "test_app"), "ready", [])
+        assert file != ""
+
+        with open(os.path.join(tmpdir, "evaler.lua"), 'w') as f:
+            f.write("return box.execute(cmd)")
+
+        uris = ["localhost:3013", "tcp://localhost:3013"]
+        evalers = ["return box.execute(cmd)", os.path.join("@" + tmpdir, "evaler.lua")]
+        for uri, evaler in itertools.product(uris, evalers):
+            ret, output = try_execute_on_instance(
+                tt_cmd,
+                tmpdir,
+                uri,
+                stdin="SELECT name FROM customers WHERE id = 4",
+                opts={"--evaler": evaler,
+                      "-x": "table"},
+            )
+
+            assert ret
+            assert output == expected_output
+
+    finally:
+        stop_app(tt_cmd, tmpdir, "test_app")
+
+
+def test_custom_evaler_errors(tt_cmd, tmpdir_with_cfg):
+    tmpdir = tmpdir_with_cfg
+    test_app_path = os.path.join(os.path.dirname(__file__), "test_output_format_app",
+                                                            "test_app.lua")
+    copy_data(tmpdir, [test_app_path])
+    start_app(tt_cmd, tmpdir, "test_app")
+
+    try:
+        file = wait_file(os.path.join(tmpdir, "test_app"), "ready", [])
+        assert file != ""
+
+        with open(os.path.join(tmpdir, "evaler.lua"), 'w') as f:
+            f.write("return box.execute(cmd)")
+
+        uris = ["localhost:3013", "tcp://localhost:3013"]
+        for uri in uris:
+            ret, output = try_execute_on_instance(
+                tt_cmd,
+                tmpdir,
+                uri,
+                stdin="SELECT name FROM customers WHERE id = 4",
+                opts={"--evaler": "return box.execute(cmd"},
+            )
+
+            assert not ret
+            assert "Failed to execute command" in output
+
+        ret, output = try_execute_on_instance(
+            tt_cmd,
+            tmpdir,
+            "localhost:3013",
+            stdin="SELECT name FROM customers WHERE id = 4",
+            opts={"--evaler": "@missing_file"},
+        )
+
+        assert not ret
+        assert "failed to read the evaler file: open missing_file: " \
+               "no such file or directory" in output
+
+    finally:
+        stop_app(tt_cmd, tmpdir, "test_app")