Modern POSIX style CLI for SQLCMD

.gitignore

@@ -1,5 +1,4 @@
 # Binaries for programs and plugins
-output
 *.exe
 *.exe~
 *.dll

cmd/cmd.go

@@ -0,0 +1,79 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+package cmd
+
+import (
+	"github.com/microsoft/go-sqlcmd/cmd/root"
+	"github.com/microsoft/go-sqlcmd/internal"
+	"github.com/microsoft/go-sqlcmd/internal/cmdparser"
+	"github.com/microsoft/go-sqlcmd/internal/config"
+	"github.com/microsoft/go-sqlcmd/internal/output"
+)
+
+var loggingLevel int
+var outputType string
+var configFilename string
+var rootCmd cmdparser.Command
+
+// Initialize initializes the command-line interface. The func passed into
+// cmdparser.Initialize is called after the command-line from the user has been
+// parsed, so the helpers are initialized with the values from the command-line
+// like '-v 4' which sets the logging level to maximum etc.
+func Initialize() {
+	cmdparser.Initialize(initialize)
+	rootCmd = cmdparser.New[*Root](root.SubCommands()...)
+}
+
+func initialize() {
+	options := internal.InitializeOptions{
+		ErrorHandler: checkErr,
+		HintHandler:  displayHints,
+		OutputType:   "yaml",
+		LoggingLevel: 2,
+	}
+
+	config.SetFileName(configFilename)
+	config.Load()
+	internal.Initialize(options)
+}
+
+// Execute runs the application based on the command-line
+// parameters the user has passed in.
+func Execute() {
+	rootCmd.Execute()
+}
+
+// IsValidSubCommand is TEMPORARY code, that will be removed when
+// we enable the new cobra based CLI by default.  It returns true if the
+// command-line provided by the user indicates they want the new cobra
+// based CLI, e.g. sqlcmd install, or sqlcmd query, or sqlcmd --help etc.
+func IsValidSubCommand(command string) bool {
+	return rootCmd.IsSubCommand(command)
+}
+
+// checkErr uses Cobra to check err, and halts the application if err is not
+// nil.  Pass (inject) checkErr into all dependencies (helpers etc.) as an
+// errorHandler.
+//
+// To aid debugging issues, if the logging level is > 2 (e.g. -v 3 or -4), we
+// panic which outputs a stacktrace.
+func checkErr(err error) {
+	if loggingLevel > 2 {
+		if err != nil {
+			panic(err)
+		}
+	}
+	rootCmd.CheckErr(err)
+}
+
+// displayHints displays helpful information on what the user should do next
+// to make progress.  displayHints is injected into dependencies (helpers etc.)
+func displayHints(hints []string) {
+	if len(hints) > 0 {
+		output.Infof("\nHINT:")
+		for i, hint := range hints {
+			output.Infof("  %d. %v", i+1, hint)
+		}
+	}
+}