cli: adds new sql shell metacommands

- adds support for `\l`, `\dt`, `\du`, and ‘\d <table>`
- tweak welcome message for consistency
- fix welcome message to show `\q` instead of `CTRL + D` since that doesn’t work on Windows, and isn’t the primary documented way to quit from the shell

Release note: added \d, \dt, \du, \l metacommands to cli shell

pkg/cli/interactive_tests/test_version_reporting.tcl → pkg/cli/interactive_tests/test_sql_version_reporting.tcl

@@ -7,7 +7,7 @@ start_server $argv
 spawn $argv sql
 
 start_test "Check that the client starts with the welcome message."
-eexpect "# Welcome to the cockroach SQL interface."
+eexpect "# Welcome to the CockroachDB SQL shell."
 end_test
 
 start_test "Check that the client reports the server version, and correctly detects the version is the same as the client."

pkg/cli/sql.go

@@ -42,17 +42,36 @@ import (
 )
 
 const (
-	infoMessage = `# Welcome to the cockroach SQL interface.
+	welcomeMessage = `#
+# Welcome to the CockroachDB SQL shell.
 # All statements must be terminated by a semicolon.
-# To exit: CTRL + D.
+# To exit, type: \q.
 #
 `
-)
+	helpMessageFmt = `You are using 'cockroach sql', CockroachDB's lightweight SQL client.
+Type:
+  \? or "help"      print this help.
+  \q, quit, exit    exit the shell (Ctrl+C/Ctrl+D also supported)
+  \! CMD            run an external command and print its results on standard output.
+  \| CMD            run an external command and run its output as SQL statements.
+  \set [NAME]       set a client-side flag or (without argument) print the current settings.
+  \unset NAME       unset a flag.
+  \show             during a multi-line statement or transaction, show the SQL entered so far.
+  \h [NAME]         help on syntax of SQL commands.
+  \hf [NAME]        help on SQL built-in functions.
+  \l                list all databases in the CockroachDB cluster
+  \dt               show the tables of the current schema in the current database
+  \du               list the users for all databases
+  \d TABLE          show details about columns in the specified table
+More documentation about our SQL dialect and the CLI shell is available online:
+%s
+%s`
 
-const defaultPromptPattern = "%n@%M/%/%x>"
+	defaultPromptPattern = "%n@%M/%/%x>"
 
-// debugPromptPattern avoids substitution patterns that require a db roundtrip.
-const debugPromptPattern = "%n@%M>"
+	// debugPromptPattern avoids substitution patterns that require a db roundtrip.
+	debugPromptPattern = "%n@%M>"
+)
 
 // sqlShellCmd opens a sql shell.
 var sqlShellCmd = &cobra.Command{
@@ -187,21 +206,7 @@ const (
 
 // printCliHelp prints a short inline help about the CLI.
 func printCliHelp() {
-	fmt.Printf(`You are using 'cockroach sql', CockroachDB's lightweight SQL client.
-Type:
-  \q, quit, exit    exit the shell (Ctrl+C/Ctrl+D also supported)
-  \! CMD            run an external command and print its results on standard output.
-  \| CMD            run an external command and run its output as SQL statements.
-  \set [NAME]       set a client-side flag or (without argument) print the current settings.
-  \unset NAME       unset a flag.
-  \show             during a multi-line statement or transaction, show the SQL entered so far.
-  \? or "help"      print this help.
-  \h [NAME]         help on syntax of SQL commands.
-  \hf [NAME]        help on SQL built-in functions.
-
-More documentation about our SQL dialect and the CLI shell is available online:
-%s
-%s`,
+	fmt.Printf(helpMessageFmt,
 		base.DocsURL("sql-statements.html"),
 		base.DocsURL("use-the-built-in-sql-client.html"),
 	)
@@ -214,8 +219,7 @@ func (c *cliState) hasEditor() bool {
 	return c.ins != noLineEditor
 }
 
-// addHistory persists a line of input to the readline history
-// file.
+// addHistory persists a line of input to the readline history file.
 func (c *cliState) addHistory(line string) {
 	if !c.hasEditor() || len(line) == 0 {
 		return
@@ -1020,6 +1024,25 @@ func (c *cliState) doHandleCliCmd(loopState, nextState cliStateEnum) cliStateEnu
 	case `\hf`:
 		return c.handleFunctionHelp(cmd[1:], loopState, errState)
 
+	case `\l`:
+		c.concatLines = `SHOW DATABASES`
+		return cliRunStatement
+
+	case `\dt`:
+		c.concatLines = `SHOW TABLES`
+		return cliRunStatement
+
+	case `\du`:
+		c.concatLines = `SHOW USERS`
+		return cliRunStatement
+
+	case `\d`:
+		if len(cmd) == 2 {
+			c.concatLines = `SHOW COLUMNS FROM ` + cmd[1]
+			return cliRunStatement
+		}
+		return c.invalidSyntax(errState, `%s. Try \? for help.`, c.lastInputLine)
+
 	default:
 		if strings.HasPrefix(cmd[0], `\d`) {
 			// Unrecognized command for now, but we want to be helpful.
@@ -1408,8 +1431,8 @@ func runTerm(cmd *cobra.Command, args []string) error {
 	checkInteractive()
 
 	if cliCtx.isInteractive {
-		// The user only gets to see the info screen on interactive sessions.
-		fmt.Print(infoMessage)
+		// The user only gets to see the welcome message on interactive sessions.
+		fmt.Print(welcomeMessage)
 	}
 
 	conn, err := getPasswordAndMakeSQLClient("cockroach sql")

pkg/cli/sql_test.go

@@ -19,6 +19,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/security"
 	"github.com/cockroachdb/cockroach/pkg/sql/parser"
 	"github.com/cockroachdb/cockroach/pkg/util/leaktest"
+	"github.com/stretchr/testify/assert"
 )
 
 // Example_sql_lex tests the usage of the lexer in the sql subcommand.
@@ -188,3 +189,49 @@ func TestIsEndOfStatement(t *testing.T) {
 		}
 	}
 }
+
+// Test handleCliCmd cases for metacommands that are aliases for sql statements
+func TestHandleCliCmdSqlAliasMetacommands(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+	metaCommandTestsTable := []struct {
+		commandString string
+		wantSQLStmt   string
+	}{
+		{`\l`, `SHOW DATABASES`},
+		{`\dt`, `SHOW TABLES`},
+		{`\du`, `SHOW USERS`},
+		{`\d mytable`, `SHOW COLUMNS FROM mytable`},
+	}
+
+	var c cliState
+	for _, tt := range metaCommandTestsTable {
+		c = setupTestCliState()
+		c.lastInputLine = tt.commandString
+		gotState := c.doHandleCliCmd(cliStateEnum(0), cliStateEnum(1))
+
+		assert.Equal(t, cliRunStatement, gotState)
+		assert.Equal(t, tt.wantSQLStmt, c.concatLines)
+	}
+}
+
+func TestHandleCliCmdSlashDInvalidSyntax(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+
+	metaCommandTestsTable := []string{`\d`, `\d goodarg badarg`, `\dz`}
+
+	var c cliState
+	for _, tt := range metaCommandTestsTable {
+		c = setupTestCliState()
+		c.lastInputLine = tt
+		gotState := c.doHandleCliCmd(cliStateEnum(0), cliStateEnum(1))
+
+		assert.Equal(t, cliStateEnum(0), gotState)
+		assert.Equal(t, errInvalidSyntax, c.exitErr)
+	}
+}
+
+func setupTestCliState() cliState {
+	c := cliState{}
+	c.ins = noLineEditor
+	return c
+}