Refine flags (#16)

* Utilize go-flags's key-value-delimiter
* Print help when flag parsing is failed
* Make execution with --help be terminated successfly

cli.go

@@ -338,6 +338,9 @@ func (c *Cli) PrintProgressingMark() func() {
 	progressMarks := []string{`-`, `\`, `|`, `/`}
 	ticker := time.NewTicker(time.Millisecond * 100)
 	go func() {
+		// wait to avoid corruption with first output of command
+		<-ticker.C
+
 		i := 0
 		for {
 			<-ticker.C

go.mod

@@ -9,7 +9,7 @@ require (
 	cloud.google.com/go/spanner v1.62.0
 	github.com/cloudspannerecosystem/memefish v0.0.0-20241029131948-98b8bf288447
 	github.com/google/go-cmp v0.6.0
-	github.com/jessevdk/go-flags v1.4.0
+	github.com/jessevdk/go-flags v1.6.1
 	github.com/olekukonko/tablewriter v0.0.5
 	github.com/reeflective/readline v1.0.15
 	github.com/samber/lo v1.47.0

go.sum

@@ -828,6 +828,8 @@ github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/jessevdk/go-flags v1.4.0 h1:4IU2WS7AumrZ/40jfhf4QVDMsQwqA7VEHozFRrGARJA=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
+github.com/jessevdk/go-flags v1.6.1 h1:Cvu5U8UGrLay1rZfv/zP7iLpSHGUZ/Ou68T0iX1bBK4=
+github.com/jessevdk/go-flags v1.6.1/go.mod h1:Mk8T1hIAWpOiJiHa9rJASDK2UGWji0EuPGBnNLMooyc=
 github.com/jstemmer/go-junit-report v0.0.0-20190106144839-af01ea7f8024/go.mod h1:6v2b51hI/fHJwM22ozAgKL4VKDeJcHhJFhtBdhmNjmU=
 github.com/jstemmer/go-junit-report v0.9.1/go.mod h1:Brl9GWCQeLvo8nXZwPNNblvFj/XSXhF0NWZEnDohbsk=
 github.com/jung-kurt/gofpdf v1.0.0/go.mod h1:7Id9E/uU8ce6rXgefFLlgrJj/GYY22cpxn+r32jIOes=

main.go

@@ -20,39 +20,40 @@ package main
 import (
 	"fmt"
 	"io"
+	"maps"
 	"os"
 	"os/user"
 	"path/filepath"
 	"strings"
 
-	"github.com/samber/lo"
-
 	sppb "cloud.google.com/go/spanner/apiv1/spannerpb"
 	"github.com/jessevdk/go-flags"
+	"github.com/samber/lo"
+	"spheric.cloud/xiter"
 )
 
 type globalOptions struct {
 	Spanner spannerOptions `group:"spanner"`
 }
 
 type spannerOptions struct {
-	ProjectId    string   `short:"p" long:"project" env:"SPANNER_PROJECT_ID" description:"(required) GCP Project ID."`
-	InstanceId   string   `short:"i" long:"instance" env:"SPANNER_INSTANCE_ID" description:"(required) Cloud Spanner Instance ID"`
-	DatabaseId   string   `short:"d" long:"database" env:"SPANNER_DATABASE_ID" description:"(required) Cloud Spanner Database ID."`
-	Execute      string   `short:"e" long:"execute" description:"Execute SQL statement and quit. --sql is an alias."`
-	File         string   `short:"f" long:"file" description:"Execute SQL statement from file and quit."`
-	Table        bool     `short:"t" long:"table" description:"Display output in table format for batch mode."`
-	Verbose      bool     `short:"v" long:"verbose" description:"Display verbose output."`
-	Credential   string   `long:"credential" description:"Use the specific credential file"`
-	Prompt       string   `long:"prompt" description:"Set the prompt to the specified format"`
-	LogMemefish  bool     `long:"log-memefish" description:"Emit SQL parse log using memefish"`
-	HistoryFile  string   `long:"history" description:"Set the history file to the specified path"`
-	Priority     string   `long:"priority" description:"Set default request priority (HIGH|MEDIUM|LOW)"`
-	Role         string   `long:"role" description:"Use the specific database role"`
-	Endpoint     string   `long:"endpoint" description:"Set the Spanner API endpoint (host:port)"`
-	DirectedRead string   `long:"directed-read" description:"Directed read option (replica_location:replica_type). The replicat_type is optional and either READ_ONLY or READ_WRITE"`
-	SQL          string   `long:"sql" description:"alias of --execute" hidden:"true"`
-	Set          []string `long:"set" description:"Set system variables e.g. --set=name1=value1 --set=name2=value2"`
+	ProjectId    string            `long:"project" short:"p" env:"SPANNER_PROJECT_ID"  description:"(required) GCP Project ID."`
+	InstanceId   string            `long:"instance" short:"i" env:"SPANNER_INSTANCE_ID" description:"(required) Cloud Spanner Instance ID"`
+	DatabaseId   string            `long:"database" short:"d" env:"SPANNER_DATABASE_ID" description:"(required) Cloud Spanner Database ID."`
+	Execute      string            `long:"execute" short:"e" description:"Execute SQL statement and quit. --sql is an alias."`
+	File         string            `long:"file" short:"f" description:"Execute SQL statement from file and quit."`
+	Table        bool              `long:"table" short:"t" description:"Display output in table format for batch mode."`
+	Verbose      bool              `long:"verbose" short:"v" description:"Display verbose output."`
+	Credential   string            `long:"credential" description:"Use the specific credential file"`
+	Prompt       string            `long:"prompt" description:"Set the prompt to the specified format"`
+	LogMemefish  bool              `long:"log-memefish" description:"Emit SQL parse log using memefish"`
+	HistoryFile  string            `long:"history" description:"Set the history file to the specified path"`
+	Priority     string            `long:"priority" description:"Set default request priority (HIGH|MEDIUM|LOW)"`
+	Role         string            `long:"role" description:"Use the specific database role"`
+	Endpoint     string            `long:"endpoint" description:"Set the Spanner API endpoint (host:port)"`
+	DirectedRead string            `long:"directed-read" description:"Directed read option (replica_location:replica_type). The replicat_type is optional and either READ_ONLY or READ_WRITE"`
+	SQL          string            `long:"sql" hidden:"true" description:"alias of --execute"`
+	Set          map[string]string `long:"set" key-value-delimiter:"=" description:"Set system variables e.g. --set=name1=value1 --set=name2=value2"`
 }
 
 var logMemefish bool
@@ -65,24 +66,20 @@ func main() {
 	}
 
 	// then, process environment variables and command line options
-	// use another parser to process environment variable
-	if _, err := flags.NewParser(&gopts, flags.Default).Parse(); err != nil {
+	// use another parser to process environment variables with higher precedence than configuration files
+	flagParser := flags.NewParser(&gopts, flags.Default)
+	if _, err := flagParser.Parse(); flags.WroteHelp(err) {
+		// exit successfully
+		return
+	} else if err != nil {
+		flags.NewParser(&gopts, flags.Default).WriteHelp(os.Stderr)
 		exitf("Invalid options\n")
 	}
 
 	opts := gopts.Spanner
 
 	var sysVars systemVariables
 
-	sets := make(map[string]string)
-	for _, s := range opts.Set {
-		k, v, ok := strings.Cut(s, "=")
-		if !ok {
-			exitf("invalid system variable %v\n", s)
-		}
-		sets[strings.ToUpper(k)] = v
-	}
-
 	logMemefish = opts.LogMemefish
 
 	if opts.ProjectId == "" || opts.InstanceId == "" || opts.DatabaseId == "" {
@@ -127,6 +124,8 @@ func main() {
 		}
 	}
 
+	sets := maps.Collect(xiter.MapKeys(maps.All(opts.Set), strings.ToUpper))
+
 	for k, v := range sets {
 		if err := sysVars.Set(k, v); err != nil {
 			exitf("failed to set system variable. name: %v, value: %v, err: %v\n", k, v, err)