github.com/Schaudge/grailbase@v0.0.0-20240223061707-44c758a471c0/config/flag_test.go

// Copyright 2019 GRAIL, Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.

package config

import (
	"errors"
	"flag"
	"fmt"
	"os"
	"runtime"
	"strconv"
	"testing"

	"github.com/Schaudge/grailbase/must"
)

// This test uses a mock "app" to demonstrate various aspects of package config.

type credentials interface {
	Creds() string
}

type userCredentials string

func (u userCredentials) Creds() string { return string(u) }

type envCredentials struct{}

func (e envCredentials) Creds() string { return "environment" }

type database struct {
	table string
	creds credentials
}

type frontend struct {
	db    database
	creds credentials
	limit int
}

func init() {
	Register("app/auth/env", func(constr *Constructor[envCredentials]) {
		constr.New = func() (envCredentials, error) {
			return envCredentials{}, nil
		}
	})
	Register("app/auth/login", func(constr *Constructor[userCredentials]) {
		var (
			username = constr.String("user", "test", "the username")
			password = constr.String("password", "secret", "the password")
		)
		constr.New = func() (userCredentials, error) {
			return userCredentials(fmt.Sprintf("%s:%s", *username, *password)), nil
		}
	})

	Register("app/database", func(constr *Constructor[database]) {
		var db database
		constr.StringVar(&db.table, "table", "defaulttable", "the database table")
		constr.InstanceVar(&db.creds, "credentials", "app/auth/env", "credentials used for database access")
		constr.New = func() (database, error) {
			if db.creds == nil {
				return database{}, errors.New("credentials not defined")
			}
			return db, nil
		}
	})

	Register("app/frontend", func(constr *Constructor[frontend]) {
		var fe frontend
		constr.InstanceVar(&fe.db, "database", "app/database", "the database to be used")
		constr.InstanceVar(&fe.creds, "credentials", "app/auth/env", "credentials to use for authentication")
		constr.IntVar(&fe.limit, "limit", 128, "maximum number of concurrent requests to handle")
		constr.New = func() (frontend, error) {
			if fe.db == (database{}) || fe.creds == nil {
				return frontend{}, errors.New("missing configuration")
			}
			return fe, nil
		}
	})
}

func TestFlag(t *testing.T) {
	profile := func(args ...string) *Profile {
		t.Helper()
		p := New()
		f, err := os.Open("testdata/profile")
		must.Nil(err)
		defer f.Close()
		if err := p.Parse(f); err != nil {
			t.Fatal(err)
		}
		fs := flag.NewFlagSet("test", flag.PanicOnError)
		p.RegisterFlags(fs, "", "testdata/profile")
		if err := fs.Parse(args); err != nil {
			t.Fatal(err)
		}
		if err := p.ProcessFlags(); err != nil {
			t.Fatal(err)
		}
		return p
	}

	for _, test := range []struct {
		line           int
		args           []string
		wantFE, wantDB string
	}{
		{
			callerLine(),
			nil,
			"marius:supersecret", "marius:supersecret",
		},
		{
			callerLine(),
			[]string{"-set", "app/auth/login.password=public"},
			"marius:public", "marius:public",
		},
		{
			callerLine(),
			[]string{"-set", "app/frontend.credentials=app/auth/env"},
			"environment", "marius:supersecret",
		},
		{
			callerLine(),
			[]string{"-profileinline", `param app/auth/login password = "public"`},
			"marius:public", "marius:public",
		},
		{
			callerLine(),
			[]string{
				"-set", "app/auth/login.password=public",
				"-profile", "testdata/profile",
			},
			// Parameter settings in profile file should override, since they come later.
			"marius:supersecret", "marius:supersecret",
		},
		{
			callerLine(),
			[]string{
				"-set", "app/auth/login.password=public",
				"-profile", "testdata/profile",
				"-set", "app/auth/login.password=hunter2",
			},
			"marius:hunter2", "marius:hunter2",
		},
		{
			callerLine(),
			[]string{
				"-set", "app/auth/login.password=public",
				"-profile", "testdata/profile",
				"-set", "app/auth/login.password=hunter2",
				"-profileinline", `
					instance test/felogin app/auth/login (
						user = "tester"
					)
					param app/frontend credentials = test/felogin
				`,
			},
			"tester:hunter2", "marius:hunter2",
		},
		{
			callerLine(),
			[]string{
				"-set", "app/auth/login.password=public",
				"-profile", "testdata/profile",
				"-set", "app/auth/login.password=hunter2",
				"-profileinline", `
					instance test/felogin app/auth/login (
						user = "tester"
					)
					param app/frontend credentials = test/felogin
					param test/felogin password = "abc"
				`,
			},
			"tester:abc", "marius:hunter2",
		},
		{
			callerLine(),
			[]string{
				"-set", "app/auth/login.password=public",
				"-profile", "testdata/profile",
				"-set", "app/auth/login.password=hunter2",
				"-profileinline", `
					instance test/felogin app/auth/login (
						user = "tester"
					)
					param app/frontend credentials = test/felogin
				`,
				"-profile", "testdata/profile_felogin_password",
			},
			"tester:abc", "marius:hunter2",
		},
	} {
		t.Run(strconv.Itoa(test.line), func(t *testing.T) {
			p := profile(test.args...)
			var fe frontend
			if err := p.Instance("app/frontend", &fe); err != nil {
				t.Fatal(err)
			}
			if got, want := fe.creds.Creds(), test.wantFE; got != want {
				t.Errorf("got %v, want %v", got, want)
			}
			if got, want := fe.db.creds.Creds(), test.wantDB; got != want {
				t.Errorf("got %v, want %v", got, want)
			}
		})
	}
}

func callerLine() int {
	_, _, line, _ := runtime.Caller(1) // 1 skips the callerLine() frame.
	return line
}