rclone/fs/backend_config.go
Nick Craig-Wood 095cf9e4be config create: add --non-interactive and --continue parameters #3455
This adds a mechanism to add external interfaces to rclone using the
state based configuration.
2021-05-14 14:07:44 +01:00

339 lines
10 KiB
Go

// Structures and utilities for backend config
//
//
package fs
import (
"context"
"fmt"
"strings"
"github.com/pkg/errors"
"github.com/rclone/rclone/fs/config/configmap"
)
const (
// ConfigToken is the key used to store the token under
ConfigToken = "token"
)
// ConfigOAuth should be called to do the OAuth
//
// set in lib/oauthutil to avoid a circular import
var ConfigOAuth func(ctx context.Context, name string, m configmap.Mapper, ri *RegInfo, in ConfigIn) (*ConfigOut, error)
// ConfigIn is passed to the Config function for an Fs
//
// The interactive config system for backends is state based. This is
// so that different frontends to the config can be attached, eg over
// the API or web page.
//
// Each call to the config system supplies ConfigIn which tells the
// system what to do. Each will return a ConfigOut which gives a
// question to ask the user and a state to return to. There is one
// special question which allows the backends to do OAuth.
//
// The ConfigIn contains a State which the backend should act upon and
// a Result from the previous question to the user.
//
// If ConfigOut is nil or ConfigOut.State == "" then the process is
// deemed to have finished. If there is no Option in ConfigOut then
// the next state will be called immediately. This is wrapped in
// ConfigGoto and ConfigResult.
//
// Backends should keep no state in memory - if they need to persist
// things between calls it should be persisted in the config file.
// Things can also be persisted in the state using the StatePush and
// StatePop utilities here.
//
// The utilities here are convenience methods for different kinds of
// questions and responses.
//
// Where the questions ask for a name then this should start with
// "config_" to show it is an ephemeral config input rather than the
// actual value stored in the config file.
type ConfigIn struct {
State string // State to run
Result string // Result from previous Option
}
// ConfigOut is returned from Config function for an Fs
//
// State is the state for the next call to Config
// OAuth is a special value set by oauthutil.ConfigOAuth
// Error is displayed to the user before asking a question
// Result is passed to the next call to Config if Option/OAuth isn't set
type ConfigOut struct {
State string // State to jump to after this
Option *Option // Option to query user about
OAuth interface{} `json:"-"` // Do OAuth if set
Error string // error to be displayed to the user
Result string // if Option/OAuth not set then this is passed to the next state
}
// ConfigInputOptional asks the user for a string which may be empty
//
// state should be the next state required
// name is the config name for this item
// help should be the help shown to the user
func ConfigInputOptional(state string, name string, help string) (*ConfigOut, error) {
return &ConfigOut{
State: state,
Option: &Option{
Name: name,
Help: help,
Default: "",
},
}, nil
}
// ConfigInput asks the user for a non-empty string
//
// state should be the next state required
// name is the config name for this item
// help should be the help shown to the user
func ConfigInput(state string, name string, help string) (*ConfigOut, error) {
out, _ := ConfigInputOptional(state, name, help)
out.Option.Required = true
return out, nil
}
// ConfigPassword asks the user for a password
//
// state should be the next state required
// name is the config name for this item
// help should be the help shown to the user
func ConfigPassword(state string, name string, help string) (*ConfigOut, error) {
out, _ := ConfigInputOptional(state, name, help)
out.Option.IsPassword = true
return out, nil
}
// ConfigGoto goes to the next state with empty Result
//
// state should be the next state required
func ConfigGoto(state string) (*ConfigOut, error) {
return &ConfigOut{
State: state,
}, nil
}
// ConfigResult goes to the next state with result given
//
// state should be the next state required
// result should be the result for the next state
func ConfigResult(state, result string) (*ConfigOut, error) {
return &ConfigOut{
State: state,
Result: result,
}, nil
}
// ConfigError shows the error to the user and goes to the state passed in
//
// state should be the next state required
// Error should be the error shown to the user
func ConfigError(state string, Error string) (*ConfigOut, error) {
return &ConfigOut{
State: state,
Error: Error,
}, nil
}
// ConfigConfirm returns a ConfigOut structure which asks a Yes/No question
//
// state should be the next state required
// Default should be the default state
// name is the config name for this item
// help should be the help shown to the user
func ConfigConfirm(state string, Default bool, name string, help string) (*ConfigOut, error) {
return &ConfigOut{
State: state,
Option: &Option{
Name: name,
Help: help,
Default: Default,
Examples: []OptionExample{{
Value: "true",
Help: "Yes",
}, {
Value: "false",
Help: "No",
}},
},
}, nil
}
// ConfigChooseFixed returns a ConfigOut structure which has a list of items to choose from.
//
// state should be the next state required
// name is the config name for this item
// help should be the help shown to the user
// items should be the items in the list
//
// It chooses the first item to be the default.
// If there are no items then it will return an error.
// If there is only one item it will short cut to the next state
func ConfigChooseFixed(state string, name string, help string, items []OptionExample) (*ConfigOut, error) {
if len(items) == 0 {
return nil, errors.Errorf("no items found in: %s", help)
}
choose := &ConfigOut{
State: state,
Option: &Option{
Name: name,
Help: help,
Examples: items,
},
}
choose.Option.Default = choose.Option.Examples[0].Value
if len(items) == 1 {
// short circuit asking the question if only one entry
choose.Result = choose.Option.Examples[0].Value
choose.Option = nil
}
return choose, nil
}
// ConfigChoose returns a ConfigOut structure which has a list of items to choose from.
//
// state should be the next state required
// name is the config name for this item
// help should be the help shown to the user
// n should be the number of items in the list
// getItem should return the items (value, help)
//
// It chooses the first item to be the default.
// If there are no items then it will return an error.
// If there is only one item it will short cut to the next state
func ConfigChoose(state string, name string, help string, n int, getItem func(i int) (itemValue string, itemHelp string)) (*ConfigOut, error) {
items := make(OptionExamples, n)
for i := range items {
items[i].Value, items[i].Help = getItem(i)
}
return ConfigChooseFixed(state, name, help, items)
}
// StatePush pushes a new values onto the front of the config string
func StatePush(state string, values ...string) string {
for i := range values {
values[i] = strings.Replace(values[i], ",", ",", -1) // replace comma with unicode wide version
}
if state != "" {
values = append(values[:len(values):len(values)], state)
}
return strings.Join(values, ",")
}
type configOAuthKeyType struct{}
// OAuth key for config
var configOAuthKey = configOAuthKeyType{}
// ConfigOAuthOnly marks the ctx so that the Config will stop after
// finding an OAuth
func ConfigOAuthOnly(ctx context.Context) context.Context {
return context.WithValue(ctx, configOAuthKey, struct{}{})
}
// Return true if ctx is marked as ConfigOAuthOnly
func isConfigOAuthOnly(ctx context.Context) bool {
return ctx.Value(configOAuthKey) != nil
}
// StatePop pops a state from the front of the config string
// It returns the new state and the value popped
func StatePop(state string) (newState string, value string) {
comma := strings.IndexRune(state, ',')
if comma < 0 {
return "", state
}
value, newState = state[:comma], state[comma+1:]
value = strings.Replace(value, ",", ",", -1) // replace unicode wide comma with comma
return newState, value
}
// BackendConfig calls the config for the backend in ri
//
// It wraps any OAuth transactions as necessary so only straight forward config questions are emitted
func BackendConfig(ctx context.Context, name string, m configmap.Mapper, ri *RegInfo, in ConfigIn) (out *ConfigOut, err error) {
for {
out, err = backendConfigStep(ctx, name, m, ri, in)
if err != nil {
break
}
if out == nil || out.State == "" {
// finished
break
}
if out.Option != nil {
// question to ask user
break
}
if out.Error != "" {
// error to show user
break
}
// non terminal state, but no question to ask or error to show - loop here
in = ConfigIn{
State: out.State,
Result: out.Result,
}
}
return out, err
}
func backendConfigStep(ctx context.Context, name string, m configmap.Mapper, ri *RegInfo, in ConfigIn) (out *ConfigOut, err error) {
ci := GetConfig(ctx)
if ri.Config == nil {
return nil, nil
}
Debugf(name, "config in: state=%q, result=%q", in.State, in.Result)
defer func() {
Debugf(name, "config out: out=%+v, err=%v", out, err)
}()
switch {
case strings.HasPrefix(in.State, "*oauth"):
// Do internal oauth states
out, err = ConfigOAuth(ctx, name, m, ri, in)
case strings.HasPrefix(in.State, "*"):
err = errors.Errorf("unknown internal state %q", in.State)
default:
// Otherwise pass to backend
out, err = ri.Config(ctx, name, m, in)
}
if err != nil {
return nil, err
}
switch {
case out == nil:
case out.OAuth != nil:
// If this is an OAuth state the deal with it here
returnState := out.State
// If rclone authorize, stop after doing oauth
if isConfigOAuthOnly(ctx) {
Debugf(nil, "OAuth only is set - overriding return state")
returnState = ""
}
// Run internal state, saving the input so we can recall the state
return ConfigGoto(StatePush("", "*oauth", returnState, in.State, in.Result))
case out.Option != nil:
if out.Option.Name == "" {
return nil, errors.New("internal error: no name set in Option")
}
// If override value is set in the config then use that
if result, ok := m.Get(out.Option.Name); ok {
Debugf(nil, "Override value found, choosing value %q for state %q", result, out.State)
return ConfigResult(out.State, result)
}
// If AutoConfirm is set, choose the default value
if ci.AutoConfirm {
result := fmt.Sprint(out.Option.Default)
Debugf(nil, "Auto confirm is set, choosing default %q for state %q, override by setting config parameter %q", result, out.State, out.Option.Name)
return ConfigResult(out.State, result)
}
}
return out, nil
}