compose/ecs/context.go

/*
   Copyright 2020 Docker, Inc.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package ecs

import (
	"context"
	"fmt"
	"os"
	"reflect"
	"strings"

	"github.com/AlecAivazis/survey/v2/terminal"
	"github.com/aws/aws-sdk-go/aws/awserr"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/defaults"
	"gopkg.in/ini.v1"

	"github.com/docker/api/context/store"
	"github.com/docker/api/prompt"
)

type contextCreateAWSHelper struct {
	user prompt.UI
}

func newContextCreateHelper() contextCreateAWSHelper {
	return contextCreateAWSHelper{
		user: prompt.User{},
	}
}

func (h contextCreateAWSHelper) createContextData(_ context.Context, opts ContextParams) (interface{}, string, error) {
	accessKey := opts.AwsID
	secretKey := opts.AwsSecret

	ecsCtx := store.EcsContext{
		Profile: opts.Profile,
		Region:  opts.Region,
	}

	if h.missingRequiredFlags(ecsCtx) {
		profilesList, err := h.getProfiles()
		if err != nil {
			return nil, "", err
		}
		// get profile
		_, ok := profilesList[ecsCtx.Profile]
		if !ok {
			profile, err := h.chooseProfile(profilesList)
			if err != nil {
				return nil, "", err
			}
			ecsCtx.Profile = profile
		}
		// set region
		region, err := h.chooseRegion(ecsCtx.Region, profilesList[ecsCtx.Profile])
		if err != nil {
			return nil, "", err
		}
		ecsCtx.Region = region

		accessKey, secretKey, err = h.askCredentials()
		if err != nil {
			return nil, "", err
		}
	}
	if accessKey != "" && secretKey != "" {
		if err := h.saveCredentials(ecsCtx.Profile, accessKey, secretKey); err != nil {
			return nil, "", err
		}
	}

	description := ecsCtx.Region
	if opts.Description != "" {
		description = fmt.Sprintf("%s (%s)", opts.Description, description)
	}

	return ecsCtx, description, nil
}

func (h contextCreateAWSHelper) missingRequiredFlags(ctx store.EcsContext) bool {
	if ctx.Profile == "" || ctx.Region == "" {
		return true
	}
	return false
}

func (h contextCreateAWSHelper) saveCredentials(profile string, accessKeyID string, secretAccessKey string) error {
	p := credentials.SharedCredentialsProvider{Profile: profile}
	_, err := p.Retrieve()
	if err == nil {
		return fmt.Errorf("credentials already exist")
	}

	if err.(awserr.Error).Code() == "SharedCredsLoad" && err.(awserr.Error).Message() == "failed to load shared credentials file" {
		_, err := os.Create(p.Filename)
		if err != nil {
			return err
		}
	}
	credIni, err := ini.Load(p.Filename)
	if err != nil {
		return err
	}
	section, err := credIni.NewSection(profile)
	if err != nil {
		return err
	}
	_, err = section.NewKey("aws_access_key_id", accessKeyID)
	if err != nil {
		return err
	}
	_, err = section.NewKey("aws_secret_access_key", secretAccessKey)
	if err != nil {
		return err
	}
	return credIni.SaveTo(p.Filename)
}

func (h contextCreateAWSHelper) getProfiles() (map[string]ini.Section, error) {
	profiles := map[string]ini.Section{"new profile": {}}
	credIni, err := ini.Load(defaults.SharedConfigFilename())
	if err != nil {
		return nil, err
	}
	for _, section := range credIni.Sections() {
		if strings.HasPrefix(section.Name(), "profile") {
			profiles[section.Name()[len("profile "):]] = *section
		}
	}
	return profiles, nil
}

func (h contextCreateAWSHelper) chooseProfile(section map[string]ini.Section) (string, error) {
	keys := reflect.ValueOf(section).MapKeys()
	profiles := make([]string, len(keys))
	for i := 0; i < len(keys); i++ {
		profiles[i] = keys[i].String()
	}

	selected, err := h.user.Select("Select AWS Profile", profiles)
	if err != nil {
		if err == terminal.InterruptErr {
			os.Exit(-1)
		}
		return "", err
	}
	profile := profiles[selected]
	if profiles[selected] == "new profile" {
		return h.user.Input("profile name", "")
	}
	return profile, nil
}

func (h contextCreateAWSHelper) chooseRegion(region string, section ini.Section) (string, error) {
	defaultRegion := region
	if defaultRegion == "" && section.Name() != "" {
		reg, err := section.GetKey("region")
		if err == nil {
			defaultRegion = reg.Value()
		}
	}
	result, err := h.user.Input("Region", defaultRegion)
	if err != nil {
		return "", err
	}
	return result, nil
}

func (h contextCreateAWSHelper) askCredentials() (string, string, error) {
	confirm, err := h.user.Confirm("Enter credentials", false)
	if err != nil {
		return "", "", err
	}
	if confirm {
		accessKeyID, err := h.user.Input("AWS Access Key ID", "")
		if err != nil {
			return "", "", err
		}
		secretAccessKey, err := h.user.Password("Enter AWS Secret Access Key")
		if err != nil {
			return "", "", err
		}
		// validate password
		if len(secretAccessKey) < 3 {
			return "", "", fmt.Errorf("AWS Secret Access Key must have more than 3 characters")
		}
		return accessKeyID, secretAccessKey, nil
	}
	return "", "", nil
}