gsuite.go

package main

import (
	"fmt"
	"io/ioutil"

	"golang.org/x/net/context"
	"golang.org/x/oauth2/google"

	"encoding/json"
	admin "google.golang.org/api/admin/directory/v1"
	"google.golang.org/api/option"
	"strings"
)

// RsaKey struct to map json RawMessage to
type RsaKey struct {
	Key string `json:"Public_SSH_Key"`
}

// CreateDirectoryService builds and returns an Admin SDK Directory service
// object authorized with the service accounts that act on behalf of the
// given user.
func CreateDirectoryService(
	userEmail string,
	credentialsPath string,
) (*admin.Service, error) {
	ctx := context.Background()

	jsonCredentials, err := ioutil.ReadFile(credentialsPath)
	if err != nil {
		return nil, err
	}

	config, err := google.JWTConfigFromJSON(
		jsonCredentials,
		admin.AdminDirectoryUserScope,
	)
	if err != nil {
		return nil, fmt.Errorf("JWTConfigFromJSON: %v", err)
	}
	config.Subject = userEmail

	ts := config.TokenSource(ctx)

	srv, err := admin.NewService(ctx, option.WithTokenSource(ts))
	if err != nil {
		return nil, fmt.Errorf("NewService: %v", err)
	}
	return srv, nil
}

// PullGsuiteUsers Creates a Google Workspace API Directory Service and
// authenticates. It then queries the API for a list of domain users with
// the appropriate custom attribute set. Returns a list of gsuiteUser objects.
func PullGsuiteUsers(
	email string,
	domain string,
	mask string,
	credentialsPath string,
) ([]IAMUser, error) {
	// gsuiteUsers List of gsuiteUser objects
	var gsuiteUsers = []IAMUser{}

	srv, e := CreateDirectoryService(email, credentialsPath)
	if e != nil {
		return nil, e
	}
	r, err := srv.Users.List().Domain(domain).Projection(
		"Custom",
	).CustomFieldMask(mask).Do()
	if err != nil {
		return nil, err
	}

	if len(r.Users) != 0 {
		for _, u := range r.Users {
			if val, ok := u.CustomSchemas["SSHKEY"]; ok {
				// Custom Schema SSHKEY exists

				var rsakey RsaKey
				err := json.Unmarshal(val, &rsakey)
				if err != nil {
					return nil, err
				}

				uName := u.Name.GivenName + "." + u.Name.FamilyName
				gUser := IAMUser{
					username:  strings.ToLower(uName),
					publickey: rsakey.Key,
				}
				gsuiteUsers = append(gsuiteUsers, gUser)
			}
		}
	}
	return gsuiteUsers, nil
}