/
sync_groups.go
171 lines (134 loc) · 3.86 KB
/
sync_groups.go
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package main
import (
"fmt"
"os"
"strings"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/service/iam"
"github.com/davidrjonas/ssh-iam-bridge/directory"
"github.com/davidrjonas/ssh-iam-bridge/strarray"
"github.com/davidrjonas/ssh-iam-bridge/unix"
)
type combinedGroup struct {
Sources []*iam.Group
Users []string
}
func removePrefix(s string, prefixes []string) (string, string) {
for _, prefix := range prefixes {
if strings.HasPrefix(s, prefix) {
return strings.TrimPrefix(s, prefix), prefix
}
}
return s, ""
}
func groupIDForGroups(groups []*iam.Group) int {
if len(groups) == 1 {
return awsToUnixID(groups[0].GroupId)
}
// Use the shortest group name as the group id
var minGroup *iam.Group
min := 9999
for _, group := range groups {
l := len(aws.StringValue(group.GroupName))
if l < min {
min = l
minGroup = group
}
}
return awsToUnixID(minGroup.GroupId)
}
func coalesceGroups(groups []*iam.Group, prefixes []string) map[string]combinedGroup {
combined := make(map[string]combinedGroup, 0)
for _, group := range groups {
users, err := directory.GetGroupUsers(group)
if err != nil {
fmt.Fprintf(os.Stderr, "Failed to get IAM group users for group %s (continuing), %s", aws.StringValue(group.GroupName), err)
continue
}
usernames := directory.UserNames(users)
name, _ := removePrefix(aws.StringValue(group.GroupName), prefixes)
if _, ok := combined[name]; ok {
cg := combined[name]
cg.Sources = append(cg.Sources, group)
cg.Users = strarray.Unique(append(cg.Users, usernames...))
} else {
combined[name] = combinedGroup{
Sources: []*iam.Group{group},
Users: usernames,
}
}
}
return combined
}
func isManagedUser(name string) bool {
return unix.UserID(name) >= uidOffset
}
func createUserFromName(name string) error {
user, err := directory.GetUser(name)
if err != nil {
return err
}
if err = unix.EnsureUser(name, awsToUnixID(user.UserId), "iam="+aws.StringValue(user.UserId)); err != nil {
return err
}
return nil
}
func ensureGroup(name string, gid int, users []string, ignoreMissingUsers bool) error {
if err := unix.EnsureGroup(name, gid); err != nil {
return err
}
systemUsers, err := unix.UsersInGroup(name)
if err != nil {
return err
}
if ignoreMissingUsers {
users = strarray.Filter(users, unix.UserExists)
} else {
missing := strarray.Filter(users, func(name string) bool { return !unix.UserExists(name) })
for _, username := range missing {
createUserFromName(username)
}
}
systemUsers = strarray.Filter(systemUsers, isManagedUser)
for _, username := range strarray.Diff(users, systemUsers) {
fmt.Println("Adding", username, "to group", name)
if err = unix.AddToGroup(name, username); err != nil {
fmt.Fprintf(os.Stderr, "Failed to add user '%s' to group '%s'; %s", username, name, err)
os.Exit(1)
}
}
for _, username := range strarray.Diff(systemUsers, users) {
fmt.Println("Removing", username, "from group", name)
if err = unix.RemoveFromGroup(name, username); err != nil {
fmt.Fprintf(os.Stderr, "Failed to remove user '%s' from group '%s'; %s", username, name, err)
os.Exit(1)
}
}
return nil
}
func syncGroups(prefix string) error {
return sync(prefix, true)
}
func sync(prefix string, ignoreMissingUsers bool) error {
role, err := directory.GetRole()
if err != nil {
fmt.Fprintf(os.Stderr, "Error getting IAM role (continuing), %s", err)
}
var prefixes []string
if role != "" {
prefixes = []string{prefix + role + "-", prefix}
} else {
prefixes = []string{prefix}
}
groups, err := directory.GetGroups(prefixes)
if err != nil {
return err
}
for name, cg := range coalesceGroups(groups, prefixes) {
if err := ensureGroup(name, groupIDForGroups(cg.Sources), cg.Users, ignoreMissingUsers); err != nil {
fmt.Fprintf(os.Stderr, "Failed to add group '%s'; %s", name, err)
os.Exit(1)
}
}
return nil
}