terraform/backend/remote-state/inmem/backend.go

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package inmem
import (
"context"
"errors"
"fmt"
"sort"
"sync"
"time"
"github.com/hashicorp/terraform/backend"
"github.com/hashicorp/terraform/internal/legacy/helper/schema"
statespkg "github.com/hashicorp/terraform/states"
"github.com/hashicorp/terraform/states/remote"
"github.com/hashicorp/terraform/states/statemgr"
)
// we keep the states and locks in package-level variables, so that they can be
// accessed from multiple instances of the backend. This better emulates
// backend instances accessing a single remote data store.
var (
states stateMap
locks lockMap
)
func init() {
Reset()
}
// Reset clears out all existing state and lock data.
// This is used to initialize the package during init, as well as between
// tests.
func Reset() {
states = stateMap{
m: map[string]*remote.State{},
}
locks = lockMap{
m: map[string]*statemgr.LockInfo{},
}
}
// New creates a new backend for Inmem remote state.
func New() backend.Backend {
// Set the schema
s := &schema.Backend{
Schema: map[string]*schema.Schema{
"lock_id": &schema.Schema{
Type: schema.TypeString,
Optional: true,
Description: "initializes the state in a locked configuration",
},
},
}
backend := &Backend{Backend: s}
backend.Backend.ConfigureFunc = backend.configure
return backend
}
type Backend struct {
*schema.Backend
}
func (b *Backend) configure(ctx context.Context) error {
states.Lock()
defer states.Unlock()
defaultClient := &RemoteClient{
Name: backend.DefaultStateName,
}
states.m[backend.DefaultStateName] = &remote.State{
Client: defaultClient,
}
// set the default client lock info per the test config
data := schema.FromContextBackendConfig(ctx)
if v, ok := data.GetOk("lock_id"); ok && v.(string) != "" {
info := statemgr.NewLockInfo()
info.ID = v.(string)
info.Operation = "test"
info.Info = "test config"
locks.lock(backend.DefaultStateName, info)
}
return nil
}
func (b *Backend) Workspaces() ([]string, error) {
states.Lock()
defer states.Unlock()
var workspaces []string
for s := range states.m {
workspaces = append(workspaces, s)
}
sort.Strings(workspaces)
return workspaces, nil
}
func (b *Backend) DeleteWorkspace(name string) error {
states.Lock()
defer states.Unlock()
if name == backend.DefaultStateName || name == "" {
return fmt.Errorf("can't delete default state")
}
delete(states.m, name)
return nil
}
func (b *Backend) StateMgr(name string) (statemgr.Full, error) {
states.Lock()
defer states.Unlock()
s := states.m[name]
if s == nil {
s = &remote.State{
Client: &RemoteClient{
Name: name,
},
}
states.m[name] = s
// to most closely replicate other implementations, we are going to
// take a lock and create a new state if it doesn't exist.
lockInfo := statemgr.NewLockInfo()
lockInfo.Operation = "init"
lockID, err := s.Lock(lockInfo)
if err != nil {
return nil, fmt.Errorf("failed to lock inmem state: %s", err)
}
defer s.Unlock(lockID)
// If we have no state, we have to create an empty state
if v := s.State(); v == nil {
if err := s.WriteState(statespkg.NewState()); err != nil {
return nil, err
}
if err := s.PersistState(); err != nil {
return nil, err
}
}
}
return s, nil
}
type stateMap struct {
sync.Mutex
m map[string]*remote.State
}
// Global level locks for inmem backends.
type lockMap struct {
sync.Mutex
m map[string]*statemgr.LockInfo
}
func (l *lockMap) lock(name string, info *statemgr.LockInfo) (string, error) {
l.Lock()
defer l.Unlock()
lockInfo := l.m[name]
if lockInfo != nil {
lockErr := &statemgr.LockError{
Info: lockInfo,
}
lockErr.Err = errors.New("state locked")
// make a copy of the lock info to avoid any testing shenanigans
*lockErr.Info = *lockInfo
return "", lockErr
}
info.Created = time.Now().UTC()
l.m[name] = info
return info.ID, nil
}
func (l *lockMap) unlock(name, id string) error {
l.Lock()
defer l.Unlock()
lockInfo := l.m[name]
if lockInfo == nil {
return errors.New("state not locked")
}
lockErr := &statemgr.LockError{
Info: &statemgr.LockInfo{},
}
if id != lockInfo.ID {
lockErr.Err = errors.New("invalid lock id")
*lockErr.Info = *lockInfo
return lockErr
}
delete(l.m, name)
return nil
}