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create clistate.Locker interface 

Simplify the use of clistate.Lock by creating a clistate.Locker
instance, which stores the context of locking a state, to allow unlock
to be called without knowledge of how the state was locked.

This alows the backend code to bring the needed UI methods to the point
where the state is locked, and still unlock the state from an outer
scope.

Provide a NoopLocker as well, so that callers can always call Unlock
without verifying the status of the lock.

Add the StateLocker field to the backend.Operation, so that the state
lock can be carried between the different function scopes of the backend
code. This will allow the backend context to lock the state before it's
read, while allowing the different operations to unlock the state when
they complete.
This commit is contained in:
James Bardin 2018-02-22 20:43:21 -05:00
parent 7c6072c2a0
commit e9a76808df
13 changed files with 144 additions and 143 deletions
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5
backend/backend.go
View File

@ -9,6 +9,7 @@ import (
"errors"
"time"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/config/module"
"github.com/hashicorp/terraform/state"
"github.com/hashicorp/terraform/terraform"
@ -135,6 +136,10 @@ type Operation struct {
// state.Lockers for its duration, and Unlock when complete.
LockState bool
// StateLocker is used to lock the state while providing UI feedback to the
// user. This will be supplied by the Backend itself.
StateLocker clistate.Locker
// The duration to retry obtaining a State lock.
StateLockTimeout time.Duration

13
backend/local/backend.go
View File

@ -13,6 +13,7 @@ import (
"sync"
"github.com/hashicorp/terraform/backend"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/helper/schema"
"github.com/hashicorp/terraform/state"
"github.com/hashicorp/terraform/terraform"
@ -260,12 +261,24 @@ func (b *Local) Operation(ctx context.Context, op *backend.Operation) (*backend.
cancelCtx, cancel := context.WithCancel(context.Background())
runningOp.Cancel = cancel
if op.LockState {
op.StateLocker = clistate.NewLocker(stopCtx, op.StateLockTimeout, b.CLI, b.Colorize())
} else {
op.StateLocker = clistate.NewNoopLocker()
}
// Do it
go func() {
defer done()
defer stop()
defer cancel()
// the state was locked during context creation, unlock the state when
// the operation completes
defer func() {
runningOp.Err = op.StateLocker.Unlock(runningOp.Err)
}()
defer b.opLock.Unlock()
f(stopCtx, cancelCtx, op, runningOp)
}()

20
backend/local/backend_apply.go
View File

@ -11,7 +11,6 @@ import (
"github.com/hashicorp/errwrap"
"github.com/hashicorp/go-multierror"
"github.com/hashicorp/terraform/backend"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/command/format"
"github.com/hashicorp/terraform/config/module"
"github.com/hashicorp/terraform/state"
@ -55,25 +54,6 @@ func (b *Local) opApply(
return
}
if op.LockState {
lockCtx, cancel := context.WithTimeout(stopCtx, op.StateLockTimeout)
defer cancel()
lockInfo := state.NewLockInfo()
lockInfo.Operation = op.Type.String()
lockID, err := clistate.Lock(lockCtx, opState, lockInfo, b.CLI, b.Colorize())
if err != nil {
runningOp.Err = errwrap.Wrapf("Error locking state: {{err}}", err)
return
}
defer func() {
if err := clistate.Unlock(opState, lockID, b.CLI, b.Colorize()); err != nil {
runningOp.Err = multierror.Append(runningOp.Err, err)
}
}()
}
// Setup the state
runningOp.State = tfCtx.State()

12
backend/local/backend_local.go
View File

@ -1,9 +1,11 @@
package local
import (
"context"
"errors"
"log"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/command/format"
"github.com/hashicorp/terraform/tfdiags"
@ -20,6 +22,12 @@ func (b *Local) Context(op *backend.Operation) (*terraform.Context, state.State,
// to ask for input/validate.
op.Type = backend.OperationTypeInvalid
if op.LockState {
op.StateLocker = clistate.NewLocker(context.Background(), op.StateLockTimeout, b.CLI, b.Colorize())
} else {
op.StateLocker = clistate.NewNoopLocker()
}
return b.context(op)
}
@ -30,6 +38,10 @@ func (b *Local) context(op *backend.Operation) (*terraform.Context, state.State,
return nil, nil, errwrap.Wrapf("Error loading state: {{err}}", err)
}
if err := op.StateLocker.Lock(s, op.Type.String()); err != nil {
return nil, nil, errwrap.Wrapf("Error locking state: {{err}}", err)
}
if err := s.RefreshState(); err != nil {
return nil, nil, errwrap.Wrapf("Error loading state: {{err}}", err)
}

22
backend/local/backend_plan.go
View File

@ -9,12 +9,9 @@ import (
"strings"
"github.com/hashicorp/errwrap"
"github.com/hashicorp/go-multierror"
"github.com/hashicorp/terraform/backend"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/command/format"
"github.com/hashicorp/terraform/config/module"
"github.com/hashicorp/terraform/state"
"github.com/hashicorp/terraform/terraform"
)
@ -62,25 +59,6 @@ func (b *Local) opPlan(
return
}
if op.LockState {
lockCtx, cancel := context.WithTimeout(stopCtx, op.StateLockTimeout)
defer cancel()
lockInfo := state.NewLockInfo()
lockInfo.Operation = op.Type.String()
lockID, err := clistate.Lock(lockCtx, opState, lockInfo, b.CLI, b.Colorize())
if err != nil {
runningOp.Err = errwrap.Wrapf("Error locking state: {{err}}", err)
return
}
defer func() {
if err := clistate.Unlock(opState, lockID, b.CLI, b.Colorize()); err != nil {
runningOp.Err = multierror.Append(runningOp.Err, err)
}
}()
}
// Setup the state
runningOp.State = tfCtx.State()

22
backend/local/backend_refresh.go
View File

@ -8,11 +8,8 @@ import (
"strings"
"github.com/hashicorp/errwrap"
"github.com/hashicorp/go-multierror"
"github.com/hashicorp/terraform/backend"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/config/module"
"github.com/hashicorp/terraform/state"
"github.com/hashicorp/terraform/terraform"
)
@ -53,25 +50,6 @@ func (b *Local) opRefresh(
return
}
if op.LockState {
lockCtx, cancel := context.WithTimeout(stopCtx, op.StateLockTimeout)
defer cancel()
lockInfo := state.NewLockInfo()
lockInfo.Operation = op.Type.String()
lockID, err := clistate.Lock(lockCtx, opState, lockInfo, b.CLI, b.Colorize())
if err != nil {
runningOp.Err = errwrap.Wrapf("Error locking state: {{err}}", err)
return
}
defer func() {
if err := clistate.Unlock(opState, lockID, b.CLI, b.Colorize()); err != nil {
runningOp.Err = multierror.Append(runningOp.Err, err)
}
}()
}
// Set our state
runningOp.State = opState.State()
if runningOp.State.Empty() || !runningOp.State.HasResources() {

114
command/clistate/state.go
View File

@ -8,9 +8,11 @@ import (
"context"
"fmt"
"strings"
"sync"
"time"
"github.com/hashicorp/errwrap"
multierror "github.com/hashicorp/go-multierror"
"github.com/hashicorp/terraform/helper/slowmessage"
"github.com/hashicorp/terraform/state"
"github.com/mitchellh/cli"
@ -48,47 +50,119 @@ that no one else is holding a lock.
`
)
// Lock locks the given state and outputs to the user if locking
// is taking longer than the threshold. The lock is retried until the context
// is cancelled.
func Lock(ctx context.Context, s state.State, info *state.LockInfo, ui cli.Ui, color *colorstring.Colorize) (string, error) {
var lockID string
// Locker allows for more convenient locking, by creating the timeout context
// and LockInfo for the caller, while storing any related data required for
// Unlock.
type Locker interface {
// Lock the provided state, storing the reason string in the LockInfo.
Lock(s state.State, reason string) error
// Unlock the previously locked state.
// An optional error can be passed in, and will be combined with any error
// from the Unlock operation.
Unlock(error) error
}
type locker struct {
mu sync.Mutex
ctx context.Context
timeout time.Duration
state state.State
ui cli.Ui
color *colorstring.Colorize
lockID string
}
// Create a new Locker.
// The provided context will be used for lock cancellation, and combined with
// the timeout duration. Lock progress will be be reported to the user through
// the provided UI.
func NewLocker(
ctx context.Context,
timeout time.Duration,
ui cli.Ui,
color *colorstring.Colorize) Locker {
l := &locker{
ctx: ctx,
timeout: timeout,
ui: ui,
color: color,
}
return l
}
// Locker locks the given state and outputs to the user if locking is taking
// longer than the threshold. The lock is retried until the context is
// cancelled.
func (l *locker) Lock(s state.State, reason string) error {
l.mu.Lock()
defer l.mu.Unlock()
l.state = s
ctx, cancel := context.WithTimeout(l.ctx, l.timeout)
defer cancel()
lockInfo := state.NewLockInfo()
lockInfo.Operation = reason
err := slowmessage.Do(LockThreshold, func() error {
id, err := state.LockWithContext(ctx, s, info)
lockID = id
id, err := state.LockWithContext(ctx, s, lockInfo)
l.lockID = id
return err
}, func() {
if ui != nil {
ui.Output(color.Color(LockMessage))
if l.ui != nil {
l.ui.Output(l.color.Color(LockMessage))
}
})
if err != nil {
err = errwrap.Wrapf(strings.TrimSpace(LockErrorMessage), err)
return errwrap.Wrapf(strings.TrimSpace(LockErrorMessage), err)
}
return lockID, err
return nil
}
// Unlock unlocks the given state and outputs to the user if the
// unlock fails what can be done.
func Unlock(s state.State, id string, ui cli.Ui, color *colorstring.Colorize) error {
func (l *locker) Unlock(parentErr error) error {
l.mu.Lock()
defer l.mu.Unlock()
if l.lockID == "" {
return parentErr
}
err := slowmessage.Do(LockThreshold, func() error {
return s.Unlock(id)
return l.state.Unlock(l.lockID)
}, func() {
if ui != nil {
ui.Output(color.Color(UnlockMessage))
if l.ui != nil {
l.ui.Output(l.color.Color(UnlockMessage))
}
})
if err != nil {
ui.Output(color.Color(fmt.Sprintf(
l.ui.Output(l.color.Color(fmt.Sprintf(
"\n"+strings.TrimSpace(UnlockErrorMessage)+"\n", err)))
err = fmt.Errorf(
"Error releasing the state lock. Please see the longer error message above.")
if parentErr != nil {
parentErr = multierror.Append(parentErr, err)
}
}
return parentErr
}
type noopLocker struct{}
// NewNoopLocker returns a valid Locker that does nothing.
func NewNoopLocker() Locker {
return noopLocker{}
}
func (l noopLocker) Lock(state.State, string) error {
return nil
}
func (l noopLocker) Unlock(err error) error {
return err
}

32
command/meta_backend.go
View File

@ -586,15 +586,11 @@ func (m *Meta) backendFromPlan(opts *BackendOpts) (backend.Backend, error) {
lockCtx, cancel := context.WithTimeout(context.Background(), m.stateLockTimeout)
defer cancel()
// Lock the state if we can
lockInfo := state.NewLockInfo()
lockInfo.Operation = "backend from plan"
lockID, err := clistate.Lock(lockCtx, realMgr, lockInfo, m.Ui, m.Colorize())
unlock, err := clistate.Lock(lockCtx, realMgr, "backend from plan", "", m.Ui, m.Colorize())
if err != nil {
return nil, fmt.Errorf("Error locking state: %s", err)
}
defer clistate.Unlock(realMgr, lockID, m.Ui, m.Colorize())
defer unlock(nil)
}
if err := realMgr.RefreshState(); err != nil {
@ -967,15 +963,11 @@ func (m *Meta) backend_C_r_s(
lockCtx, cancel := context.WithTimeout(context.Background(), m.stateLockTimeout)
defer cancel()
// Lock the state if we can
lockInfo := state.NewLockInfo()
lockInfo.Operation = "backend from config"
lockID, err := clistate.Lock(lockCtx, sMgr, lockInfo, m.Ui, m.Colorize())
unlock, err := clistate.Lock(lockCtx, sMgr, "backend from config", "", m.Ui, m.Colorize())
if err != nil {
return nil, fmt.Errorf("Error locking state: %s", err)
}
defer clistate.Unlock(sMgr, lockID, m.Ui, m.Colorize())
defer unlock(nil)
}
// Store the metadata in our saved state location
@ -1050,15 +1042,11 @@ func (m *Meta) backend_C_r_S_changed(
lockCtx, cancel := context.WithTimeout(context.Background(), m.stateLockTimeout)
defer cancel()
// Lock the state if we can
lockInfo := state.NewLockInfo()
lockInfo.Operation = "backend from config"
lockID, err := clistate.Lock(lockCtx, sMgr, lockInfo, m.Ui, m.Colorize())
unlock, err := clistate.Lock(lockCtx, sMgr, "backend from config", "", m.Ui, m.Colorize())
if err != nil {
return nil, fmt.Errorf("Error locking state: %s", err)
}
defer clistate.Unlock(sMgr, lockID, m.Ui, m.Colorize())
defer unlock(nil)
}
// Update the backend state
@ -1193,15 +1181,11 @@ func (m *Meta) backend_C_R_S_unchanged(
lockCtx, cancel := context.WithTimeout(context.Background(), m.stateLockTimeout)
defer cancel()
// Lock the state if we can
lockInfo := state.NewLockInfo()
lockInfo.Operation = "backend from config"
lockID, err := clistate.Lock(lockCtx, sMgr, lockInfo, m.Ui, m.Colorize())
unlock, err := clistate.Lock(lockCtx, sMgr, "backend from config", "", m.Ui, m.Colorize())
if err != nil {
return nil, fmt.Errorf("Error locking state: %s", err)
}
defer clistate.Unlock(sMgr, lockID, m.Ui, m.Colorize())
defer unlock(nil)
}
// Unset the remote state

16
command/meta_backend_migrate.go
View File

@ -236,25 +236,17 @@ func (m *Meta) backendMigrateState_s_s(opts *backendMigrateOpts) error {
lockCtx, cancel := context.WithTimeout(context.Background(), m.stateLockTimeout)
defer cancel()
lockInfoOne := state.NewLockInfo()
lockInfoOne.Operation = "migration"
lockInfoOne.Info = "source state"
lockIDOne, err := clistate.Lock(lockCtx, stateOne, lockInfoOne, m.Ui, m.Colorize())
unlockOne, err := clistate.Lock(lockCtx, stateOne, "migration", "source state", m.Ui, m.Colorize())
if err != nil {
return fmt.Errorf("Error locking source state: %s", err)
}
defer clistate.Unlock(stateOne, lockIDOne, m.Ui, m.Colorize())
defer unlockOne(nil)
lockInfoTwo := state.NewLockInfo()
lockInfoTwo.Operation = "migration"
lockInfoTwo.Info = "destination state"
lockIDTwo, err := clistate.Lock(lockCtx, stateTwo, lockInfoTwo, m.Ui, m.Colorize())
unlockTwo, err := clistate.Lock(lockCtx, stateTwo, "migration", "destination state", m.Ui, m.Colorize())
if err != nil {
return fmt.Errorf("Error locking destination state: %s", err)
}
defer clistate.Unlock(stateTwo, lockIDTwo, m.Ui, m.Colorize())
defer unlockTwo(nil)
// We now own a lock, so double check that we have the version
// corresponding to the lock.

7
command/taint.go
View File

@ -7,7 +7,6 @@ import (
"strings"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/state"
"github.com/hashicorp/terraform/terraform"
)
@ -87,15 +86,13 @@ func (c *TaintCommand) Run(args []string) int {
lockCtx, cancel := context.WithTimeout(context.Background(), c.stateLockTimeout)
defer cancel()
lockInfo := state.NewLockInfo()
lockInfo.Operation = "taint"
lockID, err := clistate.Lock(lockCtx, st, lockInfo, c.Ui, c.Colorize())
unlock, err := clistate.Lock(lockCtx, st, "taint", "", c.Ui, c.Colorize())
if err != nil {
c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
return 1
}
defer clistate.Unlock(st, lockID, c.Ui, c.Colorize())
defer unlock(nil)
}
// Get the actual state structure

8
command/untaint.go
View File

@ -7,7 +7,6 @@ import (
"strings"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/state"
)
// UntaintCommand is a cli.Command implementation that manually untaints
@ -75,15 +74,12 @@ func (c *UntaintCommand) Run(args []string) int {
lockCtx, cancel := context.WithTimeout(context.Background(), c.stateLockTimeout)
defer cancel()
lockInfo := state.NewLockInfo()
lockInfo.Operation = "untaint"
lockID, err := clistate.Lock(lockCtx, st, lockInfo, c.Ui, c.Colorize())
unlock, err := clistate.Lock(lockCtx, st, "untaint", "", c.Ui, c.Colorize())
if err != nil {
c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
return 1
}
defer clistate.Unlock(st, lockID, c.Ui, c.Colorize())
defer unlock(nil)
}
// Get the actual state structure

8
command/workspace_delete.go
View File

@ -6,7 +6,6 @@ import (
"strings"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/state"
"github.com/mitchellh/cli"
"github.com/posener/complete"
)
@ -114,10 +113,7 @@ func (c *WorkspaceDeleteCommand) Run(args []string) int {
lockCtx, cancel := context.WithTimeout(context.Background(), c.stateLockTimeout)
defer cancel()
// Lock the state if we can
lockInfo := state.NewLockInfo()
lockInfo.Operation = "workspace delete"
lockID, err := clistate.Lock(lockCtx, sMgr, lockInfo, c.Ui, c.Colorize())
unlock, err := clistate.Lock(lockCtx, sMgr, "workspace delete", "", c.Ui, c.Colorize())
if err != nil {
c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
return 1
@ -132,7 +128,7 @@ func (c *WorkspaceDeleteCommand) Run(args []string) int {
// state deletion, i.e. in a CI environment. Adding Delete() as a
// required method of States would allow the removal of the resource to
// be delegated from the Backend to the State itself.
clistate.Unlock(sMgr, lockID, c.Ui, c.Colorize())
unlock(nil)
}
err = b.DeleteState(delEnv)

8
command/workspace_new.go
View File

@ -7,7 +7,6 @@ import (
"strings"
"github.com/hashicorp/terraform/command/clistate"
"github.com/hashicorp/terraform/state"
"github.com/hashicorp/terraform/terraform"
"github.com/mitchellh/cli"
"github.com/posener/complete"
@ -118,15 +117,12 @@ func (c *WorkspaceNewCommand) Run(args []string) int {
lockCtx, cancel := context.WithTimeout(context.Background(), c.stateLockTimeout)
defer cancel()
// Lock the state if we can
lockInfo := state.NewLockInfo()
lockInfo.Operation = "workspace new"
lockID, err := clistate.Lock(lockCtx, sMgr, lockInfo, c.Ui, c.Colorize())
unlock, err := clistate.Lock(lockCtx, sMgr, "workspace_new", "", c.Ui, c.Colorize())
if err != nil {
c.Ui.Error(fmt.Sprintf("Error locking state: %s", err))
return 1
}
defer clistate.Unlock(sMgr, lockID, c.Ui, c.Colorize())
defer unlock(nil)
}
// read the existing state file