From e9a76808df4cc3eaa629969b1a2eb3d7448698dc Mon Sep 17 00:00:00 2001 From: James Bardin Date: Thu, 22 Feb 2018 20:43:21 -0500 Subject: [PATCH] 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. --- backend/backend.go | 5 ++ backend/local/backend.go | 13 ++++ backend/local/backend_apply.go | 20 ------ backend/local/backend_local.go | 12 ++++ backend/local/backend_plan.go | 22 ------ backend/local/backend_refresh.go | 22 ------ command/clistate/state.go | 114 +++++++++++++++++++++++++------ command/meta_backend.go | 32 +++------ command/meta_backend_migrate.go | 16 ++--- command/taint.go | 7 +- command/untaint.go | 8 +-- command/workspace_delete.go | 8 +-- command/workspace_new.go | 8 +-- 13 files changed, 144 insertions(+), 143 deletions(-) diff --git a/backend/backend.go b/backend/backend.go index f67d60ab6..dfeb80ef6 100644 --- a/backend/backend.go +++ b/backend/backend.go @@ -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 diff --git a/backend/local/backend.go b/backend/local/backend.go index b42aedb17..eb4eff4b0 100644 --- a/backend/local/backend.go +++ b/backend/local/backend.go @@ -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) }() diff --git a/backend/local/backend_apply.go b/backend/local/backend_apply.go index da8c684bc..102d40c39 100644 --- a/backend/local/backend_apply.go +++ b/backend/local/backend_apply.go @@ -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() diff --git a/backend/local/backend_local.go b/backend/local/backend_local.go index aa056a1a1..d26fefa57 100644 --- a/backend/local/backend_local.go +++ b/backend/local/backend_local.go @@ -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) } diff --git a/backend/local/backend_plan.go b/backend/local/backend_plan.go index ebf053192..00c0a859d 100644 --- a/backend/local/backend_plan.go +++ b/backend/local/backend_plan.go @@ -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() diff --git a/backend/local/backend_refresh.go b/backend/local/backend_refresh.go index 959f969a3..b5ec9aa6d 100644 --- a/backend/local/backend_refresh.go +++ b/backend/local/backend_refresh.go @@ -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() { diff --git a/command/clistate/state.go b/command/clistate/state.go index f02f053be..9bd9fe940 100644 --- a/command/clistate/state.go +++ b/command/clistate/state.go @@ -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 } diff --git a/command/meta_backend.go b/command/meta_backend.go index 2fa4ff542..726f3b70c 100644 --- a/command/meta_backend.go +++ b/command/meta_backend.go @@ -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 diff --git a/command/meta_backend_migrate.go b/command/meta_backend_migrate.go index 7f60a6605..be20a4476 100644 --- a/command/meta_backend_migrate.go +++ b/command/meta_backend_migrate.go @@ -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. diff --git a/command/taint.go b/command/taint.go index 626f88a46..c3d6c4cc9 100644 --- a/command/taint.go +++ b/command/taint.go @@ -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 diff --git a/command/untaint.go b/command/untaint.go index 1eca20277..9a2e43b24 100644 --- a/command/untaint.go +++ b/command/untaint.go @@ -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 diff --git a/command/workspace_delete.go b/command/workspace_delete.go index 99dac86d3..8a9f792e1 100644 --- a/command/workspace_delete.go +++ b/command/workspace_delete.go @@ -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) diff --git a/command/workspace_new.go b/command/workspace_new.go index 71c9fdc1f..430ecc58b 100644 --- a/command/workspace_new.go +++ b/command/workspace_new.go @@ -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